Raising temp after reaching final gravity

I'm going to start fermenting in a room that's basically a separate apartment. We normally don't run the window unit AC, but I'm going to run it now for fermentation.

It seems from what I've read and heard that slightly higher temperatures after you reach final gravity will aid in "cleaning up" the beer.

My question is: for American ales, will I get any negative yeast activity or other effect from not keeping my fermentation room quite as cool after I hit my final gravity?

For example, let's say I ferment an APA using California ale yeast at 68F, and after 5 days I reach final gravity. Then, still in my primary fermenter (I do primary only) I let it rise to 72F or 74F for a couple of weeks and then bottle. Am I likely to get any off flavors?

Any help?

You shouldn't get any off-flavors if you've hit final gravity before raising the temp. Most of the yeast-derived flavors are produced during the early parts of fermentation.

I often do this when switching from an american ale series (58F with pacman yeast) to a belgian series (pitch at 65, let it rise to whatever it wants). As long as the pacman beer is mostly at terminal gravity, I'll still get the characteristic clean finish from the yeast if I store it at 70ish for a few weeks.

Thanks. That's what I was thinking, but I wasn't sure.

What's the highest you've let an American ale finish at? Just wondering if you let your Belgians run up into the mid or high 70s with an American ale finishing.

I do what you describe every time I ferment. I swamp cool my primary at 66 or so for most ales, and at about the 4th day or so, I'll pull the primary out of the swamp cooler and let it free rise to ambient temp. I normally pull it out of the cooler when it seems like the yeast have finished the bulk of fermentation for a few reasons. No.1 I only have to tend to a swamp cooler for 3 or 4 days, and No.2 This "let the yeast clean up" makes sense to me, and this practice allows both of those ideas. I have been very happy with the results. No hot alcohols of any kind or off flavors, and the beers have attenuated fully every time.

The only issue I can think of is that if you increase the temp for a diacetyl rest then you want to maintain a high temp....be careful of fluctuating temps at night.

Well, if what you're describing is a diacetyl rest, then one thing you stated isn't quite right. You don't want to wait for it reach final gravity before letting the temperatures come up, you want to start the rise towards the tail end of active fermentation, so the yeast "finish strong," so to speak, and don't leave a bunch of by-products of fermentation, one of which is diacetyl, behind to make your beer taste weird. Of course, judging exactly when to do this is not exactly easy, so it's something you'll just have to learn from trial and error with different yeast strains and recipes.

If, on the other hand, your question is simply whether you can let the temperature go up once fermentation is complete, then the answer is simply yes. You'll need to keep it within a reasonable range of normal room temperature, but there is much less concern about the flavors your yeast will leave in your beer due to temperature fluctuations once the yeast have largely exhausted the available sugar in your beer. So if you want to let it sit at room for a couple of weeks and bulk condition, you shouldn't run into any issues, at least I haven't when I have done so with my beers.

Also I saw a great pic of someone using some blankets and garbage bags to keep a fermenter chilled on a hotel room AC unit during an out of town brew day. You shouldn't have to cool the whole room just for one bucket.

If there is a bathtub in this apartment you could use that as a swamp cooler. Freeze milk jugs filled with water to cool the bath/swamp water. You might not need to use the AC. If you are just using the ambient air temp of 68 the actual ferment temp will be significantly higher.

aggieactuary said:

I'm going to start fermenting in a room that's basically a separate apartment. We normally don't run the window unit AC, but I'm going to run it now for fermentation.

It seems from what I've read and heard that slightly higher temperatures after you reach final gravity will aid in "cleaning up" the beer.

My question is: for American ales, will I get any negative yeast activity or other effect from not keeping my fermentation room quite as cool after I hit my final gravity?

For example, let's say I ferment an APA using California ale yeast at 68F, and after 5 days I reach final gravity. Then, still in my primary fermenter (I do primary only) I let it rise to 72F or 74F for a couple of weeks and then bottle. Am I likely to get any off flavors?

Click to expand...

I pretty much have been doing that with good results. I keep the brew in my swamp cooler and control the temp very carefully. But after a week when I brew again, I pull the fermenter out and let it get to ambient temp for the next two weeks. It has been about 75. After the initial fermentation is over I do not think that it makes much difference.