Slightly different, but in the past I have distilled the yeast wash with glassware and achieved a foul smelling distillate. Rather than discard or
redistill multiple times, adding a SMALL quantity of KMnO4 with stirring to the cooled distillate and allowing to react fully (and until no "rotten
egg" or sickly smell remains) before redistillation has removed almost all of the nasty smells.
I suspect this to be due to the permanganate oxidising aldehydes and sulfurous compounds to higher boiling and less "aromatic" compounds (including
some ethanol), but have no evidence of course.
This approach is great for a very neutral spirit (or laboratory reagent) but would likely destroy any nuanced aromas you may be trying to create.
With other batches which require the flavours and aromas to be conserved, I have used freeze distillation. This method consists of freezing the entire
wash in a container with a neck (much like a large wine bottle), inverting the bottle over a secondary container, and allowing the bottle to defrost
and drip into the secondary container. In this process, a third of the original liquid is collected until the mostly-solid wash is discarded, most of
the yeast particulate being trapped in the ice-water mixture. The largest portion of the alcohol and volatile organics are concentrated in the
secondary container, and upon allowing the yeast to settle and pouring off the clear supernatant liquor, distillation yields a spirit with little to
no yeasty-ness while maintaining much of the desired aroma and flavour. |
