Birectifier Analysis of a Brettanomyces Rum

This project started as an interesting challenge. Cory Widmayer asked Wild Pitch Yeast for the most aromatic Brettanomyces they had. By this point, Cory and I had extensively talked about Brett which was basically just me listening and trying to read along as best I could. I have not personally experimented with it. There was quite a large accumulation of Brett related research papers in our shared drive. Cory’s theory was that he could tame the aroma typically associated with spoilage and unleash a different side of the yeast’s personality with tailored nutrition and fermentation at a constant high pH. He was also anticipating incredible fermentation efficiency.

Brett has popped up in some surprising places besides beer and wine. Researchers were finding it in fuel ethanol ferments, and upon learning more about it’s unique metabolism, it has been tried in cachaça production. This spirit from Cory somewhat reminds me of the gold cachaças my brother tries obsessively, but transposed on a molasses ferment where there is no complementary vesouté character. I had two gold cachaças on hand to compare and they seem to differ by having a rounder core of aroma with a deeper persistence than the tertiary seeming aroma from Brett, but there is still an obvious likeness. For the record, I have yet to analyze cachaça with the birectifier even though it is a staple of the house.

I approached this analysis with some trepidation. When looking for assets and liabilities, what would I find and where? Would the very first and last fractions be very different from the Saccharomyces and Schizosaccharomyces ferments I’m used to analyzing? Would there be any horse sweat character?

My takeaway is that, wow, Cory tamed the beast! But at the same the time, the results are subtle and possibly best suited for a substrate that brings more of its own character to add extra dimension to the Brett aroma (such as fresh cane juice!). This reminded me of a Cape Verdean rum analysis I did years ago that was a bit of an outlier. It was so much more fun to drink the original spirit than the tale told by the samples. Typically, fraction 5 can pretty squarely tell you how extraordinary a spirit is, but somehow both Grogue and this Brett defy that. Their fraction 5 is a little weak.

Besides limiting all the wildcard off aroma Brett can produce, Cory hits another home run where he demonstrates another below average fusel oil producer. I did not expect this and wondered if it was noted anywhere in the literature. It seems to be the result of optimizing nutrition, but I won’t spill any of Cory’s secrets. This is important because the fate of much high value aroma in a distillate is bound to fusel oil due to bing less volatile. If you can reduce fusel oil, you can be justified in capturing more high value aroma that otherwise would be out of bounds.

The results appear to absolutely warrant further investigations in multiple directions, but at the same time I wondered if all the careful effort would be still best applied to a fission yeast? Once you master the skills required for maintaining high pH ferments, is there one yeast champion or will preferences emerge for specific substrates?


Fraction 1: Fruitiness from ethyl acetate but not concentrated to the point of non-culinary aroma. The clarity of the fruitiness makes it likely that there is not significant acetaldehyde. Possibly more ethyl acetate than some of the fission yeast rums.

Fraction 2: Predictably a more diminutive version of fraction 1.

Fraction 3: Extremely neutral as expected.

Fraction 4: Fusel oil is hard to detect and there is a possible start of fraction 5 aroma in this fraction. Very pleasant smelling and no fusel oil wraith. So easily palatable. This yeast could be an abnormally low fusel oil producer rivaling a fission yeast?

Fraction 5: No visible louche. Small fine precipitate on the surface, but no droplets. Slight animalic rum oil character, but no clear radiance. No clear estery character.

Fraction 6: Again, very similar to fraction 7.

Fraction 7: Very similar to fraction 8. Possibly a point heavier in a nondescript way. No obvious gustatory acidity.

Fraction 8: Fairly neutral with no significant gustatory acidity. No off aroma, no liabilities.

Stillage: A visual tint from the oak it was given as a maturation sketch. Very clean tasting and surprisingly neutral. No detectable gustatory acidity.

1 thought on “Birectifier Analysis of a Brettanomyces Rum

  1. Cory Widmeyer, The Yeast Whisperer.

Leave a Reply

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.

search previous next tag category expand menu location phone mail time cart zoom edit close