39467Re: strong yeast odor after fermentation
- Oct 15, 2010Thanks for the reply ZB. I have been thinking that I needed to study up on yeast nutrition and have been meaning to read the Lallemand yeast nutrition guide in Harry's library for starters. I've been throwing DAP in at intervals, but not really knowing what I'm doing.
Questions: Where you said: "When a still wash sits, especially when hot, dissociation can form acids, which react with the alcohol to form esters, which are flavor and smell elements of the spirit."
Are you saying that if I strip a batch and the distillate sits on the shelf for a while, it can degrade from acid in the distillate?
Reason I'm asking is that I have to strip three batches to make a spirit run, and it might take me several weeks to get to that point. Should I be adjusting the PH closer to neutral for storage before the first spirit run? I've never checked the PH at this point.
Will potassium carbonate do the same thing or does it have to be sodium bicarbonate?
After the first spirit run at 190 proof +-, is PH an issue anymore?
Lots of questions, thanks for your patience!
--- In firstname.lastname@example.org, "tgfoitwoods" <zymurgybob@...> wrote:
> It's just a guess, but one from a fair amount of experience. I think
> what you observed with the sulfur (hydrogen sulfide, probably) smell was
> a great lesson in yeast nutrition. With insufficient/incorrect
> nutrients, you tend toward bad flavors and smells. Fix that and you
> fixed the smells.
> Of course, some yeast and worts generate some off smells/tastes in a
> healthy situation, and this is what lagers and lagering is all about.
> When a still wash sits, especially when hot, dissociation can form
> acids, which react with the alcohol to form esters, which are flavor and
> smell elements of the spirit. The bicarb just raises the pH, and (more
> or less) stops those acids from forming, and so retards ester formation.
> If you're making "brown" booze, with ester profiles that you've worked
> hard to get, bicarb will flush your efforts down the toilet.
> Bicarb is mostly for vodka runs, and only for the second-or-more (low
> wines) runs. In many cases raising your pH in a stripping run, with
> yeast nutrient present, will give you the dreaded "blue ookies", blue
> copper compounds (Schweizer's reagent) in your spirit.
> Zymurgy Bob, a simple potstiller
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