Have a stout with a distinct soy sauce aroma(less in flavor but still there) and its not undrinkable surprisingly but id prefer to understand what caused this and not have this happen again, im almost positive its a yeast/fermentation issue but the ferment seemed to go smooth, had solid temp control, beer was 1071-72 gravity down to 1011 pitched 16 grams of us05 dry sprinkled(maybe should have rehydrated) let it go 3 weeks and i got a keg of kikoman stout, yeast death? Under/over pitch? I am trying to figure it out
Could possibly be oxidation.
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Denny is right. Oxidation gives off a soy sauce flavor in stouts. Although these beers are somewhat tolerant of oxidation, they can get to the point of no return.
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Could be yeast autolysis but it doesn’t sound like it unless dry yeast was excessively old.
The non-enzymatic glycation of Maillard reaction products due to oxidative effects mimics the secondary moromi fermentation phase in soy sauce production and produces the same flavors and aroma. You can get meaty/umami off-flavors due to autolysis but the specific soy sauce notes in dark beers are an oxidation issue.
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Yeah! What he said!!
Do we consider “sherry-like” and “soy-sauce-like”, as flaws, to be from the same source?
Sherry-like is acceptable in an aged barleywine (and likely has some dark fruity esters), but not a fresh stout.
Matt, can you think of why this brew got so oxidized so quickly?
This is generally an oxidation issue but usually over a fair amount of time unless your beer was heavily oxidized early or throughout fermentation. Yeast uptake oxygen, so fermentation generally combats that problem. I could see this kinda happening if your racking process from kettle to fermentation vessel is aggressive and/or you added O2 for fermentation and fermentation was slow to kick off. Several days of oxygen exposure before fermentation really kicked off could cause this. Could be caused or aggravated by poor racking practices going from fermentation vessel to package.
Best example of this I’ve seen are older bottles of Three Floyds Dark Lord, which almost universally turn into soy sauce over time but we’re talking years.