Luckow C. Über die Begutachtung von Rum, Arrak und Kirschwasser mit Hilfe der Ausgiebigkeitsprobe, Brennerei-Ztg. 50 (1933), 86-87.
[that is from a citation I have, but it is not that above citation! and is actually from two years prior! wtf?! what does this mean!? I think there were multiple version of this same paper. I can’t translate them all because of the extreme tediousness.]
[This paper was a colossal bitch to translate. My rendering is not the best so read between the words and you soak up the two or three major tests that emerge. The first is the eight fraction Micko test. The second is the exhaustive test (and I have a better framework for it coming soon) and the third is the evaporation test. These tests are all affordable and very pragmatic. Here, they were used for fraud detection, but later they were all championed by Arroyo for progressively improving spirits and building productions from scratch. Arroyo got the birectifier from Luckow. He likely read this very paper.
Will new distillers do the legwork and adopt these tests? Will someone precocious come along, use them all, and create something virtuosic?]
For the Qualitative Assessment of Noble Brandy, in Particular Rum, Arrak and Kirschwasser
H. Wüstenfeld and C. Luckow
Mitteilung aus der Abteilung fur Trinkbranntwein- und Likorfabrikation
(A.T.L.) am Institut ftir Girungsgewerbe in Berlin.
The proposals by Micko to use fractional distillation to evaluate rum date from 1911. Thus, they formed a novel way of assessing, by then largely confined to, purely analytical-chemical levels of content Alcohol, acid, ester and fusel oil to determine and incidentally submit the originals to a organoleptic test.
For us, who have always been in close touch with the practice, it was an obvious idea to judge the products of the beverage industry, which are primarily consumables, first and foremost according to their enjoyment, without, in the first place, the results of the chemical analysis to put in the background. Our department for drinking spirits has therefore long since begun to refine and expand the degustative testing methods.
Since the simple distillation apparatus proved to be insufficient for fractional distillation, the birectifier was introduced, which allows a very excellent separation and grading of flavoring substances at different boiling points in the fractions introduced and is therefore recommended again for general application at this point (cf. Fig. 1).
The distillate is distributed under extensive dephlegmation [reflux] into eight fractions of 25 ccm each, which, after appropriate dilution to drinking strength, are tasted together with the original sample and the residue resulting from the distillation. In the degustative examination, several experts are always present , The new tulip shape of the food glass (Fig. 2) has proven to be quite expedient.
All products of the wine distillery (wine distillates, brandy as well as brandy blends) are tested for the beer specified type for years by us on their quality. Again and again we have been able to convince ourselves of the usefulness of the method, and for this reason we refer in particular to the publications published here (1 [this is a long citation please refer to PDF]).
Since the odor and flavor testing of the fractions obtained on the birectifier only allows a general assessment of the goodness of the product, but usually can give no reliable indication of the intensity of the aroma, we have in the course of further work to the strength of the taste of individual for determine the assessment of particularly important congener groups. For this purpose, a method of successive dilution has been elaborated for the products of the distillery, which, to a certain extent, is to be regarded as a quantitative procedure, and is expressed in definite figures, chiefly for internal use.
The objection that the test of exhaustiveness is superfluous in so far as the level of the analysis values already provides sufficient indications for the recognition of an avinating [Avinating, also Vinieren, means the rinsing out of a wine vessel with a little wine before use.] with industrial fuel is adequately counteracted by the already often emphasized possibility of forgery by addition of missing substances up to “analysis stability”. Moreover, we are of the opinion that no proposal should be left unturned in order to gain ever more reliable evidence for the detection of counterfeiting, until someday it will be possible to arrive at perfect conclusions by far-reaching differentiation of purely chemical working methods. We welcome the proposals of various expert chemical specialists, especially those of Zellner, to standardize and standardize not only the analytical but also the degustative testing procedures in order to finally create a basis for the even evaluation of the spirits. We hope that we have also contributed to this project in order to achieve the desired goals.
The exhaustive test was later extended to other noble spirits such as rum, Arrak and Kirschwasser, lately even on raspberry juice (Diese Zeitschrift 1931, 61, 341.), where it proved to be expedient, not based on the individual fractions of Birectifiers, but from the original.
In the following, this expansion of the taste analysis of fine spirits will be discussed in more detail. Generally speaking, the method is carried out by gradually diluting the starting material with water up to the lowest threshold of taste and tasting the individual stages, starting with the highest dilution. The degree of exhaustion is considered to be the dilution of the sample in which the aroma of the starting material is noticeable for the first time clearly in the smell and taste. We understand by the dilution the dilution of 1 cc original. It is valuable for anyone who wants to get involved in the method, any standard solution, e.g. to keep a rum in stock for the purpose of controlling the particular fineness of the taste sensation, and to carry out comparative dilutions with it in cases of doubt, in order to thereby take part of the process of the subjective character of the procedure. [Arroyo used this procedure of grading spirits persistence by how far you can dilute them.]
To avoid misunderstandings, it should be emphasized that the yield test, as the name implies, should merely express the aroma strengths. The method therefore does not claim to characterize the quality of a product per se, which, on the basis of the assessment of the original in conjunction with the fractional distillation, finds a satisfactory assessment. However, in many cases it is possible to recognize counterfeits by blending with industrial spirit, which, because of its lack of flavor, has no “exhaustiveness”, as such, and e.g. for rum and arrack, it expresses the verifiability that is important for practice.
In our investigations, our main concern was to further develop the dilution methods for rum and arrack and to relate them to the quality assessment as well as in particular to the now generally conducted evaluation of the ester number. It would have been difficult, even with the extensive material (Tables 1-3), to carry out complete chemical analyzes in the hitherto customary manner, including fractional distillation on the birectifier. We put special emphasis on the evaluation of the taste quality, as it naturally plays a decisive role in trade. As a result, we have included all the resulting judgments in our compilation.
We carried out the suitability test by using 0.1 cc of original rum. -arrak, etc. diluted to 50 cc with tap water of room temperature, again brought 0.25, 0.5, 1.0, 2.0 and 2.5 cc of this dilution with water to 50 cc, so that the original product was now diluted 1: 10000 to 1: 100000. The taste test was – as already said – done in such a way that you went with the strongest thinning up to the “taste threshold”, in which the rum, Arrak, etc. was clearly expressed in the smell and taste.
It should not be forgotten here that one advantage of this simple procedure is that it can be applied to small free samples given to the buyer when making offers, and even leaves enough material for a direct tasting. – For the products of Rum production the exhaustive test is particularly suitable because the pronounced aroma of this noble brandy is still very clearly perceived even at higher dilution. In addition one sets also in Germany straight on the exhaustive quality etc. Cuttability is the greatest value, and qualities such as e.g. the “Consumption-Rhums”, which are particularly popular in England, are barely commercially available. While in the wine distillates a dilution of 1: 400 usually already represents the highest yield limit, with rum ratios of 1: 50,000, even 1: 100,000 are not uncommon.
As can be seen in Table 1, we have not given the various levels of output separately for each rum, as we have repeatedly felt that these numbers have led to misleading perceptions and quality assessments on the part of the practice. We therefore used certain numbers related to the yield values in the following way:
If in practice a Rumverschnitt is produced from an original Rum with the help of pure Spirit, one must use the alone for the purpose of the purely analytic exhaustive test according to above regulation determined dilution numbers in such a way that one simply, for example, 1 liter original volume for the production of 25000 liters of waste is considered sufficient, since the analysis indicated dilution grade 1:25000. There are considerable differences between the yield in water and that in alcohol. In fact, one and the same original rum showed a yield of 1:100000 in our dilution with water, and 1:1650 with 40% alcohol. The dilution reached in the first case a sixty times as high value. To explain this interesting observation, dilutions of vanillin solutions with both water and 40% ethanol were made in our laboratory. The vanillin proved to be particularly suitable for our experiments, as it once has a strong aroma and then in the water as in the 40% spirit in the candidate. Dilutions completely soluble and not dissociated. Here, then, the question could be clarified whether certain solubility or dissociation ratios play a role or whether the cause may be due to the anesthetic effect of the alcohol over the taste nerves. The same enormous differences also occurred with vanillin. When diluting with 40% spirit in the ratio 1:250,000 the vanillin aroma was barely noticeable, while it was just expressed in the dilution with water in the ratio 1:4000000 (1 g dissolved in 4000 liters). As we know, very similar observations have been made on essential oils and drugs. It seems therefore to be a general phenomenon which, in our opinion, must be traced back to the particular physiological effect of alcohol. [should you do the exhaustive test with only water or an neutral ethanol blend?]
Of course, with simple numbers you can not combine a special term in and of itself. Consequently, we have coined a certain expression for each value. The dilution which was most prevalent in the testing of our extensive material, we called “4-out-of-25000”, we called “extensive normal type”, the better grades 5 and 6 = 1: 50000 etc. 1:100000 received the rating “very” etc. “very extensive”. Products exceeding this limit were given the name “very particularly extensive”. Below the normal type, for the dilution numbers 3, 2 and 1 (1: 16700, 1: 12500, and 1: 10000, respectively), we chose the terms “moderately extensive”, “less extensive” and “hardly extensive”. We believe that in this way we have correctly characterized the abundance of the various types of rum, but we would like to emphasize at this point that we consider this evaluation procedure primarily for us, ie. for our internal use, however, we recommend that all interested parties in the assessment of rum should also make use of it.
In Table 1, the results of the rum studies are published. The alcohol content of samples from Jamaica ranged from 71 to 81% by volume, usually from 76 to 78% by volume. The products are ordered according to the amount of ester number. Here you will find surprisingly high values, up to over 3000, but also very low, to less than 100. On the lowest limit are the non-Jamaica products, although it must not be overlooked that rum samples from Jamaica sometimes have very low ester numbers. The majority of the products have ester numbers between 200 and 800. For the sake of completeness, it is added here that the ester number means the amount of ethyl acetate in grams contained in 100 liters of pure alcohol. Thus, if, for example, an original 810 g of ethyl acetate is found in 100 liters of original rum, the ester number of the product in question is 1072 calculated on the basis of the equally determined alcoholic strength of 75.56% by volume.
Generally, though not always, high yield values correspond to high ester numbers. However, there are isolated high-grade rums, which do not have a particularly high yield, as well as the number of ample rums with relatively low ester values is by no means as low as one might expect. This observation seems understandable, considering that high ester numbers indeed by certain esters, e.g. as ordinary ethyl esters, can be conditional. Of course, such compounds do not contribute much as a result of their less pervasive aroma to increase the yield. [does ethyl acetate skew the ester number? (yes)]
If one compares the quality assessment with the Ester numbers, then in the compilation noble and fine types are found with only moderate Ester numbers and no too much from the exhaustive test. These inventories are less suitable for blending purposes than for direct uncut sales in their original state. Looking at the table, it will be noticed that the highest ester grades were generally not considered the finest grades. This perception can be explained by the fact that the somewhat obtrusive, often burning, taste of the ester covers up any finer aroma that may exist. Here, the well-known rum sample [grogprobe], which is often used in practice, for the evaluation of the quality of decisive importance as the simple Kost tasting in the original. We always prepare 1, 2 and 5% rum when warming up this sample by dilution. From a good Jamaican rum is to be demanded that it still clearly shows its typical flavor in 1% dilution. —Especially jaunty [juchtige] products that did not appeal to our taste, but of course in many cases of value. we could not always call the best. Often, however, just these products will be very sought after in the trade and, accordingly, be paid high.
There is much less to say about the Arrakoroben [not sure of that suffix besides golden?] than about the rum products. In addition, much of the above is also true here. There is a certain poverty of this brandy [lack of?]. Again and again we find the same names for Batavia-Arrak: A.P., O.G.L. and K.W.T. The results of our investigations are summarized in Table 2.
Table 2. Arrak analyzes, ordered by the ester number.
[bezeichnung der firma = name of the company
verdunnungszahl = an index of persistence
ziemlich ausgiebig = quite extensively
Mäßig ausgiebig = moderately extensive
these are scaler adjectives. recht also translates to “quite” but I think its in the middle of the scale.]
Due to material shortages, it was only possible for 11 products to carry out the analysis for alcohol and ester number. The values obtained here are consistently within a certain, narrow range. The ester numbers are significantly lower than rum and vary between 230 and 470 g in 100 liters of pure alcohol. Consistent with this, the dilution values obtained in the same way as rum are not particularly high; usually they were in our experiments at 1:16700. For this reason, as we can see from the Arrak table, we have chosen some other designation of sufficiency, which takes into account the generally lower cutting ability. Variety poverty is also expressed in the taste [they are not well differentiated]. Despite certain differences in quality, certain pronounced differences in taste could not be detected in the individual samples. Although the rums are very closely related in flavor, the arrak varieties generally lack the estery bouquet that is often so pronounced in rum, the slightly fragrant flower; on the other hand, the jubilant character, perhaps because of the shortage of esters, was all the more evident. We should not fail to point out that in the degustative testing of the arrack samples, the aroma of the molasses was sometimes reminiscent of a slightly acidic “herbaceous” smell and taste, which is particularly characteristic of all varieties.
Besides rum and arrack, we also tried to improve the method of evaluation for kirsch. Just as we had done with the other two fine brandies, so we were here also guaranteed by flawless companies to get sent pure products in order to carry out the necessary investigations with them.
Table 3 summarizes the results of the 35 analyzes which were again ordered according to the ester content. In the present case, we carried out complete chemical-analytical tests and also determined the sufficiency of all products. The purely analytical evaluation extended in the usual way to the determination of the content of alcohol, acid, ester and fusel oil. The otherwise often customary hydrocyanic acid determinations were not listed because, in our opinion, they do not say much for the assessment of authenticity; The hydrocyanic acid originates from the known glycosidic fission process, to which bitter almond oil also owes its origin. Depending on the method of milling and the mashing method, as well as the age of the mash, this process can proceed in various ways, but not sufficiently clarified in its details, until the time of burning off.
Again it should be noted that fractional distillations were not carried out in the cherries; On the one hand, on the one hand, we had to renounce the greatness of the analyzes, for which there was usually only limited material available, and on the other hand we had made it our task here as well as in the Rum and Arrak investigations, first and foremost once to establish the relationships between the analytical values and the tasting as well as the yield test and the evaporation test. However, in order to complete the quality inspection, fractional distillation is in any case valuable and necessary as part of a complete commercial analysis.
In particular, it should be noted at the values given in Table 3 that the acidity figures vary within rather wide limits, they increase up to 308 mg in 100 cc of pure alcohol, with the exception of kirschwasser no. 23, and go down to 12 mg. In the main they move between 60 and 190 mg with an average of 123 mg. The fluctuating acidity levels are explainable, because they are due to the very different – depending on chance – treatment of the mash and its age as well as the course of the fermentation and distilling process. It is likely to be acetic acid only, the formation of which is caused by bacterial secondary processes (vinegar) in greater quantities and is influenced by the more or less airtight completion of fermentation barrels and the storage time of the mash, the temperature and other factors. The same applies, to a certain extent, to the formation of esters, which is also in some connection with the type of mashing and with bacterial secondary fermentation, which is known to take on a considerable scale during prolonged storage, quite apart from the different carried out separation of the lead. The ester levels are between 684 mg as the highest and 56 mg as the lowest value and average 298 mg. The highest amounts of ester are probably due to vinegar pricking, associated with prolonged storage, the lowest by pure terminated in a short time yeast fermentation, perhaps also by extensive separation of the foreshots. It is important to establish statistically that a number of high-quality products are also in the last part of the table, which has the lowest ester levels.
The values for the higher alcohols also showed considerable fluctuations (651-5724 mg fusel oil per liter of pure alkobol, on average 2769 mg). High-quality products with well-defined, characteristically strong cherry flavor almost always have high fusel oil figures (except Kirschwässer No. 11 and No. 14). There seems to be a certain correlation between the ester values and the fusel oil figures inasmuch as in the last part of the table, which contains the low ester numbers, there are also no excessively high fusel oil figures. The formation of fusel oil in the mashing process has not yet been scientifically clarified in order to be able to draw further speculative conclusions from the table. The higher alcohols are usually completely pass into the distillate, especially since the distilling process is carried out on simple, smaller alembics without further dephlegmation.
In the degustative examination of the Kirschwässer we noted in all cases a more or less strong, floral-like aroma of the typical cherry bouquet substances, of course, with certain, by origin and location (influence of cherry variety, the climate and the soil) conditioned taste nuances. Pure bitter almond (kernel) taste has rarely been observed to a greater extent; usually he stepped back very much and was not noticed at all. The same must not be confused with the cherry flavor. Since experience shows safest a forgery, especially with fruit brandy of other kinds (plum brandy and the like.), Best in the aftertaste can recognize, was placed on this particular value. In the majority of the samples, we found a more or less pronounced trailing character, which is characteristic of the noble brandy produced on simple alembic apparatuses of various origins, in particular of wine distillates, rum and arrack – not to be confused with the well-known burning taste of fusel oil. The nuance seen here is usually reminiscent of free fatty acids and is probably due to a somewhat late switch to tails, but on the other hand gives the products a certain typical character. However, it should not be concealed that this aroma was missing some cherry wines, which in and of themselves qualitatively made a particularly pure impression.
On the Kirschwässer we also applied the exhaustive test in such a way that we used 5 cc of the original product first filled with water to 100 cc and then again each 0.1, 0.5, 1.0, 1.5 and 2.0 cc supplemented with water to 100 cc, again here we determined the lowest limit by an in-depth smell and taste test, in which the aroma was just clearly expressed. We estimated that, if the lower dilution was too weak, the subsequent dilution too strong, the mean values between the individual dilutions, and so, calculating the individual yield values, we arrived at the following dilution series:
[Verdünnung = dilution
We round off the values of 1:6667, 1:2667, 1:1333, and 1:1142 to the corresponding hundreds, so as not to mislead you about the degree of accuracy of the yield test. It was found that of the 35 samples examined 10 showed the particularly high yield of 1:4000. For the majority of products, yield values ranged from 2,000 to 2,600. Only three samples gave rise to concerns about the lower than 2000 number of outlays. Here, too, it should not go unmentioned that in an exceptional case (no. 33) a good-tasting Kirschwasser with a high degree of yielding had only very low ester and fusel oil values. In general, high exhaustive test numbers correlateded with higher than normal levels of higher alcohols as well as higher other analytical numbers, e.g. esters.
Finally, we have to report on a method of examination, which we also always apply when assessing kirschwasser. This is the so-called evaporation test. It is common practice to prove the authenticity, in particular the test for a possible addition of plum eau-de-vie by allowing the Kirschwasser residue in a tasting glass to evaporate, and then the next day odor detect the remaining flavoring. We designed this method in such a way that we empty the glasses at the end of the tasting and then leave them covered overnight with a watch glass. The alcohol as well as the more volatile kirsch bouquets evaporate, while the watery constituents as well as certain volatile fumes remain and are expressed in a certain mixed odor. It emerged in our experiments that the bitter almond aroma could never be detected. Also, the actual Kirschwasser bouquet was lost mostly, while in other cases, especially in high-quality products, still a clear bouquet was expressed. Naturally, the trailing character already mentioned in the tasting was very noticeable here, often particularly striking. This can be clearly seen in the smell test of plum eau-de-vie by a plum-like aroma, while in pure Kirsch water reminds one only on cherries, but also does not come to light at all. We agree with the view often held that the connoisseur should in any case consult the evaporation test. It can also be observed here that certain strange nuances, such as e.g. barrel smell, impure fermentation, foreign flavorings and the like, are clearer than in the original to recognize. In cases where the evaporation sample appears perfectly pure and neutral in the odor, one can almost certainly conclude that it is pure, not mixed with other fruit brandy.