Fermentation Temperature Fluctuations

[brewstev]

My first batch has been in the carboy for a little over a week now. I had to go out of town for 5 days due to the holidays, and the temperature on the carboy was around 68F when I left. According to my instructions the optimal temperature is between 60-72F. Due to very cold temperatures my house has cooled down since I was gone, and I just noticed the reading of the carboy at 58F. Since being home I have increased the heat in my home and placed a blanket around the fermentor and increased the temp to 64F and the airlock is still bubbling but at a decreased amount. Will the decreased temp mean that i just need to wait longer to bottle?...and will these fluctuation in temps affect the taste of my beer?

 

[Arneba28]

Most of the fermentation probably finished up in the first few days that you were gone so I wouldnt worry about it too much. Once it got down into the 50s it slowed considerably so just give it a few extra days to finish up and clean up.

 

[marubozo]

I'd say you're somewhat lucky because lower temps are generally better. Even if the beer did drop down to 58, it took quite a while for that to happen while you were gone. And since active fermentation actually creates heat, I'd say your beer was in the ideal range of the low 60s for the first few days when temperature matters the most.

The lower temps may mean it takes a little longer for fermentation to complete, but this is by far nothing to worry about. Keeping it on the cool end of the fermentation target will ensure you get a nice and clean tasting beer. So, just let it run its course and after another week or so you may want to take a hydro reading to see where it stands. If it's near its target, take another reading in a day or two and see if it's moved. If not, you should be good to bottle and will have a great beer on your hands.