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-   -   Pitching temp vs fermentation temp (http://www.homebrewtalk.com/f14/pitching-temp-vs-fermentation-temp-121521/)

PavlovsCat 05-29-2009 04:31 PM

Pitching temp vs fermentation temp
 
Normally, after a run thru the CFC my wort - this being Florida- is around 80 degrees. I take the carboy inside for a while to let the A/C do it's stuff, and I'm usually pitching around 75 degrees. I then use the bathtub as a swamp cooler to achieve a lower fermentation temp.

My question is: if my recipe calls for ferm temps around 60-64 degrees, should I still pitch as usual or wait until the temp drops into the range and then pitch? But then my yeast temps (around room temp) will be way above the wort temp. Would this be detrimental? Should I have the yeast ready to pitch at around the 60-64 range. I guess the big question is should you condition the yeast first for the appropriate temp and the second would be: what's the best way to accomplish this.

hoppheadIPA 05-29-2009 04:34 PM

I always pith around 75 degrees. By the time fermentation actually begins, my swamp cooler has the temps well within range. Pitching at 75 will not hurt your yeast. Just pitch it!!!!

Trubadour 05-29-2009 04:38 PM

I go ahead and pitch if it's below 80* - sure, lower is better, but if you wait too long, you're increasing the chances of infection

ChrisKennedy 05-29-2009 05:12 PM

Waiting to pitch until it is at or below fermentation temperature is worth the risk of waiting for the beer to drop there. The growth phase is the period where the yeast produce most of their flavor compounds. This is more important for lagers and beers that are supposed to be pretty darn clean, but still useful for all beers.

hoppheadIPA 05-29-2009 11:06 PM

I dunno, I'm pretty sure they produce more flavor compounds after the growth phase, when fermentation is the most vigorous. Correct me if I'm wrong.

Yooper 05-29-2009 11:23 PM

I always pitch at fermentation temperature. I guess my thought is that yeast do love warm temperatures, but if fermentation starts at 70 or so, then the temperature will take even longer to come down to my desired fermentation temperatures. If fermentation only lasts 24-36 hours, it might take most of that time to get to the correct temperatuer an by then I'll have the esters already in the beer.

It's easy for me, though- my ground water is always cold, so it's not hard to get my wort to 62 degrees. If I get it a little cooler, that's ok, I can pitch cooler and let it warm up a little.

carnevoodoo 05-29-2009 11:32 PM

I take mine and get it to about 76 (as cold as I can really get with a CFC and the San Diego ground water) and then I put it into the freezer. Once it hits fermentation temps, I pitch yeast. A few hours won't hurt a thing.

ChrisKennedy 05-30-2009 05:59 AM

Quote:

Originally Posted by hoppheadIPA (Post 1353126)
I dunno, I'm pretty sure they produce more flavor compounds after the growth phase, when fermentation is the most vigorous. Correct me if I'm wrong.


As far as I can tell from trying to decipher Fix in "Principles of Brewing Science", much of the yeast by-products are influenced by the formation of acetyl coenzyme-A, which forms from pyruvic acid, which is formed prior to any real fermentation. Thus, this is happening during the growth phase. While the esters cannot be formed without the presence of alcohol and a catalyst, thus later in fermentation, their building blocks were formed prior to this, and it is when the building blocks are formed that temperature can play its biggest role, particularly during the growth phase.

So the diacetyl, esters, and fusels are technically formed later in fermentation, but the damage is done earlier in fermentation, while the pyruvic acid and acetyl coenzyme A are forming. I think, hah, somebody please correct ME if I am wrong.

CharlosCarlies 08-14-2009 12:22 AM

Quote:

So the diacetyl, esters, and fusels are technically formed later in fermentation, but the damage is done earlier in fermentation, while the pyruvic acid and acetyl coenzyme A are forming. I think, hah, somebody please correct ME if I am wrong.
Just wanted to bump this so as not to start a new thread on an old topic.

Can anybody else confirm/deny this? I typically pitch at 75F since my yeast is sitting at room temperature and well, our ground water is really hot this time of year.

I do ferment in a converted freezer w/ a temp probe, so it should get down to temps pretty quickly, but I had some pretty bad apple flavors in a batch of blonde ale (w/ Notty) a few months ago and want to figure out if high pitching temps might have been the culprit.

carnevoodoo 08-14-2009 12:31 AM

Quote:

Originally Posted by CharlosCarlies (Post 1486628)
Just wanted to bump this so as not to start a new thread on an old topic.

Can anybody else confirm/deny this? I typically pitch at 75F since my yeast is sitting at room temperature and well, our ground water is really hot this time of year.

I do ferment in a converted freezer w/ a temp probe, so it should get down to temps pretty quickly, but I had some pretty bad apple flavors in a batch of blonde ale (w/ Notty) a few months ago and want to figure out if high pitching temps might have been the culprit.

Very well could have been. If the yeast took off right away, they started doing their job at a temperature higher than ideal, and they are more vigorous in a higher temp environment, so that's likely.

If you have the converted freezer, you'll be better off cooling it down and then pitching for sure.


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