Pitch temp--why go so low?

Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum

Help Support Homebrew Talk - Beer, Wine, Mead, & Cider Brewing Discussion Forum:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.
Joined
Sep 2, 2012
Messages
1,370
Reaction score
472
Location
Woodiville
I'm new with only 3 batches under my belt... and just one of them in bottles. I'm trying to understand some conflicting advice I have received on how to pitch yeast.

My LHBS recipes all say, "... cool the wort to 80F and pitch the yeast. Be sure to follow the yeast manufacturer's directions."

But around here, it is commonly said that you should pitch the yeast at or under the fermentation temperature.

Obviously, you do not want the wort to be too hot or the yeast are in peril. And equally obviously, each strain has an ideal temperature range, or schedule.

But is it really necessary to cool the wort all the way to fermentation temperature? It doesn't *seem* to be necessary because the wort will cool from 80F to fermentation temperature within a couple of hours, for a 5 gallon batch anyway.

And during this cooling time, the yeast are adapting to their new home, reproducing, using up the oxygen, and not yet fermenting. The wort will have hit target temperature well before we enter the anaerobic domain. At least, that's how I reason it out. But the weight of opinion is apparently stacked against me.

Are there other byproducts of aerobic metabolism that impact the flavor of the beer?

Do the yeast use up the oxygen quickly enough that they could be fermenting in a warm wort?

Is there another factor that I am overlooking, making a cool wort an ideal home for the yeast?

Cooling the wort further is not a great hardship, but it does mean more time babysitting the immersion chiller... those last 10-20 degrees will take a while. So if I can get equal end results with a pitch just under 80F, that's what I would prefer to do.

I am curious if anyone has done a split batch test with differing pitch strategies, and evaluated the tastes of the final products.
 
You do want to cool to as close to ferm temp bc of the off flavors you will produce as well as because you want to make sure you will cool to that low to ferment at avoid the esters
 
It's all a matter of scale. If fermenting hot for two weeks creates lots of bad flavor - fermenting hot for a few hours creates a little bit of bad flavor.

Basically it's an optimization thing. Optimally, you want to condition your yeast for the exact conditions they'll be doing their work in. This would mean creating a starter of similar strength and at a similar temperature to the fermentation they'll be doing. This mean that when you introduce the yeast to your wort they're ready to rock.

So, under optimal conditions pitching fermentation temp yeast into ferm temp wort is what you're looking for.

In general, however, you're correct, the product you'll get when pitching at 80 and allowing to cool to ferm temps will be fine, maybe sub-optimal, but still possibly very good.
 
I think the LHBS/yeast supplier instructions are intended more for mitigating worry than they are for brewing great beer. If you pitch warm, you'll (often) observe a quicker visible start to fermentation, which is probably what most new brewers are looking for. Also, if you're not making a starter (which most new brewers aren't), then a warmer pitch temperature should decrease the lag time that would otherwise result from underpitching.
 
I think the LHBS/yeast supplier instructions are intended more for mitigating worry than they are for brewing great beer. If you pitch warm, you'll (often) observe a quicker visible start to fermentation, which is probably what most new brewers are looking for. Also, if you're not making a starter (which most new brewers aren't), then a warmer pitch temperature should decrease the lag time that would otherwise result from underpitching.

That makes sense.

I certainly haven't used a starter yet, and my 3 batches with liquid White Labs yeast all started bubbling within 12-24 hours. I cooled the wort to 80F, and by the time it was in the bucked and aerated it was a couple degrees cooler.

The argument that you are conditioning the yeast to the environment that they will be working in sounds extremely reasonable, but there is no way to know if it pans out without testing. If it did work that way, it means that yeast starters should be grown at fermentation temperature, too.

Interesting stuff, thanks everyone.
 
yeast don't like to be cooled/chilled. they can drop out and it can take a while for them to realize that it ain't getting any warmer (again), so best get to work. you will minimize your lag time (time between pitching and active fermentation) by pitching slightly cooler yeast into stable, final fermentation temp wort.

although it can take a while to see krausen and bubbles, the yeast may well be working away in there. don't assume that because there aren't visible signs that nothing is happening. and:

> And during this cooling time, the yeast are adapting to their new home,
> reproducing, using up the oxygen, and not yet fermenting.


yeah, and they won't being any of that very quickly if they're being chilled.

so ideally, you cool the work down to 66*F (of whatever your desired fermentation temp is), and pitch yeast that is, say, 60*F. i do this by pulling my starter out of the fridge one hour or less before pitching, instead of half a day. the yeast will warm up quickly to 68*F, think it's a frikken warm day in july, and get down to work.

yeast are funny. warm them up to 75*F and pitch them into 68*, they complain and some will drop out while others will go on strike for a while. chill that same yeast down to 60 and pitch into 68, and they party like they're on a beach.

you may have seen that for some types of ale, particularly belgians, call for ramping up of temperature during the course of fermentation. no one ever calls for cooling the beer during fermentation. one instance when you do want the temp of the beer drop is during cold-crashing, and the idea there is to get yeast to drop out. good for after fermentation, not good during.
 
If you're interested, Yeast: The Practical Guide to Beer Fermentation by Zainasheff and White goes into great detail on exactly these kinds of issues.

I was just reading about this in the Yeast book actually, at least from my reading of it they seemed to say that it's acceptable to pitch the yeast at the warmer temps during the lag phase to help the yeast get started, and that it really shouldn't affect off flavors too much.

But ultimately I think pitching at or close to the prime fermentation temp is the best practice.
 
Pitching at the low end or even slightly below the low end of the temp range makes it easier to keep the temp in check. As the yeast takes off the temp wants to increase and it is easier to control if it is in the low end of the range.

If you start warm and the yeast takes off fast, the temps could rise above where you want it to be before you can get it down. It is much easier to let it rise slowly than having to try to cool it too fast.
 
So....

The reason it is advisable to pitch at or, preferably below is all about creating a controlled growth phase of the yeast. The growing of yeast is all about yeast health which is why pitch rate and pitch temp and aeration are so important.

If you pitch the proper cell cell count into a properly aerated and slightly cold wort the yeast will grow at a controlled rate for optimum cell count growth. Basically what you are trying to do is create the best workforce needed to provide the best fermentation for your beer.

If you don't create the optimum environment for the yeast to do their best work all kinds of problems can arise, some minor, some major.

BTW, I highly recommend the book!
 
I tend to pitch lagers at the warm end and let it cool slowly. If I pitch on a cake, I always hit the low end.
 
The long and short of it is the yeast are the workhorses of beer. Everything you do is to create a happy environment and (flavorful )food for them to consume. The happier you make them the happier they will make you.
 
I tend to pitch lagers at the warm end and let it cool slowly. If I pitch on a cake, I always hit the low end.

I don't do lagers so I cannot talk about that, but I hear that they take off slowly.

I do brew a lot of Belgians and that is a recipe for disaster. I did a brew and pitched it toward the high end of the temp range. The yeast took off and stayed hot for a long time before my fermentation chamber could cool it down. Total Fusel bomb. Also Belgian yeasts do not like to be cooled down after they start or you risk a stuck fermentation.

I guess it gets down to understanding the yeast you use and how it work best for you.
 
The reason it is advisable to pitch at or, preferably below is all about creating a controlled growth phase of the yeast. The growing of yeast is all about yeast health which is why pitch rate and pitch temp and aeration are so important.

As a pro brewer friend of mine has said - his job isn't about grain, water and hops - it's about yeast ranching.

A majority of the things we do while brewing are about creating conditions that the yeast like. Yeast doesn't like temperature fluctuations or light. Pitching yeast into ferm temp wort is the best option. If you have temp control on your fermentation theoretically after pitching the yeast should be in a constant temperature - which make them happy.
 
Seems like everyone is saying the same thing here for the most part. And I would concur as well. I did 4 brews this past weekend and was only able to cool the wort down from the boiling tempt o about 78/80 degrees. My starters were conditioned in ferm chamber the morning of at 68 degrees. I pitched at the 78/80 degree temp w/ the 68 degree starters and saw yeast activity in 4-6 hours and the following day (yesterday) saw crazy blowoff happening where as I had to take out the airlock and replace w/ blow off tubes for two of the brews. The other two got close to blow off but managed ot stay within the carboy.
So to be honest this thread has shed some interesting light on on the process of how yeast works in the proof that I've seen with my 4 batches the past three days.
 
Back
Top