Optimal Fermentation Temp

I just installed a temp controller on a freezer in the garage, so now I can finally ferment my brew at the proper temperature. The funny thing is, even though I know that my family room's 78 degrees is way too hot, I don't really know what the optimal temperature should be. I'm sure the answer is, "Well, it depends", but where can I find some guidelines on what temp I should be fermenting at?

Thanks in advance!

You're right - totally depends.

Generally, lower 60's is great for most ales. Cooler temps you'll get cleaner ferments. Warmer temps (i.e., closer to 70) will start getting some yeast character.

For info, I would look at recipes of styles you're trying to brew...most indicate ferment temps. Or search for the yeast strain you want to use. You'll quickly get a feel for it.

PS - Good job on making fermentation temp control a priority!

Most "standard" ales, I do at 64-66*.

Lagers I hold at 50*.

Belgians I ramp from 62* to 80* over 10 days.

Just as an anecdote, I've used US-05 for a handful of IPAs at ~68-70 and they weren't noticeably different than fermenting at ~63-65. I'm actually currently leaning toward the higher temps for the style for a faster turnaround without flavor impact.

AmandaK said:

Most "standard" ales, I do at 64-66*.

Lagers I hold at 50*.

Belgians I ramp from 62* to 80* over 10 days.

Click to expand...

This, although I do most of my standard ales in the 61-63 range. Might ramp them to 66 or 67 the last day or two of active fermentation.

The temperature depends on the yeast. All of the yeast manufacturers will give you stain specific fermentation temperatures.

As an example, from the Wyeast and White Labs websites:

YEAST STRAIN: 1968 | London ESB Ale™
A very good cask conditioned ale strain, this extremely flocculant yeast produces distinctly malty beers. Attenuation levels are typically less than most other yeast strains which results in a slightly sweeter finish. Ales produced with this strain tend to be fruity, increasingly so with higher fermentation temperatures of 70-74°F (21-23° C). A thorough diacetyl rest is recommended after fermentation is complete. Bright beers are easily achieved within days without any filtration.

Origin:
Flocculation: Very High
Attenuation: 67-71%
Temperature Range: 64-72F, 18-22C
Alcohol Tolerance: 9% ABV

(Notice it tells you that the beer will be increasingly fruity with higher fermentation temperatures of 70-74 degrees).

and

WLP001 California Ale Yeast
This yeast is famous for its clean flavors, balance and ability to be used in almost any style ale. It accentuates the hop flavors and is extremely versatile.
Attenuation: 73-80%
Flocculation: Medium
Optimum Fermentation Temperature: 68-73°F
(20-23°C)
Alcohol Tolerance: High

In general, the lower temperatures produce the "cleanest" flavor while fermenting at the higher range of the yeast strain's optimum temperature will produce more fruitiness depending on strain.

I ferment most ales at 62-64 degrees, but will go higher for certain yeast strains.

Most of the ale strains I use work fine at 60F. I tend to keep my controller set to that. Most fermentations only go 3-4 degrees warmer than the controller but big beers with can get as high as 10. I like to move them to room temp when fermentation slows just like I do with my lagers.

I had my apartment set for 68 but was getting a little too much of the yeast character. I forgot that during fermentation the temps rise a bit probably putting it closer to a 70-72 fermentation. As soon as I dropped my apartment temp to 65 I got a cleaner tasting beer. That's been mainly with the 1056/WLP001

Awesome information, folks - thanks so much. I visited the Wyeast Labs website and found that my 1056 should be 60-72 (a pretty wide range, it seems), but it also says that "mild citrus notes develop with cooler 60-66°F (15-19ºC) fermentations." Since I think this will enhance the Apricot flavoring I'm using, and since I know the fermentation process will actually generate heat, I think I'll set the cooler for 62 and see how it turns out.

I just want to point out too that the temperatures given on the yeast manufacturers websites are the fermentation temperatures, not the ambient air temperatures. WLP001 has a listed "optimal temp" of 68-73°F. This means that the active fermentation should be in this range, which means your ambient temp needs to be considerably lower (since fermentation is an exothermic process). Obviously, with a temp controller you can set things up so that you are regulating the temperature of the fermentation....but this is why those of us without a temperature controller will indicate we ferment at temperatures lower than the recommended yeast temps.

Lately I've noticed that my beers are not finishing at 63-65 even after 3 weeks. They have typically gotten to about 1.018 to 1.020 and then stalled, but after the temp gets into the 70's they finish up in less than a week. Maybe it is due to using extract.