This weekend I made my first 15gal batch of a Summer cream ale. They go toward gifts mostly to friends for summer trips and such. I decided to play around with some fermentation temps to see how this yeast reacts. It is my house yeast for the most part, so I've been curious to see.
Each batch is exactly 5 gallons in 6 gal glass carboys. I used 3 packets of US-05, mixed dry and divided evenly into 3 (in case 1 pack was over/underattenuating), and rehydrated with 1 cup water each at 90 degrees. All were Oxygen infused for 1.25L per carboy of concentration. The yeast was pitched at actual fermentation temp, so there should be no variability in initial temperature swings.
Fermentation temp- 60 degrees- active kreusen appeared at hour 14.
Fermentation temp- 64 degrees- active kreusen appeared at hour 12.
Fermentation temp- 68 degrees- active kreusen appeared at hour 10.
It was pretty neat to watch how the temp changes how they lag. Both the 60 and 64 degree batches are showing the same rate of airlock activity (1 bubble/second), while the 68 degree batch is blowing off.
Once high kreusen is reached, I'll start taking daily gravity readings of each. In the future, tasting notes will be taken as well.
Reason for this experiment of sorts? I've always fermented on the cold side of the spectrum for all yeasts. It was in my old school of thought that colder fermentation temps curb some of the phenols that I personally find unpalatable. Then I read Jamil's book on yeast, and read that US-05 often has the opposite reaction to temps, and I got curious. We'll see if there's any merit to that...