Increasing fermentation temp at the end

My understanding of the concept of raising the temperature at the end of fermentation is akin to conducting a diacetyl rest at the end of fermentation for lagers. The notion being that with just a few gravity points from expected FG you heat up the primary to ‘activate’ the yeast to ‘better’ cleanup fermentation by-products like diacetyl, acetaldehyde, etc.

It has been my consistent experience that for my ale fermentations there is no need to elevate the fermentation temperature at the end of the primary; the yeast ‘does its thing’ with no special need to elevate the temperature.

I suppose I should caveat that I always have healthy fermentations:

· Signs of fermentation much less than 24 hours from pitching

· Fermentation completes in a timely manner (e.g., less than 1 week for moderate gravity ales)

· Always reach my expected final gravity

· Etc.

Maybe for a ‘stressed’ fermentation increasing the temperature at the end of the primary would be prudent?

Raising the temperature at the end of fermentation will certainly not be detrimental.

Cheers!

 

I don't think there are hard and fast rules, but here are two reason to increase temps toward the end...
- Using a highly flocculant yeast strain
- Using a yeast strain prone to produce lots of diacetyl

 

IMO 64F is not too low for WLP001/Wyeast 1056, if you're asking if it will ferment at that temp.

 

I have never brewed with the White Labs version of California Ale yeast (WLP001).

I use the Fermentis version of California Ale yeast (US-05) a lot and that strain has a recommended fermentation temperature of 59 – 75 °F.

I would guess that WLP001 should ferment just fine at 64 °F.

Cheers!

 

Gradually raising the temperature is something I do often. Generally, a good time to consider doing it is 5-7 days into fermentation for a moderate gravity beer. Doing it sooner can create more fusels and esters than desired.

The beer will completely attenuate sooner without a penalty. The last few gravity points can take 10 days or as little as 2 days depending on the final stage temperature. I don't use sacc that makes much diacetyl, so "cleaning up" is not why I raise the temperature.

In the case of 001, there is no reason to raise the temp for a clean up, but you can raise it for the reason of an expedited finish. When your yeast flocs out at 75F, you know they are done eating!

 

You also increase fermentation activity, and it helps to blow off sulfur compounds. That last is more important for lagers than ales.

 

There has been some discussion about diacetyl (amounts) and yeast strains in this thread. While it is true that the amount of diacetyl produced is yeast strain dependent, most (all?) yeast strains will produce a fair amount (perceptible amount) during the lag/exponential growth phases of fermentation. The diacetyl will be reduced during the exponential to stationary phase of fermentation. Even a yeast strain like the Ringwood strain (Wyeast 1187) which is prone to produce a lot of diacetyl during the lag/exponential growth phase can result in a beer will non-perceptible amount of diacetyl if the beer is permitted sufficient contact time with the yeast to permit the stationary phase to go through fruition. Raising the fermentation temperature towards the end of fermentation with 1187 will accelerate the timeframe for diacetyl reduction.

Here is a nice write-up by Dr. Chris White on the diacetyl time line: http://www.whitelabs.com/files/Diacetyl_Time_Line.pdf

Cheers!