Problems Posed by the use of Schizosaccharomyces Pombe in the Making of Rums

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Ganou-Parfait B., Parfait A., 1980. Problèmes posés par l’utilisation de Schizosaccharomyces pombe dans la fabrication des rhums. Industries alimentaires et Agricoles 97, 575-580.

Problems posed by the use of Schizosaccharomyces pombe in the making of rums

by B. GANOU-PARFAIT and A. PARFAIT
Station de Technologie des Produits Végétaux
Centre de Recherches des Antilles et de la Guyane, INRA
97.17O PETIT-BOURG -Guadeloupe 

SUMMARY

Schizosaccharomyces pombe can be used like Saccharomyces cerevisiae in rum technology. Strains of S. pombe have been selected for microbiological and biochemical studies. A medium with cane juice is proposed. The rates of the fermentation can be increased with yeast concentration. According to the formation of the major volatile components S. pombe seems better than Saccharomyces; nevertheless other studies are necessary to confirm potentialities.

[this was supplied in English the French which I translate below comes out noticeably different.]

Summary
In the production of rums, strains of Schizosaccharomyces pombe and those of Saccharomyces cerevisiae are used. A selection was conducted to have a collection of Schizosaccharomyces pombe on which microbiological, biochemical and technological studies were conducted. A culture medium based on cane juice is proposed. Fermentation rates are generally low, but we want to accelerate the fermentations using significant seeding rates. The level of formation of the major components among the volatiles should give preference to Schizosaccharomyces pombe. It turns out that further work is needed to allow the reintroduction of Schizosaccharomyces pombe under the best conditions in fermentation media.

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In general, the use of the selected yeasts have several advantages in fermentations leading to alcoholic beverages. The choice of corresponding yeast species and strains obeys a certain number of criteria which are fixed, but it can also be the consequence of a given industrial situation. These particular considerations are for molasses, syrups and cane juices that are raw materials in fermentations leading to rums.

Kervégant (1946) collected a series of observations on schizosaccharomyces pombe in rum. This yeast was present in fermentations, especially molasses and syrup. Several species and several strains were known. In the production of rums, budding yeasts of the Saccharomyces cerevisiae type have been preferred to Schizosaccharomyces pombe because the former are in general faster.

The use of gas chromatography, alone or in combination with other techniques, makes it possible more and more to make a complete analysis of rums under conditions that are generally quite easy. It is therefore possible to propose quality criteria for rums: absence or presence of certain compounds at given concentrations. To meet these requirements it is sometimes necessary to resort to technological innovation.

Following our observations in the French West Indies, Parfait et al. 1975 and in view of current techniques used elsewhere in the world – Kampen (1975) – it is likely that the rum industry will experience such a situation. It is therefore reasonable to envisage the reintroduction of Schizosaccharomyces pombe in fermentative media.

SELECTION OF STRAINS OF SCHIZOSACCHAROMYCES POMBE

These yeasts are common in tropical environments. Several authors have reported them in fermentations of derivatives of sugar cane. Like all Schizosaccharomyces, the essential physiological characteristic is division by fission. The spherical to cylindrical cells are often larger than those of other yeasts and in particular those of Saccharomyces cerevisiae. We first made microscopic observations. The identification of colonies obtained after plating a colony on Petri dishes is done by the method of Lodder and Van Rij. The Schizosaccharomyces pombe cells are practically absent in fermentative environments in the French West Indies, except in the case where heave-flavored rums are manufactured. These same cells are found in certain soils where sugar cane is cultivated, but there they are in very small numbers. They are much larger in the fermented musts of small distilleries in Haiti. For decades, they have not changed their manufacturing conditions, and they are often isolated in the middle of the countryside. We can therefore estimate that the modifications of the flora have been practically nil. In all cases, to facilitate the selection of strains of Shizosaccharomyces, different properties are used Ganou-Parfait (1979).

Some are mentioned below:

Table 1

Use of citric acid by S. pombe. (+) low growth, (-) no growth The concentration of citric acid is 0.5%

Table 2

The influence of butyric acid on a mixture of yeasts. The seeding rate, 1 × 10 6 / ml for each yeast, Count of revivifiable cells after 76 hours of culture at 30° C. in a medium with malt extract containing 150% of sucrose.

Sensitivity to Acids.

In rums, in general, acetic acid is the most important constituent of the acid fraction, of which it accounts for nearly 80% of the total. For a type of rum represented by the large aroma rums, the butyric acid fraction is also significant. We compared the behavior of Schizosaccharomyces pombe and Saccharomyces cerevisiae strains in the presence of varying amounts of different acids. The comparison was made either aerobically or anaerobically, and the determination of the number of total germs by the Malassez cell made it possible to measure the sensitivity of yeasts to acids.

In the case of citric acid, 10 ml of medium are placed in test tubes. In each case, citric acid is added at a concentration of 0.5%. The results are obtained on strains of Schizosaccharomyces pombe, they are shown in Table 1, and are not better if the citric acid is replaced by malic acid. Note that some authors have found that in the case of the latter acid, there is a sharp reduction in the growth of Saccharomyces cerevisiae for concentrations ranging from 0.2 to 0.4% malic acid.

The influence of increasing amounts of acetic acid on yeast growth is well known. There is a slowdown in the fermentation rate and a decrease in the amount of sugar used. The results are identical with butyric acid.

To compare the influence of the latter on a mixture of Saccharomyces cerevisiae and Schizosaccharomyces pombe, we made a count of total germs after sixteen hours. The medium used is the following: 10 ml of malt extract supplemented with sucrose at a rate of 150 g/l. The seeding rate is 1 X 10 6/ml for each yeast. The butyric acid slows down according to the concentration used, the growth of Saccharomyces cerevisiae and has a variable effect on that of Schizosaccharomyces pombe. In case we want to make a selective medium to isolate Schizosaccharomyces pombe in view of previous results the addition of 0.25% butyric acid could be a formula. However, experience shows that the results obtained on a liquid medium are not transposable in a solid medium. In all our experiments, the growth of Saccharomyces cerevisiae has always superseded that of Schizosaccharomyces pombe.

Search for a favorable environment for Schizosaccharomyces pombe

During microscopic observations, it was found that in natural samples, Schizosaccharomyces pombe cells had a granular appearance which disappeared after multiplication of the cells in a favorable medium. We have sorted in a large number of culture media used for yeasts. During this operation the following conclusions were reached:

Peptones represent a better source of nitrogen than ammonium salts. In fact, when comparing the ammonium salts with each other, it is found that the acidity induced by the anion is an essential factor. The optimum pH is of the order of 5, but the pH range is from 4 to 6. Sucrose is better assimilated than glucose.

We compared several synthetic media: Wickerham malt, Czapek, Dox Agar, Davis Yeast Salt Agar, malt extract. This last medium supplemented with sucrose gives the best results. We made different media formulas from cane juice and molasses. It is with cane juice that we have the best results. We therefore propose the following medium:

— Peptone = 1 g
— Ammonium Sulfate = 2 g
— Cane Juice = 1.000 ml.

The pH is adjusted to 5, sterilized at 120 ° C for 15 minutes. In order to reduce the importance of flocculation during sterilization, peeled sugar canes are used.

Selection Results

Of all the samples we have studied, we have extracted a strain of yeast to make rums of great aroma, and sixty strains from different media collected in Haiti. Beside these last strains, we also found about ten strains of Schizosaccharomyces malidevorans. This species is easily distinguished because it is the only Schizosaccharomyces that does not use maltose. It should be noted that Schizosaccharomyces sporulate with difficulty, whatever the medium used.

GROWTH OF STRAINS OF SCHIZOSACCHAROMYCES POMBE

Generally, Schizosaccharomyces pombe is considered to have a low growth rate. In order to get closer to the industrial criteria, we used the procedure below to compare the strains.

The cells proliferate for 72 hours at 30° C on agitated Wickerham malt medium. They are recovered by centrifugation 3,000 tr/15 minutes, and then washed. After counting, a molasses-based medium is inoculated at 1 X 10 6 yeast / ml. The fermentation is carried out in 125 ml flasks closed with a rubber stopper crossed by a tapered glass tube at one end, and plugged at the other end with carded cotton.

The environment is as follows:

— Molasses 300 g
— Ammonium Sulfate = 1 g
— Water q.s.p. = 1.000 m)
— pH = 5.2, sterilization 15 minutes at 110°C.

The fermentation curves are plotted in Figure 1. From this examination it appears that the lag phase is longer for Schizosaccharomyces pombe and that overall the fermentation rate is lower than that of Saccharomyces cerevisiae.

But fermentation rates can be varied by increasing seeding rates. The tests are conducted under the same conditions as above, with different seeding rates determined by the dry matter. Fermentation rates are conventionally represented by the mass losses of each vial after 24 hours.

Table III Fermentation speed for increasing rates of seeding with Schizosaccharomyces pombe

We find in Table III results similar to those we found with S. cerevisiae. It can therefore be estimated that for large seeding rates (2 to 5 g/L) the behavior of these two yeast species is close.

Use in Industrial Fermentation

For twenty years, there has been an interest in the use of Schizosaccharomyces pombe to deacidify wines, Bidan (1974). During this operation, the malic acid is converted into ethanol.

In his important work on rums, Arroyo found that both species Schizosaccharomyces pombe and Saccharomyces cerevisiae could both provide good products. In making rums, he advocated the second because it fermented faster. Recently, Rose (1976) has selected S. pombe strains from yeasts that can produce from molasses musts an alcohol content of 11° to 12° GL. Such a concentration of ethanol makes it possible, compared with conventional methods, to reduce the quantities of energy required during distillation relative to wines of 4-5 ° GL.

Today, S. pombe is a fermentative agent of cane molasses next to several Clostridia including Clostridium acetobutylicum in the manufacture of grand arôme. This type of rum in the French West Indies is characterized by a high level of non-alcohol (800-1,800 g/hl pure alcohol). In detail, there is a significant fraction of ethyl acetate and acetic acid, about 300 grams for each term and a small amount of higher alcohols — less than 100 g — with a abundance of n-propanol. The musts are composed with vinasses [stillage or dunder] that have surely undergone the phenomena of pre-fermentation. They are rich in volatile acids and in fixed acids. Fermentations are slow and must involve different metabolic pathways that have not yet been fully elucidated.

Products of Fermentation

Among the compounds found in rums, some are already present in molasses as a result of various more or less advanced prefermentations. But yeast is mainly responsible for their formation during the alcoholic fermentation. In various previous works, Parfait (1977-79), we have studied certain products of the molasses fermentation by S. pombe, which can be referred to for the various procedures.

a. Ethyl esters of higher fatty acids

Pombe produces more of these compounds than most baker’s yeasts of the species Saccharomyces cerevisiae, but some good yeasts in our collection belonging to this species have equivalent productions to S. pombe. This production is related (FIG. 2) with the cell growth yield that can be appreciated by the ratio of final yeast to initial yeast. For seeding rates between 0.1 and 5 g /L yeast dry matter, there is a correlation between the amount of ester produced and the cell yield. This proportionality is also checked for each ester in the series.

b. Ethyl Acetate

In quantity, ethyl acetate is the main ester of rums made with Saccharomyces cerevisiae. Under the same conditions of fermentation and distillation S. pombe brings a double production, 100 g/hl of pure alcohol instead of 50 g/hl pure alcohol. In industrial rums of high aroma type, the production is very strong, more than 300 g/ hl pure alcohol without the production of ethyl esters of higher fatty acids is affected. Esterification is primarily a biochemical phenomenon, distillation in the presence of yeasts can increase the levels of ethyl esters of rums, but their formation involves acetyl CO A. If we are inoculating a must of molasses with a mixed culture of Schizosaccharomyces pombe and Clostridium acetobutylicum, the presence of the bacterium has the effect of increasing the amount of ethyl acetate formed. One may wonder if under certain culture conditions, especially in musts leading to rums of high aroma type where the medium is already rich in acetic acid, there is no different functioning of esterase.

c. Higher Fatty Acids

Caprylic and capric acids are the major constituents of this fraction of rums made with Saccharomyces cerevisiae or Schizosaccharomyces pombe. Temperature and pH affect the total production of higher fatty acids, just as they affect the general activity of yeast. Depending on the sugar concentration, fatty acid concentrations increase in rums made from Schizosaccharomyces pombe, except for caprylic (Table IV).

Table IV: Influence of molasses concentration on the formation of higher fatty acids. The results for the fatty acids are expressed in mg/l of pure alcohol. The initial seeding rate is 3 g/l

d. Acetic Acid

In pure culture, the productions of acetic acid are comparable for Schizosaccharomyces pombe and Saccharomyces cerevisiae. The high levels of acetic acid found in the aroma of rums originate from the vinasses which enter into the composition of the must and the further extraction during the distillation.

e. The Higher Alcohols

We have already reviewed the mechanisms of formation of higher alcohols, Parfait (1975). The Schizosaccharomyces pombe strains generally provide fewer higher alcohols than those of Saccharomyces cerevisiae, and this with a predominance for n-propanol.

DISCUSSION

A number of questions arise when using Schizosaccharomyces pombe in the production of rums.

The growth of yeast is lagging at low seeding rates. It is possible to accelerate the fermentations by increasing this rate. This technological device must not obscure the different physiological behaviors of Saccharomyces cerevisiae and Schizosaccharomyces pombe. In the study of a suitable medium for the culture of this last yeast, we found that sucrose was better than glucose. This result was explained by Hayashibe (1973). The growth curves are not the same for glucose and mannose on the one hand, and sucrose on the other hand; but fermentation rates are the same when using cell extracts. It can therefore be linked to sugar transport phenomena. Billon-Grand (1977) demonstrated the existence of intracellular enzymes 1α and β glucosidases and invertase or β fructofuranosidase, capable of degrading these sugars. As often in this case, the transport of sugars is facilitated by the addition of NH4 + ions in the medium. It should be noted that Schizosaccharomyces pombe does not use glycerol and ethanol. This difference with Saccharomyces may partly explain the high levels of glycerol. Many studies have been done on the influence of oleic acid and sterols in the anaerobic metabolism of several yeasts. Very little data has been established on the fatty acid and lipid composition of yeasts of the genus Schizosaccharomyces. Their obtaining will thus explain the importance of the lag phase for these microorganisms. Bush (1977) has confirmed the absence of mannan which plays a role in the budding process of several yeasts, but the presence of galactomannan raises the question of the nature of the compounds that play a role in the fission process. Similarly, there is a difference in the plasticity of the cell wall and its protective role vis-à-vis the cellular content. Ultimately, the composition of the cell membrane and its impact on Schizosaccharomyces pombe metabolism are important enough to explain the differences in physiological behavior with Saccharomyces.

Of the volatile compounds produced during fermentation by Schizosaccharomyces pombe, special mention must be made of ethyl acetate and higher alcohols. Part of the ethyl acetate arises as a result of the oxidative decarboxylation of pyruvic acid and an alcoholysis reaction:
(1) CH3CO COOH — NAD — CoA v SH –———>

CH3CO v SCoA + NADH2 + CO2

[not sure about this notation and what the italicized “v” stands for]

(2) CH3CO SCOA + CH3CH2OH ——->
CH3 COOC2H5 + HS v CoA

But the high concentration of acetic acid that exists in some musts may explain the formation of ethyl acetate by shifting the equilibrium during the reaction.

(3) CH3 COOH + CH3CH2OH ⇔ CH3 COOCH2
CH2 + H2O

We will undertake enzymatic and kinetic studies of these three reactions to justify the different levels of ethyl acetate found in rums.

The amounts of each higher alcohol manufactured by Schizosaccharomyces pombe are quite remarkable: low levels of methyl-3-butanol. 1, methyl 2 – butanol 1, and isobutanol, against a higher propanol content. The latter is manufactured in the following way:

Thréonine –» amino acid – 2 butenoïque –» acide
thréonine déhydratase
deaminase σ cétobutyrique –> CO2 — τn propanaldéhyde –>
n propano
décarboxylation déhydrogénase

[I’m insecure about translating this section. Any help? and background on it?]

This route for propanol is specific, even though it contains σ ketobutyric acid, which is a key intermediate in the biosynthetic formation of other higher alcohols. We have done a nearly complete study of the formation of higher alcohols in rums. It appears necessary, in the case of Schizosaccharomyces pombe, to determine the variations of the amino acid pool, taking into account the ambient factors and in particular the nitrogen diet during the fermentation.

Without waiting for its results, our first observations – Pafait, (1977) – showed that by means of the acceleration of fermentations can ferment with Schizosaccharomyces pombe molasses musts containing 150 to 180 g/l of sugar under conditions as well as can Saccharomyces cerevisiae. For this last yeast, it appears that the choice of the strain is determining in the level of formation of the volatile products and in the fermentative efficiency. This is also the case for Schizosaccharomyces pombe and some strains show, in particular, a very low fermentative efficiency. The properties of these yeasts begin to be explained through different biochemical studies.

Here we have specified a number of pathways (cell membrane formation and metabolite transport, kinetics of ethyl acetate formation, composition and amino acid pool variation) that are promising. Besides this, an organoleptic study of rums is needed. We chose the technique of Micko – Parfait, (1979) – for the tasting of rums and cane spirits. Equivalent fractions may have a different flavor depending on the yeast and the strain that served as the fermentation agent. The perception thresholds of each constituent are not the same depending on whether they are used alone or in association with other bodies. Nowadays, the distillates obtained from Schizosaccharomyces pombe and Saccharomyces cerevisiae have different contents, at least for the main constituents: higher alcohols, aldehyde and ethyl acetate. Finally, it is as a result of various technological operations, fermentation, distillation, assembly, maturation that the rums obtained from Saccharomyces cerevisiae present a composition and a favor given. The reintroduction of Schizosaccharomyces pombe in fermentation media will allow these different operations to be carried out under other conditions to obtain products equivalent to those which now exist.

CONCLUSION

Different studies have shown that the current compositional criteria for rums can be more easily achieved with Schizosaccharomyces pombe as a fermentative agent, rather than Saccharomyces cerevisiae. The selection of strains of this first yeast, even in favorable ecological environments, has only been made possible by a study of some of its microbiological and physiological properties. The use of Schizosaccharomyces pombe in musts made from molasses and sugar cane juice poses a series of biochemical, technological and organoleptic problems whose solution lies in a better knowledge of the metabolic pathways. This preliminary work made it possible to determine the axes that will be the subject of future research.

BBLOGRAPHE

G. BILLON-GRAND (1977). – Recherche d’enzymes intracellulaires dans le genre Schizosaccharomyces, lmplications systématiques. Mycopathology, 61 (2), 111-115 

P. Bidan (1974). — Les Schizosaccharomyces en CEnologie.
Bull. OIV, 47 (523), 682-706.

D.A. BUSH, M. HORISBERGER, I. HORMAN, P. WURSCH, 1977. – The wall structure of Schizosaccharomyces pombe. Nestlé research News, 73-77.

M. HAYASHIBE, N. SANDO, Y. OHBA, K. NAKAMURA, K. DKA., K. KONNO, M. GOYO (1973). — Utilisation of hexoses in fission yeast. Proceedings of the 3rd international specialized symposium on yeast OTANIEN. Helsinki Part, II, 91-102.

B. GANOU, PARFAIT, 1979. — Les microorganismes des fermentations de mélasse et de jus de cannne. 1979 (en préparation).

D. KAMPEN (1975). – Technology of the rum industry. Sugar y azucar, 70 (8), 36-43.

KERVEGANT (1946). – Rhums et eaux-de-vie de canne. Les Editions du Golfe, Vannes.

A. PARFAIT (1972). — Les esters éthyliques des acides gras supérieurs de rhums. Ann. Technol. Agric.., 21 (2), 199-210.

A. PARFAIT (1975). – Formation des alcools supérieurs dans les rhums. Ann. Technol. Agric., 24 (3-4), 421-436.

A. PARFAIT et G. SABIN (1975). — Les fermentations traditionnelles de mélasses et de jus de canne aux Antilles françaises. Industries alimentaires et agricoles, 2 (1) 27-30.

A. PARFAIT (1977). — La fabrication des rhums. Rapport d’un contrat DGRST, No 74-7-09-06.

A. PARFAIT (1979). — Suite de l’étude sur la fabrication des rhums. Rapport d’un contrat DGRST, No 77-7-03-55.

D. ROSE (1976). – Yeasts for Molasses alcohol. Process Biochemistry, 12 (2), 10-16.

Fermentation Properties of Rhumerie Yeasts

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Fahrasmane L., Parfait A., Galzy P., 1986. Propriétés fermentaires des levures de fermentation. Industries alimentaires et Agricoles 103, 125-127.

Fermentation Properties of Rhumerie Yeasts
by L. Fahrasmane*, A. Parfait*, P. Galzy**

* Station de Technologie INRA-Antilles – Domaine Duclos 97170 Petit-Bourg
** Laboratoire de la chaire génétique ENSAM, Place Viala, 34060 Montpellier

Introduction
Fermentations of molasses and sugar cane juice take place in the West Indies, in a non-sterile environment (Parfait and Sabin, 1975). Formerly, the dominant yeast species was Schizosaccharomyces pombe Lindner. This yeast is osmophilic and often gives rums of quality in association with an abundant bacterial flora. She was most often supplanted by Saccharomyces cerevisiae Hansen. The latter species, baker’s yeast, was commercially available in bulk and at low prices. It was therefore tempting for manufacturers to regulate and accelerate fermentations by massive sowing of baker’s yeast.

The purpose of this note is to compare the fermentative properties of these two species which are still the pivot of rum fermentations. We will not present here the result of a particular experiment, but rather a synthesis of several independent studies carried out on laboratory strains in sterile medium (Parfait et al., Perfect et Jouret, 1975, 1979, Fahrasmane, 1983, Fahrasmane et al., 1985); these results are discussed in the light of numerous industry observations and long experience in making rums acquired by some of us.

Material and Methods

1. Biological Materials
Most of the works summarized or cited here have been done with a large number of Strains. However, to simplify the presentation we have limited ourselves voluntarily to give results of a strain of each species considered representative. These two strains are:

– Saccharomyces cerevisiae listed 493,
– Schizosaccharomyces pombe listed G.

2. Culture Media
We used a cane juice (vesou) from natural and health canes, diluted to 100 g/l of sugar; a molasses-based medium also reduced to 100 g/l of sugar and a synthetic medium according to Oura (1974) supplemented with the main organic acids of cane juice according to Fahrasmane (1983).

3. Analysis Techniques
We used the Classic methods of rums study, including:

-the official method of assaying the higher alcohols in the eaux de vie (Fraud Control, Anonymous, 1973).
-Jouret’s method for the determination of short chain fatty acids described by Fahrasmane et al. (1983).
-The method described by Parfait et al. (1972) for the determination of ethyl esters of higher fatty acids.

Experimental Results

I. Biomass and ethanol production

Schizosaccharomyces pombe generally gives slow growth and a relatively small amount of biomass, much lower than that obtained with Saccharomyce cerevisiae (table 1). The difference between the two species fades in the case of a mixed culture. It Seems that Schizosaccharomyces pombe has special nutritional requirements that it does not find on synthetic medium or on cane juice (Vesou); on the contrary, it finds them in the much richer environment constituted by molasses. This result suggests difficulties in all industrial uses of Schizosaccharomyces pombe. The addition in a synthetic medium of the organic acids of the cane juice, in particular of cis-Aconitic acid, causes an abundant cell multiplication. This result suggests that these acids activate cell multiplication by probably intervening in the Krebs Cycle. He also explains that the yeast populations observed in crops on cane products are still exceptionally abundant. Correlatively, the yield of ethanol is not very good in rum fermentation.

The yield of ethanol expressed as a percentage of the Pasteur yield is always higher, in pure culture, for Schizosaccharomyces pombe than for Saccharomyces cerevisiae. This observation very largely explains the current craze of certain distillers who recommend the use of Schizosaccharomyces pombe.

The fermentation times are always very long for Schizosaccharomyces pombe. As a result, the fermentation medium is always more sensitive to bacterial contamination. The duration of the fermentation become extremely long on synthetic medium; the use of Schizosaccharomyces pombe for fermenting new substrates in relatively poor environments certainly has an indisputable randomness.

It should be noted that Schizosaccharomyces pombe produces significant amounts of glycerol (8 to 10 g/l per 100 grams of fermented sugar); under the same conditions, Saccharomyces cerevisiae produces only 2-3 g/l (Parfait and Jouret, 1980). Given the large bacterial flora able to attack glycerol in rum fermentation, this character is certainly a serious problem for the use of Schizosaccharomyces роmbe.

II. Formation of Higher Alcohols

Using the same culture media we studied the higher alcohols produced by both strains (Table II).

Schizosaccharomyces pombe produces far fewer higher alcohols than Saccharomyces cerevisiae. However, it appears again here that Schizosaccharomyces pombe is more sensitive to environmental conditions than Saccharomyces cerevisiae. While the latter species gives total higher alcohol concentrations substantially independent of the culture conditions, Schizosaccaromyces pombe produces twice as much higher alcohols in molasses culture than in the other Crop Conditions tested.

III. Formation of Volatile Fatty Acids

Again (Table 3), Schizosaccharomyces pombe produces much less short-chain fatty acids, important constituents of the aroma of rums, than Saccharomyces cerevisiae. It is worth mentioning that both species produce propionic acid on cane juice medium. Only Schizosaccharomyces pombe produces acrylic acid; it is probable that propionic acid is the precursor of acrylic acid. It is also likely that sugarcane media contain a propionic acid precursor for use by both yeasts.

In cultures on product derived from sugar cane (molasses) it also appears in the medium of long chain fatty acids C8 to C16 as well as the corresponding ethyl esters. Fermentation of 100 g of sugar yields about 80 to 100 mg/l of these esters regardless of the yeast species used (Parfait et al., 1972).

Conclusion
Schizosaccharomyces pombe presents in the laboratory the considerable advantage of giving a high yield of ethanol; it also has the advantage of giving relatively few higher alcohols and fatty acids. In fact, it seems obvious that these two advantages are related. Low cell growth, partly indirectly responsible for good ethanol yield, is not only beneficial; a slow and slow growth of the yeasts largely leaves room for bacterial developments. The abundant production of glycerol is also a favorable factor for the development of many germs, some aroma beneficial, other sources of manufacturing flaws. These general properties should make Schizosaccharomyces pombe a good strain of rum fermentation: it is able to give very aromatic rums with a good bacterial flora; it could give very light rums, particularly sought after, as long as one manages to control the flora; unfortunately manufacturing flaws can occur.

In recent years, it has been sought by industrialists for new substrates for the production of ethanol. Schizosaccharomyces pombe could a priori be suitable for the production of alcohol for chemical use or rectified alcohol as only a few secondary products are formed. The results we have presented show that this species is very demanding from the point of view of growth needs. This can result in a significant over-cost related to the need to complement the new fermentation media. The relative fragility of the fermentative medium with respect to bacterial contamination is also a disadvantage that should not be underestimated.

Saccharomyces cerevisiae gives higher amounts of higher alcohols and fatty acids; the yield of ethanol is a little lower than that observed in Schizosaccharomyces pombe. But the growth is fast and abundant, the occupation of the ground is good, the danger of serious bacterial accidents is reduced. This species ultimately makes it possible to obtain relatively light rums. For fermentations of new products, this species has definite advantages, provided that the substrate to be fermented is accessible (hexose, sucrose or maltose).

The characteristics of these two species explain fairly well the evolution of the rum fermentation technique. In the past, rum was prepared almost exclusively from molasses.

Vinasses [dunder or stillage] were recycled as a means of diluting molasses. Thus the fermentation medium was rich in mineral salts, nitrogenous matter. Osmotic pressure was important. This medium was favorable to Schizosaccharomyces pombe which was naturally selected. This system also favored the preferential proliferation of heat-resistant, sporulated, anaerobic bacteria. This resulted in a very particular type of rum. The sugar crisis helped, it was made more and more of direct fermentation of Vesou [fresh cane juice]. The osmotic pressure became much weaker here. The medium was poorer in biotic elements and lacked nitrogen feed for the yeast. Under these conditions, it was inevitable that Saccharomyces cerevisiae would replace Schizosaccharomyces pombe. In the same way, the dominant bacteria flora became naturally present on sugar cane: aerobic Coryneform bacteria, aerobic Bacillus, and lactic flora. The Yeast defend better against this type of flora, it resulted in a lighter rum and better suited to current consumption. It seems clear to us that the lessons learned from a reflection on the rum industry are not without interest for other ethanol manufacturing industries be it alcohol, alcohol for industrial use or alcohol fuel.

It would be useful to better understand the nutritional requirements and the general metabolism of the fermentation strains of these two species. This work becomes more and more necessary as the variety of used substrates expands. Let’s mention in the case of rum the range of raw materials: vesou, juice defecated, syrup and molasses at various stages including molasses final.

[The vesou here as opposed to defecated juice may refer to what Cape Verde uses which isn’t centrifuged and strained.]

Bibliography

FAHRASMANE L. – 1983 – Contribution à l’étude de la formation des acides gras Courts et des alcools supérieurs par des levures de rhumerie. Thèse de 3° cycle. USTL Montpellier.

FAHRASMANEL, PARFAITA., JOURETC., GALZY P. – Production of higher alcohols and short chain fatty acids by different yeats used in rum fermentation. Accepte pour publication le 22 avril 1985 par Journal of Food Science.

OURA E. – 1974 – Some aspects of aeration intensity on the biochemical composition of baker’s yeast. 1. – Factors affecting the type of metabolism. Biotechnol-Bioeng. 16, 9, 1197.

PARFAITA., NAMORY M., DUBOIS P. — 1972 — Les esters éthyliques des acides gras supérieurs des rhums. Ann. Technol. Agric., 21, 2, 199-210.

PARFAITA., SABIN G. — 1975 – Les fermentations traditionnelles de mélasse et de jus de canne aux Antilles Françaises. Ind. Agric. Alim., 92, 1, 27-34.

PARFAITA, JOURET C. — 1979 – Rapport fin de Contrat DGRST. Décision d’aide n° 74 70906 et 74 7O 907.

PARFAITA., JOURETC. – 1980 – Le glycérol dans la fermentation alcoolique des mélasses et des jus de canne à sucre. Industries alimentaires et agricoles, 7-8, 721-724.

Répression des fraudes – 1973 – Méthodes officielles d’analyse des alcools et eauxde-vie. J.O. de la République Française du 2.10, no 73-231.

Presence Of Acrolein Derivatives In A Rum Of Abnormal Taste

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Dubois P., Parfait A., Dekimpe J., 1973. Présence de dérivés de l’acroléine dans un rhum à goût anormal. Annales de Technologie Agricoles 22, 2, 131–135.

This is part of a series where French language papers related to the production of fine rums are translated to help emerging industry and celebrate the work of great scientists. I translated everything with google then did a little minor poetic rendering. What is interesting is that the end has abstracts in English, Spanish, and Italian, and that much of the bibliography comes from the whiskey industry illustrating that the faults they are studying overlap.

PRESENCE OF ACROLEIN DERIVATIVES IN A RUM OF ABNORMAL TASTE
by
P. DUBOIS, A. PARFAIT * et Jocelyne DEKIMPE
Station de Technologie des Produits végétaux,
Centre de Recherches, I. N. R. A.,
B.V. 1540, 21034 Dijon Cedex
* Station de Technologie des Produits végétaux, I. N. R. A.,
97.170 Petit-Bourg
(Сuаdelоuре)

Abstract
A rum with an abnormal taste was analyzed by gas chromatography and mass spectrometry. Two compounds were identified as 3-ethoxypropanal and 1,1,3-triethoxypropane, in addition to ethanol of acrolein. These compounds have already been found in “peppered” whiskeys whose abnormal taste also comes from the formation of acrolein during fermentation.

Key words: rum, acrolein, aroma, gas chromatography, mass spectrometry.

Introduction
The presence of an abnormal taste was reported in some freshly distilled rums. Their pungent smell disappears through aeration, but at the end of tasting we can perceive a taste that tasters have described as “phenolic” or “pharmaceutical”. This is what distillers call the taste of the still, which disappears after a longer or shorter time.

Material and Methods

A 500 ml sample of aerated peppered rum, freshly distilled and shipped to Martinique in a glass bottle, was redistilled until almost complete removal of the ethanol in a glass apparatus with a Vigreux column of 5o cm. The distillate, rediluted with an equal volume of water, had a normal taste, and the analysis focused on the residue.

By extraction with diethyl ether and total evaporation of this solvent, we obtained a few tenths of a ml of a concentrate having a strong smell of rum, but of unpleasant taste, even after dilution in a alcoholic-water solution at 50 ° GL. This concentrate was analyzed in gas chromatography-mass spectrometer coupling under the conditions indicated in Table I.

Results
The beginning of the chromatogram obtained is shown in FIG. I. Two unusual peaks surround the peak of 2-methylbutanol and 3-methylbutanol which are not separated on the liquid phase used. The mass spectrum of compound A, which is indicated in FIG. 2, is in good agreement with that published by Stenhagen et al. (I969) for 3-ethoxypropanal. The peaks M + —1 (m/e = 101) and M+—44 (m/e = 58) are characteristic of aliphatic aldehydes, although here the hydrogen rearrangement leads to the formation of the peak M+— 44 is done by a way a little different from that which is conventional, because of the presence of oxygen in the gamma position. The peak M+—28 (m/e = 74) corresponds to the loss of one molecule of ethylene and is nothing other than the parent peak of 3-hydroxypropanal (Figure 3). This compound breaks up in turn to give the ions at m/e = 73 (loss of a hydrogen), at m/e = 45 (+CH2-CH2-OH) and at m/e = 31 (CH2 = +OH). In the case of 2-ethoxypropanal, the peak at m/e = 45 should logically be more intense than the peak at m/e = 31.

Compound B (Figure 1) is the acetal of this aldehyde: triethoxy-1, 1,3 propane. The retention volumes and the mass spectra of the two compounds were verified by analysis of the corresponding synthetic products.

Discussion and Conclusion
Maarse and ten Noever de brauw (1966) reported the presence of 2-ethoxypropanal in rums, but it is more likely that it is 3-ethoxy propanal as indicated by Kahn et al. (1968, 1969) in the case of so-called “peppered” whiskeys. This ethoxy-propanal is formed by the addition of ethanol to the double bond of acrolein (Kahn, Laroe and Conner, 1968), during which the ethoxy radical is attached to the carbon atom having the lowest electron density, that is to say in position 3 in the case of acrolein. There is every reason to believe that this reaction occurs during distillation, when acrolein is in the presence of a high concentration of ethanol and at high temperature.

The production of acrolein has been studied during the alcoholic fermentation of wines since Pasteur showed, in 1886, that it was formed at the expense of glycerol, because of the metabolic activity of certain facultative anaerobic bacteria. More recently, this problem has been studied in the case of “peppered” whiskeys by Mills, Baugh and Conner (1954) and by Serjak et al. (1954).

However, neither 3-ethoxypropanal nor triethoxy-1,3 propane appears to have the abnormal taste of the rum studied, even after dilution of these products in ethanol at 5o°GL. Now, it suffices to distill a mixture of water, ethanol and acrolein, to aerate the distillate and to dilute it with an equal volume of water to obtain the desired abnormal taste.

Thus, the abnormal taste observed, on the one hand, and the presence of 3-ethoxypropanal and 1,1,3-triethoxy propane, on the other hand, are both related to the presence of acrolein in the base wine. As for acrolein remaining free, it must be found in the distillation heads or have been removed from the distillate during aeration.

Other derivatives of acrolein may be present, but they could not be highlighted either by the detector of the chromatograph, or olfactory at the column outlet.

Received for publication in May 1973.

Summary
OCCURENCE OF ACROLEIN DERIVATES IN AN OFF-FLAVOURED RUM
A rum, which presented an off-flavour, has been analysed by gas chromatography and mass spectrometry. Two compounds were identified to 3-ethoxy propanal and 1,1,3-triethoxy propane, which are addition products of ethanol on acrolein. These compounds have already been identified in peppery ) whiskies, whose off-flavour originates also from the formation of acrolein during the fermentation. [original English language abstract from the end]

RESUMEN
PRESENCIA DE DERIVADOS DE ACROLEINA EN UN RON DE SABOR ANORMAL.
Un ron que presentaba un sabor anormal ha sido sometido a análisis por cromatografía en fase gaseosa y espectrometría de masa. Han sido identificados dos compuestos, el etoxi-3propanal y el trietoxi-1,1, 3 propano, productos de adición del etanol sobre la acroleina. Estos compuestos han sido encontrados ya en los whiskis « pimentados » cuyo sabor anormal procede también de la formación de la acroleina durante la fermentación.

RIASSUINTO [and now in Italian!]
PRESENZA DI DERIVATI DELL’ ACROLEINA IN UN RUM CON SAPORE ANORMALE
Un rum con sapore anormale è stato analizzato mediante gas-cromatografia e spettrometria
di massa. Si son trovati due composti : etossi-3 propanale e trietossi-I, I, 3 propano, prodotti d’addizione dell’ etanolo sull’acroleina. Questi composti sono stati già trovati in whisky «pepati) il cui sapore anormale è dovuto egualmente alla formazione d’acroleina durante la fermentaZIOIle.

Bibliography
KAHN J. H., LAROE E. G., CONNER H. A., 1968. Whiskey composition : identification of components by single-pass gas chromatograph-mass spectrometry. J. Food Sci., 33, 395-4oo.

KAHN J. H., SHIPLEY P. A., LAROE E. G., CoNNER H. A., IQ69. Whiskey composition : identification of additional components by gas chromatography-mass spectrometry. J. Food Sci., 34, 587-591.

MAARSE. H., ten. No EVER DE BRAUW M. C., 1966. The analysis of volatile components of Jamaica rum. J. Food Sci., 31 (6), 95 I-955.

MILLS. D. E., BAUGH. W. D., CONNER H. A., I954. Studies on the formation of acrolein in distillery mashes. Appl. Microbiol., 2 (II), 9-13.

SERJAK W. C., DAY W. H., VAN LANEN J. M., Boruff C. S., 1954. Acrolein production by bacteria found in distillery grain mashes. Appl. Microbiol., 2 (1), 14-20.
STENHAGEN E., ABRAHAMSSON S., Mc LAFFERTY F. W., editors, 1969. Atlas of mass spectral data.
Intersc. Publishers, 1, 275.

Guaranteed Dividends on Public Capital, and It Takes a Village

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Recently, a fascinating idea came across my desk as I’ve been following the new Diem 25 movement emerging in Europe. It describes a universal basic dividend as opposed to a universal basic income.

At DiEM25, we agree with the logic of a universal basic income. Critically, however, we believe that the money should not come from additional taxes or the government. It shouldn’t be people paying themselves; nor companies paying for something extra.

We think the money should come from a dividend, financed from the returns on all capital; a “public” percentage of companies’ profits, especially for companies that commercialise technology developed from public funding.

This hit me because I’m a collector of forgotten publicly funded science research. All these papers I keep putting up on the blog, they’re all public wealth that we collectively invested in, public intellectual capital. I even wrote a post titled Public Foundations for Private Spirits Companies. Most all companies could not exist without you the public financing the basic science they employ, but does that entitle us to anything from all our invested public capital, besides taxes? Due to rampant ideology, taxes are also moralistically in an immovable bind. No one seems to clearly understand taxes and their relationship to the public good.

We are stuck in a cycle where we think we can cut taxes to create new original prosperity which has been proven to not work. All the arguments are so congealed few that still believe in trickle down economics can be swayed on the issue. But what happens if we state it differently? If we start recognizing public capital, we can more clearly state that decreasing public capital, by decreasing taxes, basically taking away business foundations, will certainly not increase growth via original prosperity. This employs a whole new term, not in common economic discourse that is very dangerous to the GOP trickle down ideology.

We have been conditioned as a society to take our public capital for granted and the result has been unprecedented income inequality and a lack of original prosperity in favor of mere transfer prosperity (from the reservoir of public good which is basically public capital). We stopped taking account of our public capital and have let much of it evaporate such as in the misplacing of a century of distillation research despite a billion dollars of new distillery investment.

Every sector of American industry has their own parallel story. We either forgot where we put our public capital or it is used without attribution. Some sectors like pharma get downright nefarious where public capital is not so much used without dividend, but brazenly stolen and ownership held overseas.

If we collect mere taxes, we may foolishly pay our debts too aggressively even though that would show we don’t understand how money works. We are constantly tricked into thinking we cannot/should not issue debt to solve collective problems. Even more foolish is that we may evaporate it into the war machine and receive little in return. A dividend on public contribution to private enterprise is different. It returns back to every citizen so that they may privately do whatever they see fit. Public investment more directly translates to private freedom.

A universal dividend may remove the intellectual deadlock on taxes while recognizing our staggering American public wealth and not annoying people like the concept of a universal basic income from taxes.

It is not too apparent now, but many people are dragging their heals on automation to delay it’s dehumanizing, destabilizing potential. There is less need to fear it if you can be guaranteed via your citizenship and/or birthright to appropriately benefit. The U.S. could rapidly develop the second industrial revolution without grinding too many poor souls to dust in the mechanism as happened the last time around. We can socialize capital enough to create stability without robbing ourselves of the freedom of our private pursuits. If capital is not socialized to a degree, there will be no demand and we will see stagnation.

Another thing we desperately need to realize is that under internationalism some societies we repeatedly scoff at are producing incredible human capital and getting nothing in return as that human capital is pulled beyond their borders. The term internationalism might represent this natural path of least resistance while globalism might be attributed to deliberate policy to weaponize the phenomena (among others).

For example, Puerto Rico or say Greece produces many brilliant young engineers who aspire to build factories, but electricity costs three times as much as elsewhere so they have to leave to do it elsewhere. Well, mothers and grandmothers and neighbors, etc invested in those brilliant young minds. They are stakeholders in that valuable human capital that is crossing the border, but they are set up to get nothing while the U.S. mainland or often Germany reaps all the rewards.

We actually slander those countries in denial of the economics and leave them with unsustainable debt loads. The debt assumes population growth, but all there is population flight despite producing brilliant minds. Those mothers and grandmothers and neighbors get crumbing infrastructure and poor healthcare while we get the full rewards of their investment in human capital even though every single person agrees with the adage it takes a village to raise a child.

There is the myth of the lazy Puerto Rican only because their most industrious, which they likely produce at a higher rate than the mainland, are lured away. Puerto Ricans are American citizens. They go where they want and they start voting when they hit the mainland. We hypocritically attribute a responsibility to Puerto Rican debt because they are ethnically unique which we would never attribute to a bankrupt white city that saw huge population flight. If you are white and you flee debt ridden Gary, Indiana, you are not branded for life.

A lot of these things are the open secrets of the GOP. Much of the divide within that party is the elites being flabbergasted that everyone else is too stupid to see we’ve been robbing the world of their human capital and paying no dividend. Free capital! Capital! Free! They courted a few racist ideologues for votes, but now they’ve grown so massive they’re going to bring down large drivers of American prosperity.

American children, pretty much white American children, the millennials are turning out very different than previous generations. They lack tenacity and are known for entitlement because formative experiences and hardship were removed from their lives. As they come of working age, anecdotes and hard statistics are accumulating left and right that they cannot be counted on for the innovation society needs.

The immigrant, being more likely from a traditional 20th century style of upbringing, chock full of formative experiences will be increasingly valued. America will depend more and more on a work ethic and potential for innovation that only comes from human capital raised by that foreign village and it will continue to be immoral not to reward those communities.

The white American millennial generation is a human capital crisis. Undergraduate education has basically turned into high school and no real gainful employment can be had without a masters degree. It is basically taking four extra years to produce a kid who can produce for society as compared to a generation ago. If you shift the columns around that is like having everyone retire four years earlier than expected and thinking the pensions will be correctly funded. The economic ripples of these phenomena are only starting to be felt, but we are going to start seeing human capital be taken more seriously.

Irrational culture can keep the white American male dominant for only so long. Long term economics trends will catch up and numbers favor females and immigrants as actual performers. Public capital, human capital, and a universal basic dividend are concepts that will shorten the path to recognizing the trend. Diem.

Harris Eastman Sawyer, Frederick Felton, and the Free Alcohol Law

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This is probably the most exciting untold story in rum. When you read the script, imagine Gregory Peck as Harris Eastman Sawyer.

The committee met at 11 o’clock a. m.
Present: Senators Aldrich (chairman), Burrows, Piatt, Hansbrough, Hale, Daniel, Money, and Taliaferro.
Present, also, Frederick L. Felton, esq., of Boston, Mass.; Dr. Harris E. Sawyer, of Boston, Mass.; John B. Purcell, esq., of Richmond, Va.; Samuel A. Woolner, esq., of Peoria, Ill.; H. J. Kaltenbach, esq., of New York City, N. Y.; Peter J. Hennessy, esq., and others.

(Hon. John W. Yerkes, Commissioner of Internal Revenue, was also present during the latter part of the hearing.)

The committee thereupon proceeded to the consideration of the bill (H. R. 24816) “To amend an act entitled ‘An act for the withdrawal from bond, tax free, of domestic alcohol when rendered unfit for beverage or liquid medicinal uses by mixture with suitable denaturing materials,’ approved June seventh, nineteen hundred and six.”

STATEMENT OF FREDERICK I. FELTON, ESQ., OF BOSTON, MASS.

Mr. Felton. I am a distiller, Mr. Chairman, and have with me my chemist, Doctor Sawyer, who is thoroughly familiar with all the details of this matter. We desire a very simple amendment—that is, we would like the privilege of denaturing at the proof of 150° instead of 180°.
The Chairman. You make rum, I believe?
Mr. Felton. Yes, sir.
The Chairman. You are about the only maker of New England rum that is left, I think.
Mr. Felton. No; there are seven of us.
The Chairman. Are there as many of them as that?
Mr. Felton. There are seven of us left. I am perhaps the largest and the oldest, but there are seven scattered through the country— one in Covington, Ky., one in Portsmouth, N. H., one each in Newburyport, Charlestown, Everett, Somerville, and South Boston, Mass.
Senator Hale. Where is yours; in Newbury port?
Mr. Felton. No; not Newburyport. Mine is in South Boston. The Newburyport distillery is the Caldwell house.
We would like this bill, if possible—as well as all the amendments that are going through, which we do not oppose at all—to take effect upon its passage rather than wait until September, excepting that portion or it—which really requires more time for the Commissioner to make his regulations—In regard to the small distilleries throughout the country.
With your permission I would like now to introduce Doctor Sawyer and let him go into the details of the matter. I notice that the younger members of a business know more about it than the older men, who have laid aside a little bit and have attended less to the details.

STATEMENT OF DR. HARRIS E. SAWYER, OF BOSTON, MASS.

Doctor Sawyer. We are in favor of the passage of the act, but there is one amendment, Mr. Chairman and gentlemen, which we would like to see made. That is the insertion of a clause which will permit the denaturization at any proof that may be desired by the consumer, not lower than 150°.
The Chairman. What is the present limit—180?
Doctor Sawyer. One hundred and eighty. The reason why we ask for the insertion of this provision is that many of our customers, who use our material for industrial purposes, feel that it is a hardship on them to be obliged to use a material that has been redistilled to 180° of proof.
As you will remember, it was brought out in the hearings of this committee last spring that a certain amount of alcohol is used by tobacco manufacturers in the preparation of their leaf. That amount is not especially large in proportion to the amount of tobacco manufactured, but this use of alcohol is an essential feature in the manufacture of many brands, both of smoking and of plug tobacco—that is, both of the loose or granulated tobacco and of the plug tobacco.
Senator Hansbrough. Is it used in the manufacture or other articles than tobacco?
The Chairman. Do you mean to inquire whether rum is used?
Doctor Sawyer. No.
Senator Hansbrough. Only in tobacco?
Doctor Sawyer. Our industrial sale is solely to tobacco manufacturers.
Senator Hansbrough. All right; go ahead.
Doctor Sawyer. The part which the alcohol plays in tobacco factories is threefold. In the first place, it is necessary for the manufacturers to use alcohol in order to carry into solution many gummy materials that are added, for purposes of binding, to tobacco that is to be made into plugs. In the second place, they are obliged to use a considerable amount of alcohol in the lubrication of machinery and in cleansing floors. In the third place, they find that the presence of a certain amount of alcohol during the manufacturing processes tends to prevent the formation of mold on the somewhat moist tobacco leaves. They have been accustomed in the past to buy rum at 100° proof for that purpose; but they can equally well use a spirit at about 150°.
Senator Hansbrouqh. Can they not use it at 100°?
Doctor Sawyer. They would be able to use it at 160°, but it is desirable to hold the degree of proof down within certain limits, for this reason: In our crude molasses alcohol there are certain bodies not alcohol themselves; I will not pretend, even as a chemist, to say what they are, because we simply do not know. Their amount is so small that we are hardly able by chemical analysis to estimate their proportion. They are bodies of a waxy nature—something like cocoa butter, I think, and their bodies are left behind on the leaf when all the alcohol has passed off into the air. Now if we redistill our alcohol from a proof of about 150° up to the proof of 180°, to which proof we are obliged under the existing regulations to distill if we wish to denaturize, we take the wax out absolutely, and thus we despoil the material which we supply the tobacco manufacturers of a constituent which has been shown to have a very distinct value to them; I say again that we do not know what the waxy material is, so that we are unable readily to add anything of the sort to denaturized alcohol. But it keeps the tobacco from drying out, and it makes it smoke sweeter. If, several months after its manufacture, you feel of tobacco that has been treated with our 150° proof alcohol you will find that it balls together better, and that it packs better in a pipe than one that has been prepared with 180° proof spirit.
Furthermore, our crude alcohol carries at 150° a variety of odorous compounds, derived partly from the molasses which is our raw material and partly from chemical changes which take place during fermentation. These bodies are ethereal in character rather than alcoholic, and they impart to our crude spirit a disagreeable rankness which unfits it for drinking, even when it is reduced in proof, until it has been properly matured. Like the wax, they seem to be retained in the tobacco after the alcohol itself has evaporated, and they develop there an agreeable fruity character which fails to appear when a high-proof, purified alcohol is substituted for our crude, medium-proof product. They also resemble the wax in being removed from the crude spirit when we redistill it from the proof of 150° up to 180°.
Now, these fruity odors which develop on the leaf are considered to be very largely responsible for the character of certain brands of smoking tobacco; and while the manufacturers are very anxious to get the benefit of the remitted tax, to which they unquestionably are entitled under the act of June 7, they desire equally to hold the present character of their brands, and they wish, therefore, to be allowed to use the crude spirit, denatured at 150°, rather than the purer alcohol of 180° proof.
We, of course, are equally anxious to be allowed to furnish them the material which is most suitable to their manufacturing processes. We have teen building up this part of our business for the past twentyfive to thirty years and naturally wish to be able to hold it, especially as the consumption of rum as a beverage has been diminishing year by year. Our ability to retain it will depend, of course, upon our ability to supply a spirit of suitable character. We have made a large number of experiments during the past year to find out whether the tobacco manufacturers can, with advantage to themselves, use 180° proof spirit, and we find that undoubtedly it means a loss to them on account of the danger of changing some of the qualities of established brands.
I would like at this point to say that these experiments included tests of finished tobacco to ascertain whether any alcohol is retained therein. I found that practically none is so retained. In one case, the tobacco having been soldered up in tin cans, there were traces of alcohol present in the proportion of about one-half a gallon per ton of tobacco. In samples of plug tobacco no trace of alcohol could be detected.
Senator Hale. Let me ask you a question right there. You have stated what your market is. How does that apply to all these other establishments throughout the country? Are they situated just as you are about their market for their product?
Doctor Sawyer. Do you refer to the grain distillers?
Senator Hale. The rum distillers.
Doctor Sawyer. What we say of ourselves would apply equally to all of them.
Senator Hale. Is their market largely with the tobacco people?
Doctor Sawyer. No; I suppose that we have rather more business with the tobacco manufacturers than the other distillers do, as our business is larger than that of any other rum distiller.
The Chairman. What proportion of your product is sold for drinking purposes?
Doctor Sawyer. About one-third in this country and about one-third abroad. The balance is sold to tobacco manufacturers.
The Chairman. You sell rum abroad, do you?
Doctor Sawyer. Oh, yes; to the extent of a third of a million gallons a year.
Mr. Felton. Almost exactly half of what we produce goes that way.
Senator Hale. Do you think that proportion applies to these other establishments, as you have divided it?
Doctor Sawyer. I have not any means of knowing, sir.
Mr. Felton. I think I can answer that practically correctly. There are only about three, or possibly four, distillers who export any rum whatever. There is one concern which exports nearly as much as we do; one not nearly as much as that and one a very small quantity. The others export nothing at all. Theirs is all used for drinking purposes in this country.
Senator Hale. About what proportion is used for drinking purposes here in this country?
Mr. Felton. About as the doctor said—from 25 to 35 per cent, I should think, of all that is made.
Senator Hale. Not far from a third?
Mr. Felton. Not far from a third. Nearly 50 per cent, by the records of the Internal Revenue Department, is exported to Africa, Constantinople, Japan, Australia, and different places; and that, of course, goes out in bond.

Senator Hale. That is for drinking purposes?
Mr. Felton. That is usually used for drinking purposes, making cordials and the like.
Senator Taliaferro. Then there is not more than about 20 per cent that is used for the tobacco?
Mr. Felton. Yes; from 20 to 25 per cent, the difference, of course, between the 35 per cent used for domestic consumption and the 50 per cent for foreign consumption. These are approximate figures, of course.
Senator Taliaferro. That is a total of 85.
Mr. Felton. And about 25 to 35 per cent for the tobacco.
Senator Taliaferro. That would leave about 15 per cent?
Mr. Felton. Well, it is probably nearer 20 for tobacco. We can not get at accurate figures, of course, but that is as near as we can get at it. We have, perhaps, forty to fifty customers among the tobacco manufacturers who come direct to us; and then we think there are about fifty or sixty others that come to us through large dealers in spirits; and the balance we know nothing about. They probably go to other distillers, and some do not use it at all.
Senator Hansbrough. You do not pay a tax on the alcohol sold to be used in tobacco?
Mr. Felton. We do now. Oh, yes; on every gallon.
Senator Hansbrough. You do now?
Mr. Felton. Certainly; but under the new law if we make that rum 180° proof then the tax will be remitted if we denature the alcohol, as the Department now allows us to do, with a denaturant that the doctor will tell you about. We are already allowed to denature it and sell it to the tobacco people without the tax provided we put it 180° proof; but we want to save these odors the doctor tells about for the tobacco people by not making it at so high a proof.
Senator Hale. That is your main point—you want to use 150° proof instead of 180°?
Mr. Felton. That is our main point; practically, our only point.
The Chairman. On the ground that the tobacco manufacturers can buy it at 150° and could use it to better advantage than if it was 180°?Mr. Felton. It retains the odors they desire.
Senator Hale. The 150° proof would assimilate better with their manufactures than the 180°?
Mr. Felton. It gives them the odors they want.
Doctor Sawyer. And this other quality that I spoke of, the waxy substance.
Senator Hale. Yes.
Doctor Sawyer. The wording of the modification which we would suggest would be something of this sort: We would insert after the words “domestic alcohol” in lines 7 and 8 the words “of not less than one hundred and fifty degrees proof.” That would permit denaturalization down to that point, but not below. We will submit to the committee a little later a draft showing exactly what we desire the first section of the bill to be.
We have felt that there was no reason why we should not be allowed to denature at as low a proof as 150° under the existing law of June 7, 1906. The Revised Statutes specify regarding alcohol as follows:

Sec .”1248. Distilled spirits, spirits, alcohol, and alcoholic spirit, within the true intent and meaning of this act. is that substance known as ethyl alcohol, hydrated oxide of ethyl, or spirit of wine, which is commonly produced by the fermentation of grain, starch, molasses, or sugar, including all dilutions or mixtures of this substance, etc.

According to section 3248 of the Revised Statutes, therefore—and this, so far as I am aware, is the onlv place where alcohol is defined in our law—alcohol is alcohol, regardless of its strength, whether the latter be 150° or 180°. The act of June 7, 1906, reads, in part, as follows:

That from and after January first, nineteen hundred and seven, domestic alcohol of such a degree of proof as may be prescribed by the Commissioner of Internal Revenue may be withdrawn from bond without the payment of Internal-revenue tax for use in the arts and Industries, provided said alcohol shall have been mixed In the presence and under the direction of an authorized Government olficer, after withdrawal from the distillery warehouse, with methyl alcohol or other denaturing material or materials or admixture of the same, suitable to the use for which the alcohol is withdrawn, but which destroys its character as a beverage and renders it unfit for liquid and medicinal purposes.

Therefore we requested permission to denature for our tobacco customers with tobacco extracts at proofs as low as 140° or 150°. The Commissioner has granted the first part of our request, but he says that in his belief he is not authorized under the law to establish so low a limit as 150°. In his opinion, alcohol is a stronger material, in spite of the fact that the wording of section 3248 would lead one to say that any spirit of any strength down to or below 100° of proof is alcohol within the meaning of the law.
What we now want, therefore, is an explicit statement in this bill that we shall be permitted legally to denaturize as low as 150°. The only objection which could be made to our denaturization at that low proof, in my belief, would be one to be based upon the chance of fraud. Now, I do not see how any fraud could possibly arise, because the denaturant which we are going to use is just as efficient at one strength as at another. The manufacturer who had bought alcohol denatured by our process at 180° would be able the moment he received it to add water in his factory to bring it down to any proof at which he wished to use it; and it makes no difference whether that water is added by him after the alcohol comes into his possession or whether it is left in there from the time that it is made by us.
Senator Hale. What is your denaturing agent?
Doctor Sawyer. A mixture of two aniline colors and a certain proportion of nicotine—nicotine being a body of nauseating character, when taken in sufficient doses, and being at the same time a characteristic element of tobacco, so that we are not introducing into the alcohol anything which would not normally be present in the tobacco to which it is added.
Senator Hansbrough. What is the cost of it?
Doctor Sawyer. Of the nicotine?
Senator Hansbrough. No; of your denaturant.
Doctor Sawyer. The cost figures out about 1 cent for every gallon of strong alcohol; about one-half a cent per proof gallon.
Senator Hansbrough. That is a cheap denaturant.
The Chairman. Does the nicotine you use come from tobacco?
Doctor Sawyer. It is extracted from tobacco stems. They extract it in a state of almost chemical purity in some of the Louisville factories where they work up tobacco refuse. We propose to buy it as chemically pure nicotine, add a certain amount of it to the requisite amount of aniline dyes, and then add sufficient water to bring it to a definite strength; and then 1 per cent of that, by volume, is to be added to 100 parts of alcohol.
Senator Hale. Has this denaturing agent, this composite agent which you use, been submitted to the Commissioner of Internal Revenue?
Doctor Sawyer. Yes, sir; and approved by him.
Senator Hale. And approved by him?
Doctor Sawyer. And approved by him and his chemist. Senator Hansbrough. Let me ask you whether that denaturant can be manufactured in unlimited quantities?
Doctor Sawyer. Yes, sir.
Senator Hansbrough. So that it might be used as a general denaturant by everybody?
The Chairman. You could only use it, I suppose, in tobacco manufacture, on account of the nicotine. They could not put that into everything, I imagine.
Senator Hansbrough. You could put it into alcohol that was to be used as an illuminant, or for fuel purposes, because the object is to make it undrinkable.
Doctor Sawyer. It could be used.
Mr. Felton. It would make it decidedly undrinkable.
Senator Hansbrough. That is the cheapest denaturant I have heard of.
Senator Hale. And unsmellable, and everything else.
Mr. Felton. It does not smell very bad.
Senator Hale. It does not?
Mr. Felton. The doctor has a sample here.
Doctor Sawyer. Here is a sample which has been denatured with this material [exhibiting sample of denatured alcohol to the committee].
Mr. Felton. Everything that we desired has been approved by the Commissioner except the one item of proof.
Senator Hansbrough (referring to sample of denatured alcohol). Has that 1 per cent of your denaturing agent in it?
Doctor Sawyer. That has 1 per cent of our denaturant.
Senator Hansbrough. This is the double strength—180°?
Doctor Sawyer. Yes, sir. The object of adding the nicotine is, of course, to make the alcohol undrinkable. We have in what would be an ordinary drink an amount of nicotine that would make a man good and sick, and we put in, in addition to the nicotine, the aniline colors, to warn a man that it is not something that is intended to be drunk.
Senator Hansbrough. Do you not regard that as the cheapest denaturant that is being used or likely to be used?
Doctor Sawyer. I think that is the cheapest, and I think that in many respects it is most nearly an ideal denaturant I think that it is fully as efficient as any of the general denaturants that have been recommended, in spite of the fact that under the regulations as they now exist this is permitted to be used only as a special denaturant where records are kept by the manufacturers of the amounts bought and used.
Senator Hale. All that is regulated by the Commissioner?
Doctor Sawyer. All that is regulated by him, sir.
The Chairman. Is that all? We will have to go ahead, because we have not very much time.
Senator Hale. Yes; I think we understand the gentleman’s position.
Senator Burrows. What do you say about wood alcohol as a denaturant?
Doctor Sawyer. I think myself that wood alcohol is not nearly so efficient a denaturant as this material, because, in my opinion, wood alcohol, when mixed in the proportions called for under the regulations, does not impart nearly the nauseating character to the denaturized alcohol that this proportion of nicotine would. It makes it smell worse; it gives the man who might drink it more warning, perhaps; but the final effect upon the drinker would not be nearly so pronounced as that of our denaturing agent.
The Chairman. We will give you and Mr. Felton a copy of this testimony, and you can extend it or enlarge it as you see fit. Perhaps we had better hear the ether people now. We would like to have the Commissioner here when Mr. Woolner and his friends are heard upon the bill and their objections to it. Perhaps we had better hear the ether people next.

New England Rum, Briefly Too Fine To Drink

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Letter from the President of Felton & Sons (Inc.), Boston, Mass.

Washington, D. C, May 12, 1921. Hon. Andrew J. Volstead, Chairman Judiciary Committee, House of Representatives, Washington, D. C.

Dear Sir :

As rum distillers at Boston, Mass., now engaged in the production
of high-proof rum for industrial uses, we beg to request that such correction be made in the second paragraph of section 2 of H.R. 5033, now pending before your committee (p. 2, lines 3 to 14), as will avoid interruption of our necessary production of industrial rum.

The rum which we manufacture is produced at from 150 to 160 degrees or proof; that is, the rum contains from 75 to 80 per cent of alcohol by volume. The rum is not, however, fractionated to the point where it contains from 94 to 95 per cent of alcohol by volume, which is the usual strength of commercial alcohol. Rum for the purposes for which we manufacture it must retain some of the congeneric flavor which would be fractionated out of the product if the extreme fractionation were attained.

This rum is exclusively used domestically for flavoring tobacco; that is, the rum is sprayed over the tobacco, the alcohol evaporating and leaving in the leaf during the course of manufacture the desired rum flavor. This is one of the ancient tobacco flavoring processes, and our company has furnished rum for this purpose for many years—long antedating prohibition.

The rum for domestic uses is denatured with nicotine and rendered unfit for beverage consumption, and this denaturing work is done in our own denaturing bonded warehouse adjacent to our distillery.

What we are particularly concerned about is, however, our right to manufacture this character of rum not only for domestic use, denatured as stated, which we do not understand is affected by H. R. 5033, but particularly our right to manufacture this product for exportation.

We have long enjoyed an export trade in this character of rum with foreign tobacco manufacturers, who purchased this rum from us on account of its particular character for the flavoring of tobacco abroad in the same way that our domestic manufacturers used it. We do not, however, denature this export rum, as it is exported free of tax. and denaturation is not necessary to secure this tax-free export privilege. Our foreign buyers are accustomed to using this rum undenatured, or else denatured in their own country under the local requirements. Our foreign customers object strenuously to the rum denatured with nicotine and would find other sources of supply if we were unable to furnish them the undenatured rum which they have been accustomed to receiving.

You will realize that this rum is exported for nonbeverage and industrial uses, and no question of this particular kind of rum being used for beverage purposes in foreign countries can arise. Rum at cheaper cost than ours can be secured by the foreign countries for beverage purposes, and rum of the cost and character of our product could not, as a commercial proposition, compete for beverage purposes, even though the foreign tobacco manufacturers, who are customers, were inclined to consider our export flavoring rum from a beverage standpoint. Of this there is no possibility, because our foreign customers are large and responsible tobacco manufacturers, who buy our product solely for use in the preparation of their tobacco.

For your further information, practically our entire list of foreign consignees are subsidiaries of the British American Tobacco Co., and we know that they use this rum exclusively in their foreign tobacco factories. It may well be said that the operation to which we refer would in no way be interfered with by the second paragraph of section 2, but it would be a disaster to us, if under any circumstances, we were not permitted to continue our production for export purposes under the circumstances above stated.

An amendment which will make this clear and certain would consist of the words “including rum for industrial purposes” after the word “alcohol” in line 5 of page 2. This would make the exception read, “save alcohol, and rum for industrial uses.”
Respectfully,

Felton & Son (Inc.).
Boston. Mass.,
Per Herbert L. Felton,
President and Treasurer.

 

Thirty Years of Rum Technology at INRA

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Trente ans de travaux en technologie rhumière à l’Inra-Antilles-Guyane

[A variation of this paper exists here, possibly presented differently for a conference]

This wonderful French paper came across my desk a while ago and it may finally be time to tackle it. It contains the history of the last thirty years of rum history (starting 1970) contributed by many great scientists.

Many times I’ve described rum history as starting with W.F. Whitehouse and then the torch being successively passed through the generations. The torch has wandered around a lot but basically for the last thirty or forty years been held by the French speaking parts of the tropics.

The paper summarizes their investigations and achievements and provides a stunning bibliography to pursue further (I’ve already dug into a lot of it over the years).

I’m going to try and translate it with Google to see if it can launch some ships. I’m going to take some liberties to smooth the translation so do not rely on it and please pursue the original work linked above.

Thirty years of work on rum technology at Inra Antilles-Guyane: Thirty years of research on rum technology

by Fahrasmane L., Parfait B.

Abstract: Thirty years of research on rum technology at INRA Antilles-Guyane. The rums produced in the French overseas Departments are marked by their strong and original aromatic character. Thirty years of research conducted at INRA Centre Antilles-Guyane allowed the inventory of the bacterial flora and the yeast strains involve in fermentation media, and get out of a manner of production mainly based on empirical practices. The collected data have contributed to control the vagaries of fermentation and at the same time to control the acidity of the distillates, resulting in better control of the regularity of rums quality. Among main results there were: a commercial yeast strain selected for the rum distillery, the first in the world for this purpose, and processes developed for waste waters remediation by anaerobic digestion producing also energy.

Keywords: rum, microbiology, sugarcane, fermentation, yeast, bacteria, waste waters, waste waters treatment, composition

I have heard of this Sacharomyces yeast, but was not aware it came from this French effort.

Introduction:

In the three islands French overseas departments, the production and processing of cane to sugar (Saccharum officinarum) remain a significant part of their respective economies, sugar production and the production of traditional rums.

The term “rum” is generic and refers to alcoholic distillates from the distillation of fermented must, prepared from sweet products derived exclusively from cane sugar: juice, syrup, molasses. Traditional type rums are characterized by their aroma. This type of production uses the empirical know-how of producers. To keep pace with the new patterns of consumption, changes in distribution and need to negotiate with the administrative and political structures involved in the environment of this sector, producers have had an urgent need for technical data and of production processes and products. This has resulted in a need for research that has been taken into account since 1970. Since 1972, INRA within its Center Antilles-Guyane has operational resources that enabled work to be carried out for this sector of activity.

Their idea of empirical parallels the idea of practical that we saw in American whiskey production. American whiskey got a little bit of help from the IRS’ excise officers, but the move to guided traditional processes did not exactly happen with government help. Here, private companies are given a very strong public foundation of basic science to advance on.

Sugar cane is an agricultural resource that, on a global scale, is subject to creation for a little more than a century. However, there has not been cane specially designed for the processing of rum.

A very interesting admission. When rum becomes more of a primary product and less of a byproduct it becomes possible to find out which varieties have the most extraordinary aromas. Cane varies in color a lot and there are a lot of unique aroma precursors correlated to skin color similar to wine.

The manufacture of traditional rum involves yeasts and bacteria that convert sugar into ethanol and co-produce compounds with aromatic properties. These strains are often genera and species identical to those found in other agro industrial fermentations (Saccharomyces, lactic acid bacteria). Schizosaccharomyces is a spontaneous genus, singular, and obligatory in the production of traditional rum of great aroma type. Ecosystems which constitute the fermentation media of rum production, have physicochemical conditions remarkably different from brewing, oenology or milk processing environments. The knowledge that could be generated on these micro-organisms, from tropical environments, is scientifically interesting for modern microbiology.

Extra fascinating and here we see strong language promoting Schizosaccharomyces for fine rums. The idea that this basic science could teach lessons to other biotech processes is very exciting.

Traditional Rhums

Their diversity as well as historical, cultural and fiscal reasons make them appreciated. The dynamic stronger marketing of rums of all types makes the French aware that the road of rum goes around the world. As a result, traditional production will have more and more to face, in its markets of choice, to world production. Hence the need for it to produce knowledge in order to be able to value its products, to acquire new technical understanding making it possible to have marketing arguments, which guarantee the reputation of the most known.

Marketing arguments is a much more important concept than anyone has realized at the moment. Lost Spirits jumped the gun and tried to make marketing arguments without doing any due diligence and though it worked out for them overall, it exposed them to a lot of weakness. A lot of my rum history explorations are based on collecting and exposing marketing arguments that can support a fine rum category.

Traditional production has long been characterized by the use of cane or molasses, without specification of the quality of these raw materials, as well as by the use of non-sanitized dilution water taken from the natural environment (watercourse, groundwater). The fermentation was often spontaneous. This resulted in a high variability of the quality of the products, some of which were characterized by high volatile acidity and off-flavor, abnormal tastes (acrolein, allylic alcohol, etc.). Production was thus confronted with the quality of raw materials, and of a random mixed fermentation.

I would love to learn more about the abnormal tastes so we can compare INRA influenced rums to those of Cape Verde.

Implementation of the research approach

French West Indies rum production has always been marked by the aromatic character of its products. At the beginning of the last century, attempts to integrate into the production new practices from industrial microbiology (pure culture, mother-cell, strain selected), had failed, as productivity gains had been favored. Products had become aromatically neutral. Most producers returned to 1920, to mixed fermentations. However, the passage from the still to the Creole column, with the aim of improving productivity gradually took place between 1818 and 1865 without any recognition that the products produced by the pot still are of better aromatic quality than those obtained with a distillation column.

Pure cultures are even plaguing other spirits and my hunch is that they’ve eroded the quality of tequila. I don’t know if 1920 is a significant date or just an expression here. And I’ve never heard of the column still referred to as a creole column. Very cool. We are seeing the return to guided to traditional processes.

The aromatic character of traditional rums is a determining factor in their culinary use. In France, in particular, nearly 2/3 of the rum is singularly used as an culinary ingredient. Within spirits, the extent of this form of use of traditional rum is singular. For the time being, in manufacturing and marketing, there has been no consideration for this specific type of use. It is interesting to note that approximately 10,000 hectoliters of pure alcohol of rum, a highly aromatic flavor, are marketed annually as a culinary ingredient, exclusively for culinary preparers, with particularly low taxation. This is a path that needs to be revitalized. To do this, there is an acquisition of knowledge to be carried out on the microbial ecology of the manufacturing rum of great aroma. It is a complex and spontaneous ecosystem that we hardly know how to reproduce. The failure many attempts to reproduce it bear witness.

I think by culinary use they mean bulk highly flavored rums for larger scale food production like making tons of pâté or flavoring tobacco. Potability parallels Angostura bitters so they are looking for the same tax break. It is admitted that they hardly know how to produce these high ester / grand arôme rums which are likely concentrates such as Jamaica used to make.

The need to control the quality of this aromatic production, and to objectify the descriptors of products, led the professional rum groupings, from Guadeloupe and Martinique, to research and development. It is in response to the expression of this need that INRA has put in place research work. P. Dupuy, Director of Research at INRA, created a two-week mission to the Caribbean in March 1970, with the main aim of a scientific orientation to a future INRA laboratory, working for the rum industry. In his mission report, he proposed a research program for “a study on the fermentation of rum”. The purpose of this was agricultural rum and industrial rum. The proposed objectives were:
• «… better know the flora responsible for fermentation and in particular the role of bacteria».
• determine «the conditions that will increase yield and esters, and decrease higher alcohols and aldehydes».

As early as 1972, A. Parfait began work at the Research Unit in Product Technology Plants of the INRA Antilles-Guyana Center.

It looks like they are creating an agricultural experiment state just like Jamaica had and just like the work of Arroyo. They were probably not exactly reinventing the wheel but seeing it first hand for themselves so they could consult. Tons of work was available such as Studies on Rum, but faith in it had likely eroded. It was also pre internet and hard to assemble materials. No French person wanted to create a million dollar company relying on a pamphlet of Puerto Rican science from the 1940’s.

First Approach Work

These have been based on: esters which are deemed to be quality compounds of spirits, the problem of abnormal taste which existed on the products of the time, and the necessity of drawing up a state of art.

The composition of the traditional rums in volatile esters of higher fatty acids was the first published results (Parfait et al., 1972). Although the mixture of these compounds is not the complete characteristic aroma of rums, it participates in their qualities. The factors presented as distillation at a low rate of rectification, the addition of fermentation medium, the distillation of turbid musts and the use of selected strains of yeast.

I think the idea here was that if you targeted esters, you’d get the other stuff you wanted. Now, my hunch is that if you target rum oil, you’ll get all the esters you want when you consider how all the processes and consideration align. By turbid musts, I think they mean centrifuged and defecated cane juice such as Arroyo discussed and we can see in the comparisons of Martinique to Cape Verde.

The presence of acrolein derivatives in an abnormal flavor rum (Dubois et al., 1973) was the subject of which concluded that the observed bad taste was due to the presence of acrolein in fermented must. Parfait and Sabin (1975) gave an update on the main operating parameters of the technology ruminant, yeast flora, and the analytical composition of the main types of traditional rum that are: agricultural rum, industrial rum, grand arôme rum, and syrup rum. The authors concluded that «this traditional production of the French West Indies gives an important place to the art of the operator». These authors added that the determination of fermentation parameters (temperature, flora, distillation apparatus, complementation, etc.) did not guarantee obtaining a given product in conditions. So there was no control of the process.

I think this shows their complaint with the state of the industry they found. Distillers were too practical. They had no chemical or biological control so their products varied all over the place week to week. The acrolein idea is very important and I’m going to pursue it. It may plague some of the Jamaica rums or even be an unintended feature. It only becomes a flaw when we can attached regrets and miss opportunities to it.

In 1975, an international symposium on rums was organized by INRA and the Association for Promotion of Agricultural Industries was an opportunity to take stock of the skills available and the approaches developed in various parts of the globe in the area of ​​rum technology. These first established milestones identified that traditional rum-problems of non-quality, which went beyond the problem of abnormal products of the time. It was clear that there was a lack of apprehension of health problems, raw materials, dilution water, and industrial facilities. Beyond elements that regulate rum, it was necessary to identify health data, microbiological and fermentation processes, which would make it possible to produce bad taste and off-flavor, while leaving room for diversity.

The symposiums is very interesting and I did a ton with it such as discovering Olbrich. By health problems I think they primarily refer to pollution and not copper poisoning or anything like that.

Research paths were then developed gradually with a view to identifying means of control, the sources of non-quality of traditional rums and control of the regularity of production. They concerned:
• the microbiology of fermentation media, both for yeasts and bacteria, rum chemistry and metabolic pathways,
• the operating conditions to control the appearance of off-flavors.
• processes for the treatment and valorisation of effluents from rum- land,
• the chemistry of rums in connection with the microbiology of fermentations and the maturation of distillates.

Metabolic pathways and microbiology become very important here. These people weren’t just biologists or chemists, they were microbiologists. They could ask and answer questions that even Arroyo could not. Arroyo suspected S. Pombe produced more rum oil, but microbiologists could actually tell us how which could be tied to more specific actions on the part of the distiller. They could even look closely enough to tease out the nature of complex off aromas.

Control of non-quality

Raw materials, molasses and sugar cane juice are not sterile and fermentation are neither sterilized nor pasteurized. With dilution water, raw materials host a bacterial flora that develops during the fermentation for rum production. The work in bacteriology have shown that in rum technology there is a varied bacterial flora (Fahrasmane and Ganou-Parfait, 1998).

In the aromatic character of traditional rums, the bacterial flora plays a decisive role; their elimination leads to neutral products, this is the case in the production of light rums. Beyond of a certain threshold, bacteria can be detrimental to the quality of the products. Without searching to eliminate bacteria, it will be interesting to identify the conditions, mechanisms of onset for negative factors to rum, resulting from bacterial activity, in order to propose solutions for control.

Bacteriology of dilution water

For the composition of the musts, water is supplied. The volumes used represent between half and 4/5 of the production. It comes from rivers or groundwater. A study on the bacteriology of distillery production waters in Guadeloupe was carried out (Ganou-Parfait et al., 1991). The bacteria of dilution waters are anaerotolerant germs (106 cfu / ml): coliforms, fecal streptococci, Clostridium, sulfato-reducing bacteria (BSR) (103 c.f.u./ml). Their number increases with the rate of mineralization of these waters. The flora of the waters, particularly rivers, grows seriously in bad weather. Increasingly, distilleries are equipped as a water treatment plant; it is a necessity to manage the health risk from the dilution water, in particular with strongly water mineralized or in rainy weather. The health status of manufacturing waters has improved.

This reminds me when I covered Scotch, pond water, and floaties.

The volatile acidity of wines and rums.

Three main factors affect the nature and quantities of volatile acidity of rums (Fahrasmane et al., 1983):
• fermentation agents,
• the temperature of fermentation whose rise increases the volatile acidity,
• the degree of distillation.
The volatile acidity of fermented media and distillates is related to the activity of the yeast that occurs during alcoholic fermentation. The bacteria present in the media fermentation contribute to the volatile acidity pool; in particular during fermentation accidents, the volatile acidity of these media is increased. The slowing down of the fermentation rate, which may result in a cessation of fermentation (Ganou-Parfait et al., 1991).

The consumption rums usually have a volatile acidity which varies between 1 and 5 ml/l (ml/ l). This parameter doubles in aged products. In acidic rums, the volatile acidity varies between 10 and 20 (ml/l).

The level of volatile acidity and the proportions of its components appear as indicators the presence of bacteria and their activity during rum fermentation.

So when fermentation is temperature controlled to ideals, volatile acidity implies flavor and implies contribution of bacteria to aroma.

The bacteriology of musts.

Sugar cane juice, which is the raw material of agricultural distilleries, contains germs (Ganou-Parfait et al., 1991). Micrococcus, Corynebacterium, Bacillus are the most common assets. They come from soil, sugar cane stalks, air and installations. We find there also aerotolerant anaerobes, capable of using the lactate produced by Leuconostoc, Lactobacillus and anaerobic Clostridia. Lactic acid bacteria dominate.

In molasses, mainly lactic bacteria and sporulates (Bacillus) are found.

The populations of distillery musts are very varied. We find there:
• Micrococcus in sugar cane juice (Ganou-Parfait et al., 1988). These are bacteria of the soil, which is also found on sugar cane stalks, in distillery wort; they can be divided into three types. They are preferential: whereas anaerobiosis is not yet established, their populations reach 105 cf. / ml in musts. Their activity is detrimental to the quality products because they produce acrylic acid and allyl alcohol in rums based on cane juice.
• Bacillus in sugar cane juice musts (Ganou-Parfait et al., 1987). They come from canes attacked by rodents (rats), and dug by galleries by insects borers. The strains remain anaerobic. They produce volatile fatty acids from the lactate. They have the characteristic of forming sails at the surface of the tanks at the end of the alcoholic fermentation. These sails seem to protect open-pit tanks from the development of bacteria.
• Corynebacterium (Lencerot et al., 1984) and Clavibacter. They come from the sugar, especially when its health status deteriorates. These bacteria degrade glycerol, which produces secondary alcoholic fermentation by yeast, acrolein (2-propenal) and 2-propenol. These reactions give rums with a pungent taste.
• Clostridium which are anaerobic germs. The improvement of the sanitary quality of manufacture has made it possible to decrease the population of Clostridium telluric. Clostridia play an important role in the manufacture of rum great aroma, with in particular Clostridium saccharobutyricum. Sugar cane juice media frequently contain Clostridium butyricum and Clostridium bifermentans. In molasses based media, also some species of clostridia.
• Lactic bacteria, the number of which varies between 107 and 108 c.f.u./ml, at the beginning of fermentation, whether in musts based on cane juice or molasses. 80 to 90% of strains have anaerobic behavior. It contains homofermentary bacteria and heterofermentative. Their activity generates lactic acid and polysaccharides. Bacteria lactic acid constitute the bulk of the bacterial flora of molasses-based musts; while is more varied in those based on cane juice.

There is just so much in here. First we find that rat eaten canes pick up rodent bacteria that may be aroma beneficial. It is also an ancient European invasive species influence on the terroir. The protective nature of lactic bacteria also makes rum seem more like sour mash whiskey and we get more explanation of surface films and how they protect fermentations. Basically I’m going to get Boston wharf rats to eat cane and infect it with their bacteria for my New England rum.

An approach to the dynamics of the various bacterial species during the fermentation cycle it can be concluded that, in particular, sugar cane juice lactic preference of musts, before the alcoholic fermentation takes place (Ganou-Parfait et al., 1989). Work in progress aims to model this “co-culture”, in order to enhance it technologically. Indeed, the current practice is to acidify the musts at the beginning of fermentation by supply of sulfuric acid. By directing microbial ecology, it could be lactic acidification which would then allow alcoholic fermentation by yeast, in the usual pH range which protects the environment from the development of bacteria damaging.

Here I think they are proposing trading sulfuric acid which eventually became traditional for dropping pH for lactic acid which can better protect a ferment from bacteria without dropping the pH as low. Definitely need that paper.

Alcoholic fermentation of rum

The main unit operations carried out during the production of rum are the extraction, fermentation and distillation. There are losses at all these stages. Losses during the fermentation are the most important. Measurements of fermentation yield in fermentation (Fahrasmane, 1991).
The results are as follows:
– Yield Gay-Lussac 0.67 l AP / kg glucose,
– Pasteur yield 0.61 l AP / kg glucose,
– Optimal theoretical efficiency 0.59 l AP / kg glucose,
– Yield on molasses 0.52 l AP / kg glucose,
– Yield on cane juice 0.47 l AP / kg glucose,
– Yield on syrup 0.40 l AP / kg glucose.
In a beet molasses distillery, with a yeast per stock, the fermentation yield is of 0.58 l AP / kg glucose (from Miniac, 1988). While improved performance was not a priority, after the problems of non-quality had been resolved, the professionals improvements in performance. One of the pathways explored is the search for yeast strains selected, adapted to the fermentation of sugar cane products (Fahrasmane et al., 1986)

I think the measure meant there is liters of pure alcohol produced (AP) per kilo gram of sugars as glucose.

Schizosaccharomyces of rum distilleries have been isolated and collected in our Unit (Fahrasmane et al., 1988). Their taxonomic study showed that there were essentially Schizosaccharomyces pombe (90%), some S. malidevorans (8%), and S. japonicus (2%). A study on their use in rum technology was carried out (Ganou-Parfait and Parfait, 1980). This type of yeast may under certain technological conditions, have a productivity in alcoholic fermentation, equivalent to Saccharomyces cerevisiae. The aromatic profile of secondary compounds products is very different from that of Saccharomyces.

Schizosaccharomyces and the bacterial complex, rich in Clostridium, which accompanies it in the fermentation of the flavoring rum constitute for the moment an ecosystem, giving products singularly rich in aromatic properties. Producers know at best how to reproduce ecosystem without controlling it. There is knowledge to generate, in order to master it and better value.

I think what he means at the end of this passage, is that they know how to start the ferment but not exactly how to control it. In the days of the Jamaican experiment station, it wasn’t confidently even known how to start these ferments.

A collection of strains of Saccharomycetaceae of rum distilleries was constituted (Parfait and Sabin, 1975; Fahrasmane and Ganou-Parfait, 1998). From this collection, a study was undertaken in to select yeasts for the rum. This work culminated in 1997 in the selection, world, of the first commercial strain of rum distillery yeast: DANSTIL EDV 493 (Vidal and Parfait, 1994), a Saccharomyces cerevisiae marketed, in the form of active dry yeasts, by Lallemand. This selected yeast allows an improvement of the fermentation yields and of the productivity, by means of a seeding arrangement, in relation to the usual conditions cutting. One of its peculiarities is not to be as affected as the other strains of yeast, used as make-up yeast, at temperatures around 35 ° C which can be measured in the vats of rum distillery.

So it has heat tolerance and “killer yeast” characteristics that prevent the growth of wild yeasts.

The sugarcane stem is wrapped with a cuticular layer of wax. The wax is concentrated in the defecation sludge from the sugar. A fractionation of these sludge was undertaken. Steroids, including stigmasterol and sitosterol have been isolated. These have been added to media fermentation in order to study their action on the fermentation behavior of yeasts. when the addition of these steroids results in an increase in ethanol production, compared with a control medium without the addition of steroids. Bakery yeast already relatively rich in sterols is much less sensitive to the intake of steroids (Bourgeois and Fahrasmane, 1988).

I don’t completely understand what is happening here.

Secondary products of alcoholic fermentation

Glycerol is a by-product of alcoholic fermentation, frequently present in quantities, in the rum fermentation medium. It has the particularity of being consumed by bacteria (Fahrasmane and Ganou-Parfait, 1998) (Micrococcus, Bacillus, Lactobacillus, Leuconostoc, Clostridium) by producing compounds related to the bad tastes of rums: acrolein, propenol 2 and sometimes acrylic acid. These compounds are indicators of disorders bacteria, which must be remedied, for example in molasses-based production, avoiding fermenting conditions which are favorable to the formation of glycerol (18), and by working in sanitary conditions which inhibit the action of an overabundant contaminating bacterial flora.

At the end of a thesis work on «the formation of short fatty acids and higher alcohols by of yeasts of a rum distillery», Parfait and Jouret (1980) showed that the choice of the species and of the strain of yeast is crucial in the quantitative and qualitative control of the production of short fatty acids and higher alcohols. It appears that in the cane juice medium there is formation of propionic acid; the composition of organic acids (citric, aconitic and malic) of the juice appears production. It is necessary to put this result in conjunction with the singular wealth of traditional rums to propionic acid in particular, and more generally to short fatty acids.

From a methodological point of view, we have been interested in ethyl 2-methyl-butyric acid, identified by some authors as a characteristic of rums (Fahrasmane et al., 1985). This work showed that it is more the quantities of this acid of bacterial origin which are singular, because in the end it is found in other stuff as well.

Some translation errors obscure the specific significance here. I’ll have to track down those papers. A lot of this considers what specific fatty acids and esters most characterize rums.

Rum Chemistry

The work carried out in chemistry of rums, beyond the esters, involved chemical compounds or chemical families that are major in non-alcohol (higher alcohols), or that are sensitive in terms of product quality.

Rum contains a greater variety and greater amounts of organo-sulfur compounds than other spirits (Fahrasmane et al., 1989). According to Leppanen et al. (1979), rum is the only spirits containing dimethyl sulphide. The activity of sulfate-reducing bacteria in the media fermentation would be partly at the origin of all these compounds. The composition of sulfur-containing elements in sugar cane and the addition of ammonium sulphate and sulfuric acid, would provide a substrate for sulfate-reducing bacteria in musts.

I definitely need this paper because I’ve heard anecdotal stories about cane high in sulfur that I’ve never been able to make sense of.

Downstream of the distillery, the methanisation of effluents poses the problem of a precarious balance between methanogenic and sulfato reducing flora. The organo-sulfur fraction of rums deserves a thorough and systematic study, because it has an analytical and organoleptic interest for the characterization of rums.

The dosage of formic acid in aged or non-aged rums shows that the level of formic acid in of traditional rums is within the range of figures found for other spirits. Also, the intervention of bacteria leads to a significant increase in the level of formic acid in rums (Jouret et al., 1990a). This acid is quantitatively more important in molasses rums than in those based on sugar cane juice.

Some alkylpyrazines of rums appear to be able to differentiate molasses based white rums from those of cane juice. Indeed, 2 methyl pyrazine, 2 – 5 methyl pyrazine and 2 – 6 dimethyl pyrazine are absent from agricultural rums, although they are clearly present in those based on molasses (Jouret et al., 1990b).

Ethyl carbamate or urethane is a molecule known to be carcinogenic that can be found in rums. The North American market has adopted an upper limit for the presence of this compound in the rums, which is 125 μg / l. This substance may originate from fermentation, particularly in urea-containing media, which is not the case for distillery media, but it can also be formed by purely chemical reaction during and after distillation.

Rums have never been known to be particularly rich in ethyl carbamate. Its presence, beyond the defined threshold, is a concern for producers who want to export, in particular, to North America; some rums are exempt but others are not, can now have explanation. The quantities measured are up to 2,500 μg / l. There is therefore knowledge to be generated on the determinism of the appearance of ethyl carbamate.

I don’t think I’ve ever posted on ethyl carbamate though I’ve read quite a few papers. My theory is that it is a chemical trade barrier. It might technically be toxic, but because the enforcement is so selective it can effectively become a trade barrier. U.S. compliance is voluntary which shows just how toxic it is. Ethyl carbamate is produced by exotic copper reactions and is reduced by using stills that are combinations of copper and stainless to reduce the reactions. Substrate is also a factor and I’m under the impression that the Scots bread new generations of malt to reduce ethyl carbamate. Even post bottling it can form from UV reactions and it increases in fruit eau-de-vies that have sat on a store shelf.

The raw material sugar cane

The production of traditional rums combines the production of ethanol with the production of ethanol aromatic or non alcoholic compounds, during the fermentation. This production depends on the suitability of the must, and therefore of the raw material, to meet the needs of the yeast and the co-fermentation agents are the bacteria. We are interested in sugar cane as a plant resource, (Célestine-Myrtil-Marlin and Ouensanga, 1988), its contents, and that of molasses (Célestine-Myrtil-Marlin and Parfait, 1988) into organic acids. Measures have also been of the age of sugar cane (Célestine-Myrtil-Marlin, 1990). The organic acids act on the metabolic behavior of yeast, during fermentation (Fahrasmane et al., 1985).

Work has begun on methods of processing sugarcane associated with a method of sugars (Célestine-Myrtil-Marlin and Parfait, 1987). We needed precise and reliable methods for measuring sugars and monitoring their evolution during bio transformations (Célestine-Myrtil-Marlin, 1991).

Their involvement has deepened so much that they’ve worked backwards into investigating and developing more suitable substrates. Arroyo never got that far.

Treatment and recovery of effluents

The distillation of fermented rum media produces discharges, waste water, vinasse, which contains a polluting charge. Programs in our Unit have contributed to the characterization of the vinasses and propose processes of depollution and valorisation, by digestion to form methane.

The pollution flows generated by the distillation of cane molasses alcohol are particularly high: 950 to 1900 kg DCO / m³ of pure alcohol (A.P.) produced, i.e. a polluting load of 13 to 26,000 equivalent per day / m³ A.P. product. The distillation of agricultural rum represents pollution is six times lower: 250 kg / COD / m³ A.P., i.e. 3000 equivalent inhabitants day / m³ A.P. product (Bories et al., 1994). Where the organic load of waste water from the agro-food industries, such as distillery, is discharged without precaution into the natural environment, it causes different forms of disadvantages, the most characteristic being water pollution and odor pollution accompanied by the nuisances they induce.

Various channels have been proposed for the elimination or treatment of vinasses: evaporation incineration, irrigation, anaerobic lagooning, microbial biomass production, digestion anaerobic digestion or methane digestion. The latter is a natural biological process consuming and reducing organic pollution. Its application in sewage treatment plants, effluents and at the same time the production of combustible biogas.

In Guadeloupe, in a major distillery, the molasses vinasse is digested anaerobic, according to a process sized by an INRA study. This process makes it possible to under normal operating conditions:
• decontamination with 60% of DCO eliminated,
• energy production: biogas representing 60% of the energy needs of the distillery (Bories et al., 1988).

Pilot trials result in more than 95% removal of DCO from juice
of cane by anaerobic digestion (Bories et al., 1994). The biogas produced is of very limited interest for the agricultural distillery, as it has bagasse as fuel.

Arroyo never really got into effluence disposal but it was the main subject of the rum pilot plant. What is interesting is that its less useful for agricole distilleries because they already have tons of bagasse to use for fuel. Distilleries have gone to more extensive efforts to be green than you’d think without consumers even noticing.

Conclusion

Two symposia on the traditional rums of the French Overseas Departments were held, in 1994 and 1996 respectively in Guadeloupe and Réunion. They were an opportunity for meetings between professionals, technical institutes, administrations, institutes of research. These events resulted in the publication of Acts which provided an update on the problems and questions of the production of traditional rums.

I was not aware of these. Will have to track down any special papers.

The work carried out on the manufacture of traditional rums, over the last thirty years, knowledge and understanding of bacterial flora and its products, the mechanisms of quality in these products, and to suggest ways of remedying them. The products of bad qualities are now much less frequent than thirty years ago. The medals won by the distillers of the French West Indies, to the agricultural competitions are more and more numerous.

When it is noted that problems are less frequent, it makes me wonder if we are seeing flaws marketed as features coming back to the market such as with natural wines. New producers (and bottlers) are coming online that are wading into this ambitious grand arôme territory and are not technically versed enough to see what should be regrets and missed opportunities. We do not understand enough of beauty and sauvity or what is possible to make all the connections. I’ve tasted a number of acrid spirits that are raising flags in my mind (not from the French!).

Work on yeast strains collected in rum distilleries has made it possible to select a strain which constitutes a tool to contribute to the conduct of the fermentation. There are fewer knowledge on the functioning and bacterial dynamics of distillery ecosystems, marked by a great biodiversity. There is phylogenetic proximity between the lactic bacteria of fermentations and corynebacteria, some of which are sugar cane pathogens.

I don’t completely understand the bacteria being described here and I think it might just be microbiologists nerding out and pushing the boundaries of what can be investigated.

On the raw material, there is the need to define a technical itinerary of agricultural production and post-harvest treatment, suitable for processing by rum, taking into consideration other organic acids, aroma precursors, markers, tracers, etc. cane juice, sterile, stabilized by tangential microfiltration, which we have developed, we have a study environment of behavior, in pure culture, of microbial agents.

Things get really interesting here and I just know rules of thumb for dealing with fresh cane and haven’t actually read anything too aroma centric. Cane degrades rapidly and the recoverable sugars changes, but if your objective isn’t sucrose recovery, what can be said specifically about aroma? Filtration or centrifuging becomes significant here, either for logistics of large productions or for optimizing aromas. “Undefecated” fresh sugar cane juice rums are very different as noted by Arroyo, but I’ve never read exactly from a microbiologist.

Most of the work was carried out on a laboratory scale. Consideration of the matter and co-cultures requires the addition of a pilot-scale device to the laboratory scale, and also to carry out operations on industrial sites.

We have not developed any distillation activities. This manufacturing step is also significant to the development of product quality.

The maturation of rums is a stage on which we have for the moment only done preliminary exploration, through the use of woodlands and red woods of Guyana.

Very exciting! Tropical cooperage!

The singular aromatic character of traditional rums has received little attention. It has the advantage to be outside the field of alcoholism. There is potential for innovation to formulate products of the rum distillery, responding in a targeted way to these aromatic uses.

Treatment and recovery of effluents benefit from the results obtained, both on effluents from molasses than on sugar cane juice effluents. On the former, there are treatments of upstream or secondary of different types to be studied or to be dimensioned: plowing, spreading, lagooning …

The traditional rum model is relatively complex, because it involves:
• treatment of raw materials: molasses and cane juice (biochemistry, physiology …),
• complex bioconversions: alcoholic fermentation, bacterial co fermentation, methane fermentation of downstream effluents,
• unit operations in process engineering: grinding, extraction, distillation ….
• maturation treatments of distillates, varying in length, to develop various qualities of products.

The different tools and itineraries mastered and the achievements of the research and development in the sector cane-sugar-rum can find applications in the agro-processing of tropical plant resources.

In summary, the work will benefit many, even beyond rum!

Bibliography

Bories A., Raynal J., Bazile F., 1988. Anaerobic digestion of high-strength distillery wastewater (cane molasses stillage) in a fixed-film reactor. Biological Wastes 23, 251-267.

Bories A. Bazile F. Lartigue P., 1994. Traitement anaérobie des vinasses de distillerie en digesteurs à micro-organismes fixés. Actes, Colloque sur les rhums traditionnels 219-242. ISBN N° 2-9506 860-2-8.

Bourgeois P., Fahrasmane L., 1988. Effet de stéroïdes de la canne à sucre sur des levures en fermentation alcoolique. Canadian Institute of Food Science and Technology 21, 5, 555–557.

Célestine-Myrtil-Marlin D., Parfait A., 1987. HPLC analysis of sugars in sugarcane stalks. International Sugar Journal 89, 186–190, 217–220.

Célestine-Myrtil-Marlin D.A., Ouensanga A., 1988. Distribution of simple sugars and structure polysaccharides in sugarcane stalks. Sugar Journal January, 11-14.

Célestine-Myrtil-Marlin D. Parfait A., 1988. HPLC determination of organic acids in sugarcane and its industrial by-products International Sugar Journal 90, 28–32.

Célestine-Myrtil-Marlin D., 1990. Influence of cane age on sugars and organic acids distribution in sugarcane stalks. Sugar y Azucar, 85, 17-24.

Célestine-Myrtil-Marlin D., 1991. Valorisation de la chromatographie liquide à haute performance (HPLC) à l’intérieur de la filière canne à sucre : de la sélection variétale au contrôle de la fabrication en usine. Industries alimentaires et Agricoles 108, 621-623.

Dubois P., Parfait A., Dekimpe J., 1973. Présence de dérivés de l’acroléine dans un rhum à goût anormal. Annales de Technologie Agricoles 22, 2, 131–135. [my translation]

Fahrasmane L., Parfait A., Jouret C., Galzy P., 1983. Etude de l’acidité volatile des rhums des Antilles françaises. Industries alimentaires et Agricoles. 100, 297–301. [my translation]

Fahrasmane L., Parfait A., Jouret C., Galzy, P., 1985. Production of higher alcohols and short chain fatty acids by different yeast used in rum fermentations. Journal of Food Science 50, 1427-1436. [already in English but it may be missing the very last page]

Fahrasmane L., Parfait A., Galzy P., 1986. Propriétés fermentaires des levures de fermentation. Industries alimentaires et Agricoles 103, 125-127. [my translation]

Fahrasmane L., Ganou-Parfait B., Parfait A., 1988. Yeast flora of Haitian distilleries. MIRCEN Journal 4, 239–241. [already in English]

Fahrasmane L., Ganou-Parfait B., Bazile F., 1989. Le métabolisme du soufre dans la rhumerie. Mircen Journal 5, 239-245.

Fahrasmane L., 1991. Amélioration du rendement du rendement de la fermentation alcoolique de milieu à base de canne à sucre. AFCAS : 1re Rencontre internationale en langue française sur la canne à sucre. p. 310–311.

Fahrasmane L., Ganou-Parfait B., 1998. Microbial flora of fermentation media. Journal of Applied Microbiology 84, 921–926. [already in English]

Ganou-Parfait B., Parfait A., 1980. Problèmes posés par l’utilisation de Schizosaccharomyces pombe dans la fabrication des rhums. Industries alimentaires et Agricoles 97, 575-580. [my translation]

Ganou-Parfait B., Fahrasmane L., Parfait A., 1987. Bacillus spp in sugar cane fermentation media. Belgian Journal of Food Chemistry and Biotechnology 42, 192–194.
[already in English]

Ganou-Parfait B., Fahrasmane L., Célestine-Myrtil D., Parfait A., Galzy P., 1988. Les Micrococcus en technologie rhumière aux Antilles françaises. Microbiologie – Aliments – Nutrition 6, 273–277.

Ganou-Parfait B., Fahrasmane L., Galzy P Parfait A., 1989. Les bactéries aérobies des milieux fermentaires à base de jus de canne à sucre. Industries alimentaires et Agricoles 106, 763–765.

Ganou-Parfait B., Fahrasmane L., Parfait A., Galzy P., 1991. Les bactéries en technologie rhumière aux Antilles françaises. AFCAS : 1re Rencontre internationale en langue française sur la canne à sucre. p. 303–309.

L. Fahrasmane et B. Parfait 164 Innovations Agronomiques 16 (2011), 153-164 [This is basically another version of this 30 year bibliography.] (Parent Journal link)

Ganou-Parfait B., Valadon M., Parfait A., 1991. Contribution à la bactériologie des eaux de fabrication de distilleries de la Guadeloupe. AFCAS : 1re Rencontre internationale en langue française sur la canne à sucre, 296–302.
[my translation]

INRA., 1975. Symposium International sur le rhum et alcools dérivés de la canne à sucre. Annales de Technologie Agricole 24, 239-495.
[Many of these are collected in this blog post, but I finally got the entirety of it all. There weren’t really any new papers, but there is a much better scanning of the Japanese paper. Feel free to contact me if you need anything inside.]

Jouret C., Pace E., Parfait A. 1990a. L’acide formique composant de l’acidité volatile des rhums. Industries alimentaires et Agricoles 107, 1239 – 1241. [my translation]

Jouret C., Pace E., Parfait A., 1990b. Différenciation analytique des rhums agricoles et industriels par les alkylpyrazines. Annales des Falsifications des Experts Chimistes. 87, 926, 85 – 90.

Lencrerot P., Parfait A., Jouret C., 1984. Rôle des corynebacteries dans la production d’acroléine (2-propenal) dans les rhums. Industries alimentaires et Agricoles 101, 579–585. [my translation]

Leppanen D., Denslow J., Ronkainen P., 1979. A gas chromatographic method for the accurate determination of low concentration of volatile sulphur compounds in alcoholic beverages. Journal of the Institute of Brewing 85, 350–353.

Miniac (de) M., 1988. Conduite des ateliers de fermentation alcoolique de produits sucriers (mélasses et égouts). Industries alimentaires et Agricoles 105, 675-688. [my translation]

Parfait A., Namory M., Dubois P., 1972. Les esters éthyliques des acides gras supérieurs des rhums. Annales de Technologie Agricoles 21, 2, 199–210. [my translation]

Parfait A., Sabin G., 1975. Les fermentations traditionnelles de mélasse et de jus de canne aux Antilles françaises. Industries alimentaires et Agricoles 92, 27–34. [my translation]

Parfait A., Jouret C., 1980. Le glycérol dans la fermentation alcoolique des mélasses et des jus de canne à sucre. Industries alimentaires et Agricoles 97, 721-724. [my translation]

Vidal F., Parfait A., 1994. Introduction d’une levure à aptitude rhumière en fermentation de dérivés de la canne à sucre. BIOS Boissons 249, 21–26. [My translation]