June 27, 2017

You know what? : fusel alcohol


I found what I brewed was not a beer, but a vinegar... 
a historical failure I've ever had.

lesson:
you cannot brew beer without a freezer when late June's average temperature in your city is above 29 degree Celsius.

update(2017_07_10): 
I did some research and deduced that the unpleasant sourness came from fusel alcohol. It smells like a nail polish or a paint thinner, tasting chemical(solventy) and gives a headache. The description was quite similar to what I experienced. 
fusel alcohol can be produced by,
  1. too high fermentation temperature(definitely)
  2. the yeast sit too long on the trub(probably. days were very hot, the primary fermentation should complete in 3,4 days but I kept them waiting 7 days as usual)
  3. high gravity wort lead to the beer with an overproduction of acetate esters(fruity and solventy)(the FG of this saison was over 1.04, absolutely higher than usual. and an input of candi sugar) 
related articles

according to Scott Janish's post, beer aging possibly contributes to decrease esters. Before dumping the whole batch, beer aging is my last resort. 

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