Fermentation Temperatures: Critical Periods?

I have a Chest Freezer + Ranco Controller + Thermowell. I keep all my ale fermentations at 66 degrees. I keep my ales in the primary for 3-4 weeks*.

My question: Once the "attenuative" stage is complete (typically 3-5 days for me...when the ferocity of the fermentation has substantially slowed down), is the temperature as critical? I would like to move my carboys out of the freezer to make room for the next ferment, but the closet I would keep them in for the 2-3 week "conditioning" stage may fluctuate between 65 & 72.

Bueller? dddddddddd

I'd like to go a little higher rather than a little lower. Wait a few days after attenuation stops and I think it matters less.

remilard said:

I'd like to go a little higher rather than a little lower. Wait a few days after attenuation stops and I think it matters less.

Click to expand...

Ok. The plan is to let it get through attenuation, pull it out of the absolute temperature controlled environment to let the next batch attenuate in there, and then return it to a 40 degree environment to cold crash for a week. From what I have read, the critical phase (as far as temperature control is concerned) is the attenuation phase.

It depends on the yeast strain but with my "cleanly fermented" beers I'll drop the temp to the low 60's in the swamp cooler and slowly raise the temps to ambient(68) as the yeast works through the sugars and then leave it at that temp for the remainder of primary. The theory is that the bulk of the flavors from fermentation are made at the beginning and then the warmer temps near the end help with attenuation and the cleanup of by-products. No science to back it up but I have no problems with this method. In summer ambient temp in my house is higher and the beers still taste the same so I would think you'd be fine with your plan

I think the most important timing for temperature control is from pitching through fermentation... the further in fermentation it goes, the less crucial consistency in temperature becomes, within reason.

The primary concern here is the production of fermentation by-products, such as esters, fusel alcohols, ketones, etc. that would throw you off from your intended flavor profile for that particular yeast and beer. I believe there is a bell curve for this throughout fermentation. Production can start during the growth phase and dies down as fermentation dies down (some of these even get "cleaned up" by the yeast as fermentation dies down). Once you get past about the 70% mark, the risk of producing these dies down significantly, IMO.

A secondary concern, once fermentation comes to a close and thereafter, is yeast cell decay. This is not necessarily autolysis and can cause compounds to be released from decaying yeast cells that can affect flavor and foam stability. In other words, long term storage on the yeast cake, post-fermentation, at higher temperatures can be detrimental. But as long as the temperature isn't all that high and the storage time isn't all that long, there is little concern for this.

Great answer...thank you.