The birectifier coupled with other German organoleptic techniques holds a lot of promise for developing aromatized spirits other than gin. Orange liqueurs, like the triple-secs, may be a great example. We may even gain insights through studying role models as to what defines the sub-categories like triple-sec versus curaçao.
I’ve done tons of work with orange liqueurs in the past. Joseph König’s 19th century curaçao may be a great starting point as well as the works of Joseph Merory. Unlocking the secrets of orange liqueur has been of great personal interest. I want any small distillery with a tasting room where they have to produce everything they sell to pour perfect Pegu Clubs to their hearts content. Every such distillery should own an Amphora Society PDA-1 for such small production lots.
The first thing we need to tackle before we can fractionate an orange liqueur is to determine how many fractions we are going to collect and what impact the sugar will have on the process. Will sucrose impact our typical ramped heating scheme? Based on my finding with gin, I thought it would be safe to only collect 6 fractions. This would leave enough water so that the sugar never got super heated enough to scorch.
The water from skipping two fractions was easily adequate, but it is worth considering that nearly 3/4 of an oz. gets held in the inner rectifier (the five bulbs) towards the end of distillation which reduces the water available in the boiler.
The heating scheme was not effected by the sucrose. What is interesting is that energy required to boil is more like smelting than melting. The energy required to liberate the liquid to vapor is far more significant than getting the mass to merely heat to boiling. If you added 10% more volume in the form of only water, it would not take anywhere near 10% more energy to complete the process. The bulk of the energy is only required for what escapes as vapor. Beverage distillers get to gloss past this, but operators of big column stills for beverage, petroleum, or anything else, know the ins and outs of energy intimately. For large producers efficiencies as small as a percentage point can be worth startling amounts of money, often enough for whatever idealized equipment makes it possible.
As for the output, evaluating a triple-sec straight is challenging. If you lined up three final products of intensity varying by 10% it would take a savant to differentiate them. Hypothesizing beforehand, it is hard to say how the birectifier fractions will differ. On the one hand fractions are magnified, but on the other hand defining character also get spread out across fractions making it easier to evaluate.
Merory describes the use of lots of botanicals in his orange liqueur. Will any of them be recognizable like in gin analysis? Will the birectifier unobscure their subliminal nature and teach us how to use them?
Grand “M” Type Flavor MF 257 (Continental Formula)
(a) Extract the following comminuted botanical ingredients:
4750 gm. orange peels, bitter
2500 gm. peppermint herb
2250 gm. orange peels, sweet
1750 gm. lemon peels
1500 gm. coriander seed
1500 gm. ginger
1500 gm. orange blossoms
0875 gm. cinnamon
1075 gm. cloves
0875 gm. angelica seed
0250 gm. cardamom
0100 gm. tonka beans
0110 gm. saffron
Any time we face too much intensity, we may benefit from using the Wüstenfeld’s exhaustive test where systematic dilutions are evaluated to find the point of exhaustion where aroma can no long be perceived. This would help our own product be compared to a role model when evaluating oppressively cloying aromas like orange peel.
Fraction 1: Non-culinary notes without any serious intensity. Slightest orange character. I suspect the brandy base for the liqueur holds fermentation congeners such as ethyl acetate and acetaldehyde.
Fraction 2: Growing orange character, but it doesn’t feel too full.
Fraction 3: Same level of orange character as fraction 2.
Fraction 4: Significantly more orange character and it feels fuller somehow. Hard to determine if any fusel oil lurked in this fraction.
Fraction 5: Some orange character, but it feel like less than fraction 4. There are lots of other angular auxiliary notes, but absolutely nothing is obvious. This could likely be the expression of all the extra botanicals Merory lists. They are subtle and no doubt only make a subliminal contribution to the final spirit.
Fraction 6: There is almost some slight inharmonious character in here but it seems rather laissez faire.
(Opportunity could be taken to evaluate the stillage for sugar content.)
The experience of tasting a triple-sec fractioned by the birectifier is far different than a gin. Seeing it laid out also makes me a lot more confident in actually making one. I feel like the birectifier could get you through it, or if you accidentally produced a hefty concentrate, help you blend it down appropriately. The vintage nature of the sample possibly raised some questions, but nothing about it felt too extraordinary. I strongly bet there is no obvious difference between modern day Cointreau.
Working backwards, what was remarkable is how different fraction 5 of a Cointreau was relative to fraction 5 of a gin. The auxiliary botanicals of an orange liqueur are far more minor than a gin. Would it be fair to say they have less than half the intensity?
And then that orange aroma? It is far more spread out than I would have thought. My best guess beforehand was that it may have appeared only in fraction 5. A concept I hypothesize spreads it out across the fractions is liquid entrainment. Entrainment in this context has to do with physical zones where liquid lives in the still delaying the movement of congeners in terms of ideal factors like boiling point and relative solubility. Boiling point and relative solubility can dictate a lot, but entrainment in a column (by sub optimal throughput) up is likely far more significant to congener distributions than the beverage literature ever describes. When significant quantities of the same congener are in a distillate, the randomness and non-ideal nature of liquid entrainment will spread them out. That is why in typical distillates we see ethyl acetate spread across fractions 1, 2 and 3. It is also why Arroyo’s concept of reducing ordinary congeners to justify distillation at lower proofs is so important a concept. The way that the orange aroma gets spread, means you may never experience a fraction that is cloying and forces evaluation by the exhaustive test. More experience and case studies will say if that is a correct assessment.
This all seems straight forward and like we’re out of the woods, but we still have to reconcile the idea that orange liqueurs are produced with significant ordinary terpene removal as described by Merory. Making cuts is probably very important to orange liqueur production. For starters, did a “living” spirit go in with a lot of ethyl acetate so that after a second round of cutting it was greatly reduced? I use the term living to denote a spirit with fermentation congeners (aka non-alcohol number) as opposed to a highly rectified neutral spirit. These ordinary congeners that are retained can add vitality and support other aromas in perceptual ways.
Secondly, regarding terpene removal, what should be pointed out is that ordinary terpenes louche, but the first fraction from the birectifier was crystal clear. Merory gives some cryptic advice on terpene removal from his arm chair:
(d) Procedure: The 40 gal. flavor distillate first fraction of (b) is mixed with 40 gal. water. It is allowed to stand a few hours for separation of terpenes which are removed by decantation and the aqueous solution is then filtered. The terpene-free flavor is redistilled at atmospheric pressure, slowly, and in the same manner as in procedure (b), to obtain a first fraction:
20.00 gal. flavor distillate of about 80-84 percent alcohol content. It is then used in (m).
I could not say much more at the moment besides that now with the birectifier we have a method of knowing what is normal in a final product. Camper English visited Cointreau and described their terpene removal process by continuous centrifuge.
If you would like to understand more of the sensory whys of terpene removal, years ago I posited the idea of contrast enhancement through terpene removal.
This will require more thought, more experimentation, and more case studies.