Fermentation Heat Question Please Help!

[Labradork]

Folks,

I just started my fourth ever batch of beer, a robust porter. It had an O.G. of 1.07 and was an extract recipe with specialty grains. The yeast is Safale S-04. It started pumping out CO2 within 6 hours, and by 12 hours had filled my carboy and blow-off tube with krausen and was bubbling steadily and quickly. The water in the bucket the hose goes into now looks darker than Guinness.

My concern is the temperature the fermentation is happening at. It went from 68 degrees last night to about 78 this afternoon. This is in a room maintained at 67-68 degrees with the curtains closed and a windbreaker over the carboy so no light can hit it. The outside temperature is in the 50s. I'm figuring that the temperature increase has to be due to the very rapid fermentation. I've since put the carboy in a water bath and thrown some ice in with it, as well as wrapped it in a wet T-Shirt.

My question is, since the temp was up around 78 degrees for most of the day, can I expect any ill effects to the beer?

Labradork

 

[homebrewdad]

You're right to be concerned, and you took good measures. For future reference, fermenting beer typically adds a good 5-10 degrees F to the ambient temp.

78 is pretty warm for most yeasts. Expect some additional esters to be produced, and perhaps some fusel alcohols (hopefully not). These may give your beer a "hot" taste, which age may or may not help.

Try to keep your temps no higher than the mid 60s, and life will be good.

 

[mattd2]

With what homebrewdad said at least you had a good style for this to happen in. the larger amount of dark malts should help cover up any off-flavours from the high ferment temp.

 

[Labradork]

Homebrewdad, Mattd2,

Thanks for the speedy replies. Looking over my notes, I would guess that the wort had been at that temp for most of 12 hours. The water/ice bath and the wet t-shirt took the temp down pretty quickly and it's at about 67 now, 12 hours later. I am hoping that not too many esters were created and that the fusel alcohols went out the blow-off tube. I've never seen such a dark and complete coating of brown junk on the inside of my carboy and blow-off tube. I'm grateful it's not in contact with the wort. I suppose we won't know the full extent of the damage until I crack the first one open in a couple of months.

I will consider this mistake as a learning opportunity and not make it again.

Thanks again,

Labradork