The Temp At Which We Pitch | exBEERiment Results!

I recently performed an xBmt comparing a beer pitched at 64˚F to one pitched at 74˚F, same wort, split batch. The results surprised the hell out of me, check them out for yourself on my website!

Very nice write-up (as usual) and I'm actually not surprised by the results, but I do think that tight control on fermentation temperatures and ability to hit desired temperatures play a huge roll in this. Nevertheless, very good news since I've been pitching my lagers a tad warmer that fermentation temperatures simply due the fact that I can't chill using tap water to where I would want it. Everything I've tasted out of the fermenter (still young) has tasted fantastic - especially my most recent dunkel. Anyway, thanks again for sharing your exbeeriments with us all. I'm interested in doing one similar to one you just did (belma apa brewer comparison) with some friends here. We'll see if I can get it organized

Very awesome blog page btw. Loving the xBmts'. I usually just chill my ales down to 70-75 anyway but until this last year haven't had the ability to have a spare fridge/freezer to more easily have temp control. That has made the most difference in my brews anyway.

Keep up the xBmts sir!

Thanks that eases my mind somewhat!

Well, that'll make brewing ales somewhat easier for me. I appreciate your experiments! Maybe I should run such experimental batches too, right now all my split batches are yeast A vs yeast B.

Well written! Thanks!

Nice write up... And nice site! I mainly use dry yeast, I wonder if this applies? I'll have to try it I suppose. Normally I do as you do, pitch at a couple of degrees below fermentation temp but I the summer it's hard to get the wort that cool around here so I'll stick the carboy in the chamber overnight and pitch in the morning... Perhaps I don't need to do that...!

Very interesting, thanks for the write up!

Another informative exBEERiment. Thank you. I have pitched "warm" a few times without noticeable deleterious effects, but then I don't have a particularly well trained palate. I do have a controlled fermentation chamber. Now I can save the chill time without feeling like I'm cheating.

Brew on

I like the experiment and I can concur with the results for the clean American yeasts. I do wonder if the result would be the same if you redid the experiment with an English yeast that is known for producing some residual esters.

That's cool.

I've always thought that a pitch around 70F was good. Pitching closer to fermentation temperature would be better.

The only time I've had a pitch temperature problem was my first beer, pitched at 100F. It was a green apple bomb.

Great blog! Thanks for the time you put into these experiments; they benefit us all.

Oginme said:

I like the experiment and I can concur with the results for the clean American yeasts. I do wonder if the result would be the same if you redid the experiment with an English yeast that is known for producing some residual esters.

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Since initially analyzing the results of this xBmt, I've made 2 batches using WLP002 pitched at 74˚F then placed in my ferm chamber set to 65˚F... no noticeable esters at all. Given how incredibly anecdotal that evidence is, I plan to repeat a more controlled xBmt using not only lager and hybrid strains, but strains known for throwing off more esters. Stay tuned!

I have mixed feeling about the value of and experiment like this. If WLP090 is your house yeast, learning how it work under different situations in your brewhouse will make you a better brewer. The trouble is that between dry and liquid and different labs propagating a huge variety of strains, it's all but impossible to draw any conclusions from someone else’s experience under conditions that may not duplicate yours. The best takeaway here is that the status quo will always have exceptions, but don’t discount that in most cases it was based on the broad experience of many brewers over many years.

P-values? Wow. You must be using Student's t-test, both due to the small sample size and the sheer awesomeness of using Student's T on a beer related experiment?

My big concern with changing the status quo on this one is with (as you note) brewers lacking a temperature controlled fermentation chamber. Your chamber might get that warm pitch down by 10F in just a couple of hours. It might take several hours for that to occur in a basement.

This Danstar article suggests that a warmer pitch (and lag phase) causes more rapid yeast growth which would make less Co-enzyme A available for ester production during fermentation.

There are a lot of variables that play into ester production: temp, pitch rate, yeast health, yeast strain, OG, and oxygen. My take away from this is that pitch temp and lag phase temp maybe less sensitive variables than the other ones.

This is a nice experiment/write-up, but I would really hold off on drawing any strong conclusions from it. It is essentially one data point.

Yeast strain, pitch rate, O2 levels all play a roles to different degrees with the dozens and dozens of strains available. Just because one beer turned out well pitched warm with a non-expressive strain really shouldn't sway anyone from moving away from well-established brewing practice (millions of data points).

g-star said:

This is a nice experiment/write-up, but I would really hold off on drawing any strong conclusions from it. It is essentially one data point.

Yeast strain, pitch rate, O2 levels all play a roles to different degrees with the dozens and dozens of strains available. Just because one beer turned out well pitched warm with a non-expressive strain really shouldn't sway anyone from moving away from well-established brewing practice (millions of data points).

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Those "millions of data point" are non-experimental, and therefore are anecdotal. That doesn't mean there isn't value to conventional wisdom, as you note, but it does mean that we should resist the temptation to treat it as gospel.

Interesting experiment, not what I would've expected either. While not definitive, it is certainly thought-provoking and warrants repetition.

I wonder if similar results would be found with different yeast strains? Different styles?

Barley_Bob said:

My big concern with changing the status quo on this one is with (as you note) brewers lacking a temperature controlled fermentation chamber. Your chamber might get that warm pitch down by 10F in just a couple of hours. It might take several hours for that to occur in a basement.

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Having very little actual scientific basis behind my thoughts, I would think that (as mentioned in the blog post) the big difference wouldn't necessarily be the time it takes for the chamber to bring it down, but more the ability of the chamber to manage temp at / near the time of peak fermentation...and that by pitching cooler, those without this ability get a better "head start" against peak fermentation temp getting out of control.


These concepts cross streams to some degree, obviously.

I believe it was you that did the temp controller probe placement exbmt. But i would think that would play a big part in this as well. I remember seeing a exbmt for optimal temp controller probe placement. I think the side of the fermenter was best with some kind of insulation between the probe and the fridge. I would also think that would be tough if you had multiple batches going too.

Ha! I've been vindicated! Of course, I never really argued for a 70-75* pitch with anyone, that's just what I did and my beers tasted good enough for me.

Great post. I've been keeping an eye on your blog since I found it here a few months ago, great info and love the experiments you do to get semi-conclusive information about the various topics we often all don't agree upon. Getting ready to try your lagering technique here later this month, could save me months of time tying up the fermentation chamber if it works for me!

Brulosopher said:

Since initially analyzing the results of this xBmt, I've made 2 batches using WLP002 pitched at 74˚F then placed in my ferm chamber set to 65˚F... no noticeable esters at all. Given how incredibly anecdotal that evidence is, I plan to repeat a more controlled xBmt using not only lager and hybrid strains, but strains known for throwing off more esters. Stay tuned!

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10 degrees and 4 hours is really nothing. I think it would be nice to see some crowd-funded exbeeriments where you might actually risk loosing a batch.

Beer + Science. The ultimate combo.

Nice experiment, but I have to admit I'm not that surprised. Given the fact that you are chilling the wort while the yeast is reproducing, and that they appeared to be nearly the same temperature at 24 hours, I would have been surprised at dramatic differences between the two batches. It would be really interesting if you let the experimental batch really get going at 75, and then ramp down to more typical ale temps. I would imagine you'd really see a difference then (since I've done it, albeit not controlled or intentional...)

Nice work.

I have one question. What was the temperature of the yeast starter you pitched? Was it the same for both batches? Just curious as I try to have my starter temperature the same or slightly lower than my cooled wort. Thanks.

Pretty nice to know. The ground water where I live is pretty hot most of the year, those last 10 degrees are a pain in the ass, especially when I run out of ice. Definitely easier to just pitch at 70+ and let my fermentation chamber drop it to 64F.

I see one issue in this experiment: Was the temp measured with those sticky surface termometers? Temp distribution inside the fermentor would go as follows: warmest top center and getting colder the more you go to the sides and bottom. Therefore, you took the temperature in the coldest spot of the fermentors, which is also the first one to "feel" the temp drop. Then, that pitching temp you were measuring was the "most different" between both fermenters. Then, maybe both pitching temperatures (average temp in the whole volume) were actually more similar than you measured. Did you take that into account?

I clicked on your experiments link and BAM! one hour later i realized i missed my train.

I think the main reason that the advice of pitching at below target temp is due to people fermenting in ambient conditions. It will take a fermenting beer much longer to go from 74 degrees to 66 if the basement is 65 vs in a fermentation chamber that problaby sends air temps down much lower for short periods.

hunter_la5 said:

Interesting experiment, not what I would've expected either. While not definitive, it is certainly thought-provoking and warrants repetition.



I wonder if similar results would be found with different yeast strains? Different styles?

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I certainly plan to repeat this xBmt with different strains, beer styles, etc. I'm most excited for the results when using lager strains.

BigPerm said:

Beer + Science. The ultimate combo.

Nice experiment, but I have to admit I'm not that surprised. Given the fact that you are chilling the wort while the yeast is reproducing, and that they appeared to be nearly the same temperature at 24 hours, I would have been surprised at dramatic differences between the two batches. It would be really interesting if you let the experimental batch really get going at 75, and then ramp down to more typical ale temps. I would imagine you'd really see a difference then (since I've done it, albeit not controlled or intentional...)

Nice work.

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Thanks! One variable at a time, my friends, one variable at a time