Questions about yeast/fermentation

[witster18]

last batch I brewed - I put it in the fermenter at about 8pm and the room was right around 70degrees. BUT, it was supposed to get cold that night and it did, and we hadn't turned on the heat(at all).. I woke up freezing at 5am, but I wasn't so worried about me as I was the beer. The thermostat read 56degrees in the room where I was fermenting.. I looked it was bubbling a bit, but barely.. I turned on the ehat and before long it was back up to normal fermenting temps.

after all was said and done the beer tastes great. kind of in between a hellas and a blonda ale... BUT THE yeast has givent he beer a bit of sour-estery flavors... AND THAT's one of the things I LOVE about it.

My question is... did the temp drop perhaps cause this? is this something that is done on purpose to change flavor profiles?

I'm a novice here so I don't know... the beer is sediment-free but a bit cloudy... of course it's only conditioned for one week so I suspect many characterstics will change..

 

[boydster]

What kind of yeast? Most ale yeasts like being in the low-to-mid 60's, and they can start to make off-flavors at warmer temperatures. Acetaldehyde is something that yeast will make as they ferment sugars, and at warmer temperatures they work faster and will even sometimes stop short of converting the acetaldehyde to alcohol in order to continue consuming more sugars as quickly as possible. That particular compound tastes sort of like sour green apple. Usually, once the fermentable sugars are gone, the yeast will go back and finish change the acetaldehyde to ethanol, and that flavor conditions out.

 

[witster18]

dry yeast... the pink pack I believe sm-15 or sm-51

 

[witster18]

make that t-58

 

[boydster]

Not sure, I usually ferment that one warm and haven't tasted what it is like with a cold ferment.

 

[witster18]

well, I think I may be trying to replicate this... kinda like a paulaner hefe thing twang