Fermenting at 60 or below -- is this just slower, or also bad?

[peripatetic]

Hey there,

Quick question -- my cellar (which had been consistently at 68 all summer) is now closer to 61 or 60. Other than simply slowing fermentation, will this have negative impact on the beer?

And, if this is really bad, do I have any choice other than to build a fermentation chamber?

Thanks for any advice!

 

[BigEd]

You will need to check the recommended temperature range of the yeast you are using. As long as the fermentation is within the yeast's temp window you should be fine. At the lower end the yeast will likely work more slowly but if you are below the temp floor of the yeast it may virtually stop.

 

[HOOTER]

You will need to check the recommended temperature range of the yeast you are using.

Agreed. Some ale yeast strains ferment well at cold temps. However, I have noticed in my own experience that when you are fermenting at the low end of the temp range attenuation can be reduced a bit.

 

[Chad]

Depending on the preferred fermentation temperature of the yeast and the style of beer you are making, you might end up with a better beer than you would at higher temperatures.

Temperature has a lot to do with ester production, which you don't really want in a clean, American-style ale. In an English ale you might want some, but still not excessive, and you'll probably still get plenty from whatever strain of yeast you are using. If you are making a Belgian or other estery, yeast-driven style of beer then you are going to be very disappointed. Your beer will lack many of the characteristic flavors if that style.

With that said, however, even if you are slightly below your yeast's preferred temperature range you will most likely make a very clean beer, just a little slower than you might have at higher temps.

Chad

 

[peripatetic]

"attenuation can be reduced" -- sorry, noob question: does that mean that not all of the sugars get turned into alcohol, and I'll end up with a higher FG?

I checked the yeast that I just pitched today (White Labs Trappist (WPL500)) and it says that optimal is 65-72°F, and that Lower temperatures (under 65) will result in less fruity and more earthy beers. So, I brought it upstairs and it's in my ~68* kitchen now instead. Thanks for the advice!

 

[Chad]

Depending on the preferred fermentation temperature of the yeast and the style of beer you are making, you might end up with a better beer than you would at higher temperatures.

Temperature has a lot to do with ester production, which you don't really want in a clean, American-style ale. In an English ale you might want some, but still not excessive, and you'll probably still get plenty from whatever strain of yeast you are using. If you are making a Belgian or other estery, yeast-driven style of beer then you are going to be very disappointed. Your beer will lack many of the characteristic flavors if that style.

With that said, however, even if you are slightly below your yeast's preferred temperature range you will most likely make a very clean beer, just a little slower than you might have at higher temps. Perhaps try raising the temperature a bit (maybe 5°) about 3/4 of the way through the fermentation. Kind of like a diacetyl rest for lagers, but really more of a chance for the yeast to clean up after themselves and finish out the fermentation so you aren't under attenuated.

Chad

 

[peripatetic]

If you are making a Belgian or other estery, yeast-driven style of beer then you are going to be very disappointed. Your beer will lack many of the characteristic flavors if that style.

With that said, however, even if you are slightly below your yeast's preferred temperature range you will most likely make a very clean beer, just a little slower than you might have at higher temps. Perhaps try raising the temperature a bit (maybe 5°) about 3/4 of the way through the fermentation. Kind of like a diacetyl rest for lagers, but really more of a chance for the yeast to clean up after themselves and finish out the fermentation so you aren't under attenuated.

Heh. I'm making a Chimay Blue clone. I don't want to be "very disappointed!"

So, I think I'll keep it in a slightly warmer place. Thanks for the great information.

 

[mr_goodwrench]

My basement is also quite chilly and well below the recommended temperatures for my yeasts. I have a storage tote that I have my fermenter in and roughly 3/4 filled with water. There is a submersible aquarium heater and a small submersible fountain pump to circulate the water in there. Much simpler and less expensive than building a fermentation cabinet.

 

[HOOTER]

"attenuation can be reduced" -- sorry, noob question: does that mean that not all of the sugars get turned into alcohol, and I'll end up with a higher FG?

Essentially. Not only can fermentation be slowed, but FG can end up a bit higher than intended. I personally have found that my brews that ferment at the low end of the recommended temp range finish a little higher than similar gravity brews that ferment in the middle/top of the temp range. Maybe there are certain sugars that just can't be consumed by the yeast in cooler temps for whatever reason. Not sure of the science behind it really so maybe someone can come along and enlighten us. This is solely based on personal experience.