My recent deconstruction of a role model rye whiskey led to discovering a terpene emulsion which raised a lot of questions. The big one is whether the terpenes are freely in the rye and easy to express themselves or if they have to be unlocked by fermentation with a lot of effort such as in rum. The plan to find out was to distill unfermented rye grains with ethanol using the birectifier and see what happened. This may lead to a very simply way to assess grains, or so I thought.
Previously, in my distiller’s workbook exercise 9, I had a lot of fun distilling unfermented grains over top of a white dog to get a sense of their character. The plan was to do something similar but on a smaller scale with the birectifier. The rudimentary protocol was combining 250 ml of 40% abv neutral spirit (to have 100ml of absolute alcohol) with 50 grams of grains and an additional 50 ml of water. Defoamer was also absolutely necessary and the operation could not be performed without it (It is extremely useful to learn about phenomenons like puking on glass, where everything is visible, to prevent very costly errors on the large scale).
Fractioning malted rye with the birectifier produced an incredible spicy RYE! first fraction, but nothing else notable and no terpene emulsion. The simple protocol also produced some scorching on the bottom of the boiler, but no scorched taste was evident.
What this means is that the terpene emulsion is back to being a divine phenomenon, present in the greatest spirit role models, and we have much to learn about unlocking it.
I have three more types of rye grains to try and I’m going to change the protocol. It may be practical to add enough ethanol to swell the grains and have enough free to draw off 250 ml (containing 100 ml of absolute alcohol). This would be cooked sous-vide (i.e. 100% reflux) for a time period and then separated so the liquid that goes into the birectifier distilling flask has no significant solids to scorch.
There may still be a lot of value to evaluating grains in this way, but we need to determine where what we want is (in terms of volatility). It may be immensely valuable to brewers to know what grains produce the best top notes (many already know, but this may add weight). If any extraordinary and differentiated character is only in the first few fractions, it will not make any sense to collect anything beyond that and typical 8 fraction collection can be cut short.
An interesting phenomenon that popped up during fractioning after the alcohol was exhausted is a unique condensation. This is likely due to long carbon chain aroma precursors that are not aromatic in their present state, but splittable during saccharification and then fermentation. We can’t exactly use the birectifier to quantify them, but we can as students put a face to the name. Saccharification may actually be a point in production we should look for the freeing of terpenes.
The next major protocol to sort out is the assessment of a fermentation with the birectifier pre-distillation on a big rig. This is a holy grail idea. If you know what lurks in your ferment, you can begin to progressively improve it and then understand how to optimally distill it. When we really get good at this, and have controlled model ferments to work with, we can start to outline yeast properties. When we also get really good, we can start to grade spirits A, B, C, or D and run different distilling routines. Automation may make this far more viable.
The birectifier is mainly used to analyze spirits from the rear so that we have actionable information to influence the next batch. That is valuable enough. The goal is to also work from the front before even hitting the big alembic, but a lot of basic science has yet to be conducted.
The big first decision to work out is to perform a stripping run or not. The Germans used a stripping run. The stripping run can likely best be performed by the birectifier as opposed to a different distilling head with automation programmed to collect only one fraction. It can then be run again with a charge scaled to 100 ml of absolute alcohol and run more slowly to collect the 8 traditional fractions. This may add an hour to the process and an amount of extra active time, but these are the facts of life when you are trying to do something incredible. It takes an very significant amount of reflux to get the fractions to adequately align.
An alternative stripping still would be something like the Amphora Society PDA-1 which can be used on very small boilers. I’ve actually used it mounted atop glass boilers and the Distiller’s Workbook was actually written for the PDA-1.
Degassing and defoamer are crucially important for distilling small scale ferments. A ferment can be degassed adequately with a magnetic stirrer or in an ultra sonic bath. For defoamer, I used Atmos 300k. Copper may be necessary and down the road we’ll have to test adding it or not.
The first ferment I chose to explore building a protocol was a barrel aged sour from a local brewery. It was quite delicious, but highlights that brewing for beer is wildly different than brewing for distilling. The objectives are much different and we have to begin outlining how exactly if many beer breweries are going to take their success and diversify into distilling. For starters, this elaborate ferment contained no terpene fraction and was likely pricked by acetic acid.
Beers may also provide a great opportunity to learn about flaws in distillery ferments because what is a flaw for a distiller can easily be a feature for a beer brewer. Acetic acid likely contributes positively to this sour. Some beers deliberately use brettanomyces and we may be able to distill those to learn about the volatility of brett character and how to spot it. Certain taints could grade a spirit C or D forcing distillation at a higher proof and narrower cuts to avoid it.
One more phenomenon that is educational to see in glass is the stillage (aka backset or dunder). Many things that were in solution before boiling come out of solution after. These substances have the potential to scorch and, to use an Arroyo word, create tufo. This was a beer clarified enough to be drinkable (and no tufo was formed), but imagine a molasses wash distilled on the lees. Without modern day agitation (stirrers with explosion proof motors), tufo could easily taint a spirit.
One more thing to consider when working from the front of a spirit (not yet distilled) instead of the rear (distilled), nothing has yet been taken as heads to tales so we are fractioning everything, not just the hearts. This means we can expect abnormal levels of the most ordinary congeners, mainly ethyl acetate and fusel oil. Our heads cut decision starts at fraction 1, while our tails cut decision actually starts at fraction 4 and 5.
Beer 8.2%. Used a final gravity of 1.005 to scale it to 100 ml. (fractioned without a stripping run)
Fraction 1: Definite concentration to the point of non-culinary aromas. This seems like a very rich fraction 1.
Fraction 2: Hollow fruitiness characteristic of the spill over from fraction 1.
Fraction 3: Grain aromas. Nothing offensive.
Fraction 4: No evil fusel oil “wraith“. Possibly things were not distilled high enough to collect all the fusel oil in this fraction. Some aromas that imprecisely seem fresh.
Fraction 5: Nothing extraordinary. No terpene emulsion. Crystal clear. No character comparable to any other fraction 5. Definite gustatory-acidic character. Very faint grain character. The whole thing seems very chaotic. Possible fusel oil.
Fraction 6: Slightest acrid non-culinary aroma. Definite gustatory-acidic character.
Fraction 7: Slightest acrid non-culinary aroma. Definite gustatory-acidic character.
Fraction 8: Nothing prominent. The slightest vaguest sour smell. If there were flaws, prominent brettanomyces, or tufo (from scorching of proteins) we would expect them to show up in the last three fractions.
So many questions are raised. Is our protocol all right? This is an absolutely delicious beer and I’ll enthusiastically seek it out again, but is it any kind of role model? Should we be looking at things like Chimay first?, beers that have captivated imaginations of a lot of people.
There is a lot of practical work ahead.
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