Fermentation temps question

I'm sure this has been covered, but I can't seem to find exactly what I'm looking for.

Two weeks ago, I put together Northern Brewer's Caribou Slobber ale extract/specialty grains kit (basically a brown ale). Recommended fermentation temp is 65-75 degrees. For the first couple of days, while there was airlock activity, the temp was perfect, right at 66-67 degrees.

Now that the activity (at least what I can see in the airlock) has subsided, it's more like 62 degrees. So, is it most important that I'm in the temp range during those first few days, or do I need to find a warmer place while I let it sit in the primary for another couple weeks?

I know I'm being overly obsessive over a three degree difference, but I'm really looking forward to this beer. Thanks in advance.

Ideally you should keep the fermentation temperature as consistent as possible during primary fermentation. This is somewhat difficult as it is an exothermic process during active fermentation which you've already seen.

I think you're okay so long as there is no wild swing +/- 10 degrees. The other thing to watch for is a rapid change in temp...like going from a swamp cooler to a heated room is probably not the best idea.

I'm going to be a dissenting voice here:

Yes, to have primary fermentation done, you want the fermenting wort to be at the ideal temps for the yeast.

But it's also important for the yeast to stay at a good temperature for a week or so afterward as well - they're cleaning up fermentation byproducts during this phase that can lead to off flavors. If the yeast go to sleep before they're done, you could wind up with some off-flavors due to those byproducts that are left behind.

stratslinger said:

If the yeast go to sleep before they're done, you could wind up with some off-flavors due to those byproducts that are left behind.

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I usually keep my buckets at controlled fermentation temps in a swamp cooler for the first 5-6 days, and then take it out and let it sit at room temp (warm up a little) for the next 2-3 weeks. That's the idea, yeah?

This time of year I'm worried about the temps getting too cold and the yeast going to sleep like was previously stated. That said, it is still smart to keep things in check at the beginning when the fermentation can really elevate temps above ambient. BTW I subscribe to the swamp cooler method for cooling especially when you are talking keeping things only a little cooler than ambient.

Thanks for the tips, guys. Took all of the advice above, actually. I don't know what I was thinking, just put the primary in the closet out of habit. I moved it out into the room and it's gone from 62 to about 68 and seems to have settled there. Cheers.

One big problem that some brewers have is when the temperature drops and the beer has not finished fermenting.

A lot of new brewers think fermentation is over because of the lack of activity and go ahead and rack to secondary, and then find they have a high FG. Problem is the yeast go to sleep at low temperatures and drop, so when they rack to secondary, they leave all the yeast behind. Keep the beer within the temp limits until you confirm the beer is finished. Often it is a good idea to raise the temperature at the end to help clear up diecetyl and convert the last few sugars.

I brewed the exact same recipe almost two weeks ago. Not really thinking, I stuck it in my basement in a swamp cooler and the temperatures were pretty low (around 62). I tried to add hot water to the swamp cooler but it would only bring the temp up a little bit and didn't last very long. It did ferment and I got a good amount of krausen but I haven't taken a gravity reading to see where it's at....I'm kind of just hoping for the best. My beers that have fermented lower have tended to taste better so I'm hoping thats the case with this one. I'll probably bring the temperature up to the mid 60's for a day or two before I keg to make sure the yeast has finished its job.

I think you're fine provided that it's above 60. If it dropped below 58 or something I'd be more worried.

All great info, thanks.

Cincy, you planning on a secondary or skipping it?

woopig said:

All great info, thanks.

Cincy, you planning on a secondary or skipping it?

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I have never used a secondary. I always ferment for at least 3-4 weeks and then keg. Then again, I still consider myself a beginner (been brewing for about 2 years).

fyi - just checked tonight and my final gravity was at 1.011, although i think my hydrometer measures a couple points low. The krausen was still pretty thick but it appears it fermented fine at the low temps. It was at 59 degrees when I checked it.

Awesome, thanks. Put this together today, and all went well. It was my first full boil, but I think I did everything right. Came out with a little over five gallons and my OG was 1.062 (kit says 1.064), but that's pretty darn close. It's in the freezer right now at about 62 degrees, so hopefully my yeast starter will kick it up soon. Thanks again for your help.

I recently had a batch chill down in mid-fermentation. We had a snow storm here the weekend before Halloween which knocked out my power for a week. Without heat, brew shop temperatures dropped to mid fifties. A batch of Belgian Dubbel had been in the primary for about a week. I decided to give it an extra week to make sure fermentation had completed. Bottled it and tried some a few days ago. It tastes great (and just like previous batches), so the dormant period doesn't seem to have harmed things.