Question about fermentation temps?

[bubbleboy]

I've brewed two batches... an IPA and a Pumpkin spice porter.

Both of these were PM and to be honest I didn't expect it to take as long as it did to cool down the wort. (I don't have a wort chiller, but it's next on my list to purchase)

Both times I pitched the yeast at 85 degrees F or slightly above.

The ambient temp varies between 65-68 degrees F.

I bottled the first batch last weekend and tasted (drank) about 6oz. It was the IPA and it's the hoppyest (is that a word) beer I've ever had the pleasure to drink. Not that it was bad, but I could taste the hops 20min after I finished drinking it. Other then that, it was good... just warm and uncarbonated. Didn't notice any off flavors, but I don't think I would have the expertise to know if there were any.

So my question has to do with pitching the yeast and fermentation temps. I know ideally I should chill the wort down to approx 70 degrees F before the yeast goes in (dry yeast, no starter). But I'm impatient.

If the ambient temp is 68 and I pitch the yeast at 85... the wort should cool down over the next few hours to just above the ambient and it would do 95% or more of the ferment at say 72-74 degrees. Is doing this going to cause off flavors?

I hope I'm making some sort of sense. Thanks in advance for any help.

Oh and great site! I've learned so much!!!

 

[cruckin78]

quick and easy cool down....

If your brewing from extract....I have a 5 gal brew kettle, (which has about 2.5 gal of wort) at the end of the boil.

I then fill my sink with ice, water, and salt (salt water get colder). I put my whole brew pot into the ice bath and stir it carefully for ~5-10 minutes (wort temp is about 85* at this point) then I pour it into my fermenter with the remaining 2.5 gal of water from the faucet that is cold from the faucet. This puts my entire temp to 70-73* perfect to pitch.

Pitching to hot causes off flavors....if you like your beer now....you will like it alot better when you do it correctly.

 

[bubbleboy]

This is where I get confused... is pitching it at too high a temp going to cause the off flavors, or is it fermenting at too high a temp the problem?

Or is it both?

 

[JonK331]

Both.

 

[thelastdandy]

just my 2 cents, but i believe there is a lag time after pitching where the yeast are "getting ready" to start consuming sugars. i don't know if i would recomend pitching that high, but if you are in a hurry for some reason i don't think you'll get the off flavors that you're talking about. as long as you reach your desired fermentation temps in an hour or two after pitching you should be alright. the actual fermentation temperature has a lot more to do with the off flavors.

 

[thelastdandy]

by the way, save yourself a bunch of money and make an immersion chiller. tell the guy at the hardware store what you are doing and as soon as you mention the word beer they are more than happy to help. very easy and much cheaper.

 

[tunoffun]

This is where I get confused... is pitching it at too high a temp going to cause the off flavors, or is it fermenting at too high a temp the problem?

Or is it both?

Both. But some of the substances you're going to be most concerned with (esters & fusel alcohols) are going to be more of a problem - according to what I've read - when the yeast are actively reproducing more than at other times. So that means that excessive temps at pitching and shortly thereafter have the potential to be more problematic than once the yeasties have effectively reached a stable mass and moved on to the business of actively fermenting the wort.

Keep in mind, however, that what's considered an 'off' flavor w/ one style may not be with another. I myself prefer to not use the term. Some beers benefit from certain compounds produced by yeast that in other styles would be detrimental.

That being said, I think most people would agree that 85 is way to high for just about any yeast, grain bill, or style... pitching or otherwise. I'd get those temps down to at least 75 if not lower if you can.

 

[Bob]

+1. Esters are the compounds which give yeast flavors and aromas, including off-flavors. Esters are produced in prodigious quantities during the phase of the yeast life cycle immediately following pitching. Many of those esters cannot be subsequently reduced during a later phase.

I find it worthwhile to get my bitter wort a few degrees below the desired ferment temperature before pitching. That way the initial spike in heat from all those yeast having the monocellular equivalent of sweaty monkey love has somewhere to go.

Cheers,

Bob

 

[Bensiff]

During the lag phase (around first 15 hours or so after pitching) you have a window where higher temps will not cause problems with things like esters, higher alcohols, diacetyl, etc. During this phase the yeast is busy collecting oxygen to desaturate fatty acids, uptaking phosphates, and beginning to break down glycogen in preperation for the growth phase where glycolysis begins to kick in, with fermentation phase being the real area where the beer flavors and alcohol are created. Until glycolysis generates pyruvate things like esters, fusels, diacetyl, and most everything else in brewing cannot be created. So as long as you got the temp down to the suggested range of the particular strain before the growth phase kicked in your temp will not be the cause of off flavors. That said, I respecftully disagree with those who said otherwise. But, at the same time, temp control is important and probably the single biggest thing you can control to increase quality.

 

[tunoffun]

During the lag phase (around first 15 hours or so after pitching) you have a window where higher temps will not cause problems with things like esters, higher alcohols, diacetyl, etc. During this phase the yeast is busy collecting oxygen to desaturate fatty acids, uptaking phosphates, and beginning to break down glycogen in preperation for the growth phase where glycolysis begins to kick in, with fermentation phase being the real area where the beer flavors and alcohol are created. Until glycolysis generates pyruvate things like esters, fusels, diacetyl, and most everything else in brewing cannot be created. So as long as you got the temp down to the suggested range of the particular strain before the growth phase kicked in your temp will not be the cause of off flavors. That said, I respecftully disagree with those who said otherwise. But, at the same time, temp control is important and probably the single biggest thing you can control to increase quality.

Again, I'm not arguing with your assertions, since I can't do so from personal experience, but I've read the exact opposite of what you're stating from numerous sources. For instance:

http://www.winning-homebrew.com/esters.html

But again - I'm only referencing what other people have said. You have as much a chance of being right as anyone else IMO. So no disrespected intended. I'm just curious where you get your info considering the people involved who say the opposite.

 

[bubbleboy]

During the lag phase (around first 15 hours or so after pitching) you have a window where higher temps will not cause problems with things like esters, higher alcohols, diacetyl, etc. During this phase the yeast is busy collecting oxygen to desaturate fatty acids, uptaking phosphates, and beginning to break down glycogen in preperation for the growth phase where glycolysis begins to kick in, with fermentation phase being the real area where the beer flavors and alcohol are created. Until glycolysis generates pyruvate things like esters, fusels, diacetyl, and most everything else in brewing cannot be created. So as long as you got the temp down to the suggested range of the particular strain before the growth phase kicked in your temp will not be the cause of off flavors. That said, I respecftully disagree with those who said otherwise. But, at the same time, temp control is important and probably the single biggest thing you can control to increase quality.

Thanks guys for the great responses! But this is exactly why I started this thread. Most of what I've read is along the lines of only pitching the yeast once the wort temp has reached 70 or less (Bob that's a great tip)...

Then I've read about their being a "window" of opportunity; or some beers actually benefiting from some fusel alcohol to a certain extent...

I'm still a bit but, I'm definitely going to cool the wort from now on just to play it safe.

Now I'm really curious how my beer will finally turn out

 

[Bensiff]

Again, I'm not arguing with your assertions, since I can't do so from personal experience, but I've read the exact opposite of what you're stating from numerous sources. For instance:

http://www.winning-homebrew.com/esters.html

But again - I'm only referencing what other people have said. You have as much a chance of being right as anyone else IMO. So no disrespected intended. I'm just curious where you get your info considering the people involved who say the opposite.

Yes and no to this article. I won't argue with Chris White, he has a PhD after all and I fully agree with what Chris White said; however, how the author used that information to make further suggestions I do not entirely agree with. The author doesn't understand what is being said fully so he is not altogether correct...if my understanding is correct. Mind you I have about four beers in me now so I'm not much for articulation right now. He isn't understanding the implications of everything he says, such as under oxygenating the wort...if you do that the yeast cell walls will be negatively impacted and as a result will be less capable of cleaning up diacetyl so recommending that as a means to increase esters isn't exactly the best path. His correlation between high temperature and AAT's is weird since he doesn't say how rapid yeast growth would increase AAT's just that more yeast growth equals more AAT potential. However, a pitch of healthy yeast with appropriate nutrients and oxygenation in the recommended temperature range will also result in plenty of yeast growth, albeit a little slower than a warmer pitch. I still believe the same holds true, temperature will not impact ester production in the lag phase; however, too fast a temp swing will stress the yeast so on that end it is not a good thing to pitch warm while still cooling to ferment temp.

I wouldn't call this a "window of opportunity" as I view pitching warm, especially while still cooling a mistake. However, sometimes in life you do what you have to do, so it is nice to know that there is a time frame that you have to play with that won't totally screw things up. I personally would let a wort sit covered for a day to cool before pitching warm...but that's just me and my trust in the fact I have never had an infection in 7 years of brewing. Well, before the beer makes me more wordy, let me know if I answered anything useful...if anyone has further questions I will try to answer it sometime this weekend.

 

[tunoffun]

Yes and no to this article. I won't argue with Chris White, he has a PhD after all and I fully agree with what Chris White said; however, how the author used that information to make further suggestions I do not entirely agree with. The author doesn't understand what is being said fully so he is not altogether correct...if my understanding is correct. Mind you I have about four beers in me now so I'm not much for articulation right now. He isn't understanding the implications of everything he says, such as under oxygenating the wort...if you do that the yeast cell walls will be negatively impacted and as a result will be less capable of cleaning up diacetyl so recommending that as a means to increase esters isn't exactly the best path. His correlation between high temperature and AAT's is weird since he doesn't say how rapid yeast growth would increase AAT's just that more yeast growth equals more AAT potential. However, a pitch of healthy yeast with appropriate nutrients and oxygenation in the recommended temperature range will also result in plenty of yeast growth, albeit a little slower than a warmer pitch. I still believe the same holds true, temperature will not impact ester production in the lag phase; however, too fast a temp swing will stress the yeast so on that end it is not a good thing to pitch warm while still cooling to ferment temp.

I wouldn't call this a "window of opportunity" as I view pitching warm, especially while still cooling a mistake. However, sometimes in life you do what you have to do, so it is nice to know that there is a time frame that you have to play with that won't totally screw things up. I personally would let a wort sit covered for a day to cool before pitching warm...but that's just me and my trust in the fact I have never had an infection in 7 years of brewing. Well, before the beer makes me more wordy, let me know if I answered anything useful...if anyone has further questions I will try to answer it sometime this weekend.

I appreciate your insight! Thank you very much for the clarification. I'm obviously new to this game, so I try to learn from others experiences whenever possible.