... you bottled with 6tsp of 80% lactic acid ...
... When I have purchased acid malt, the bin holding the grains often has a vinegary/acidic pungent odor. You used it at rate of 27% of your fermentables (that percentage uses the mass of the extracts). ... When used to "sour" the beer, it can give a very tangy flavor, that is more biting than sour ... it's not ideal. ...
It did get too sour for a mellow gose, but not ridiculously sour (it's tame compared to stuff like
this or
this). The acid malt, at 15% grain bill by my calc., was mistakenly not ground and thus probs contributed little to anything, and the lactic acid at bottling was 80%, not the usual 88%, and 'only' ~4ml (small tsp) per .5L/17oz. The off-taste was distinct, aromatic, and not related directly to lactic acid (I dissolved the lactic acid in water and tasted. No aroma/off-taste; just sour). It's possible the malt husks alone had enough pungency to contribute off-tastes, but
I didn't detect this off-flavour in the wort suggesting it arose when fermenting/bottling.
+1 to what
@bucketnative said. ... Highly recommend using Bru'n Water ... my Gose that is fermenting now only used .16lb of acid malt. Total grain weight was just over 10 lbs and this was for a 5 gallon batch. ... You say you've tasted #2 off flavor is someone else's homebrew. What kind of beer was it that you tried? Do you know any details about the recipe?
I'm looking at
EZ Water Calculator, and when I get time I'll research how unbalanced water contributes to off-flavours in fermentation. Possibly, the acid malt dropped wort pH below where S-05 can handle 24C without excessive fusels?
The other 'beer' I've tasted with a similar off-taste was my buddy's underage attempt at acquiring alcohol. He used white sugar, lots of flaked unmalted/unmashed oats, poorly mashed barley malt, and unpasteurized lingon- and juniper berries pitched with baking yeast. The abomination was fermented without a proper air seal at a fluctuating 25C and capped at the last second in PETs for carbonation. It ...worked? Ish? But turned sour from lactobacillus in the lingonberries I guess.
My guess is the off-taste is some kind of fusel since it smells like a mix of paint thinner and machine lubricant (if you went to a train museum, you'd go "Ah, THAT smell!").
... Did you just steep the acid malt in the boil kettle?
The recipe said mash the acid malt for 45min@~68C in a small pot, so I did. ...Uncrushed.
+1 for using Lactobacillus ... consider starting with MUCH more simple recipes ...
The recipe was based on
this. I probs won't mess with lactic again for a while, but maybe... I got a huge carboy collecting dust, and I recently drank
this and got blown away by the fermentation. So I was thinking I could try to steal Alvinne's secret 'Morpheus Yeast' from a bottle, mimic their ale, and see what abomination is inhabiting the carboy come spring. Rumour has it 'Morpheus' isn't a brett but two abnormal S. Cerevisae and a lactic bacteria str
ain.
General follow-up:
I based my gose on this recipe but 'accidentally' seasoned with lactic 'to taste' at 4ml instead of 0.8ml per bottle (500% vs. recipe). Storing the bottles for a month markedly reduced the off-taste but didn't remove it. Still a 1/5 star beer - barely drinkable.
I've also made this elderflower mead and the part i fermented with S-05 has a slight trace of the same off-taste when completely fresh (haven't tasted the non-S-05 part). I've made an APA and a strong spruce ale with S-05 @same temp (23C/74F) that did not have the off-taste. The off-taste, which was not present in the wort or must, is reminiscent of paint-thinner or machine lubricant, which leads me to believe it's a fusel alcohol caused during fermentation. The fusel was very strong smelling in the hop bag used for lemon zest in my mead, and this gose also had lemon/orange zest. The mead had a low ferment pH due to added grape juice, the gose likewise due to a lot of added acid malt. My theory is that either a low pH and high temp causes S-05 to produce excess fusel alcohols, or the aromatic oils in citrus zest cause off-taste/fusels when fermenting at 23C w/ S-05, or both are culprits.
Conclusion:
Maybe don't use S-05 in sour worts at high temps, sour worts at all, and/or worts with even a trace of lot of citrus peel oils.
Edit:
After consulting google, I can only see people praising US-05 for fermenting out sours, including kettle sours and artificials. The plot thus thickens. Esp. since I fermented both the mead and gose first at ~18C and then at ~23C, which is well within the range of US-05 for both sours and unsours. Could a trace of citrus oil, the common denominator in the mead and gose, be the culprit? And if so, why would citrus peels be commonly used? Very strange.
