This is among the first in a series looking at numerous fission yeasts from around the world collected by the ultra brilliant Cory Widmayer.
This birectifier analysis of an outstanding rum started with an error coupled with a minor hard to understand phenomenon. The fractions were thrown out of alignment but that doesn’t matter much because we can still gather a lot of information if we understand how what happened altered the typical process. The error started with me double checking the ABV even though I received it with a label that stated 45%. For some reason I measured 50% and went off that. The birectifier fractions work off a system that revolves around 100 ml of absolute alcohol. The math to calculate sample size looks like this:
10,000 / 45% = 222 ml sample
10,000 / 50% = 200 ml sample
Upon double checking the ABV afterwards, my cheap hydrometer still reads 50% while my antique Tagliabue revenuer’s hydrometer actually reads 42% ABV. This is making me suspicious of the cheap hydrometer (which I will abandon) and may explain a significant percentage of the problems this analysis faced. Something I thought could be throwing off the hydrometer is the unique surface tension of such a heavy rum but who knows how significant that is in practice.
The hard to understand phenomenon is how distillates that have below average fusel oil behave. They almost seem to consistently end their 4th fraction early which may be some sort of azeotropic phenomena, but I don’t have precise enough instruments to say for sure if I’m having discrepancies hitting 100 ml of absolute alcohol. It would be nice to own a u-tube densitometer.
If the distillate changes to 42%, I should have inputted 238 ml of sample. I inputted 200 ml so I was short 38 ml which is 17.1 ml of absolute alcohol and could explain the vast majority of the problem. Any fusel oil phenomena could be much diminished and typically makes you want to cut the 4th fraction short by 5 ml because tons of high value aroma start coming over. Arroyo tweaked Dr. Luckow’s system from 96 ml of absolute alcohol to 100 ml so that high value aroma would typically be pushed to only the 5th fraction and not share space across 4-5.
Something else to consider is that if this rum was short 17.1 ml of absolute alcohol, each fraction would become proportionally more concentrated. I do have enough sample to start over, but I have three more distillates to go in this series and feel we can already say enough about the promise of this yeast; quite promising!
When experimental ferments are distilled, we are typically just looking for assets and liabilities so cuts are never as precise as you may want them to be at a commercial scale. This distillate was uncut enough to be cloudy, however the fractions appear to show all assets and basically no liabilities. At a commercial scale it would likely be distilled to a higher ABV, and following ideas from both Kervegant and Arroyo, aged to completion where the ABV would slowly drop via the angel’s share to ideal bottling ABV with no water needing to be added (which risks aroma breakage). All the noble volatile acidity evident here in fractions 5 and 6 give the distillate a lower than average starting pH which can start catalyzing maturation reactions faster than lighter spirit. Flabbier spirits (like bourbon) often have to wait to absorb acids from the barrel to lower pH and Arroyo estimated building acidity into the distillate could naturally accelerate maturation by 6 months as a quick rule of thumb. Maturation in barrel would also increase the ethyl acetate which is very low here relative to a Jamaica rum where much is built in at the start due to fermenting in the presence of vinegar.
fraction 1: Presence of ethyl acetate, but not too significant. no other unique congener presence.
fraction 2: Slight presence of ethyl acetate but fairly neutral.
fraction 3: Very neutral inline with the typical fraction 3.
fraction 4: Visually cloudy and definite beautiful estery character. All this aroma is typically in fraction 5. Definite radiance but this is no rum oil bomb. Very powerful and persistent. Very unique character on the palate relative to other fraction 5 experiences. Not the typical acridness but almost like a biting chalkiness. There is so much concentration here it is no surprise. Possibly that biting characteristic is the fusel oil from the typical fraction 4 mingled with substantial esters?
fraction 5: More radiant rum oil character relative to fraction 6. Detectable gustatory acidity.
fraction 6: More detectable gustatory acidity, but sort of slight. Heavier rum oil like character but possibly faint non acetic free VA.
fraction 7: No significant gustatory acidity. Not too aromatic. No liabilities.
stillage: Visually cloudy. Has an exhausted character, but no off aroma. No significant gustatory acidity.