When to Pitch 34/70

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Yacov327

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Started a lager today. It's crazy hot here. Was able to chill the wort to 79f then put it in the fridge. It's been there for a few hours now.

How long is it acceptable to wait to pitch yeast? Do I need to pitch it now or can it wait till the morning for the beer to cool down?
 

Bassman2003

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It is best to pitch immediately but you can wait for the batch to cool down. The risk is oxidation will be increased if the batch sits there without the yeast to consume the O2. If you have something to float on the surface of the wort (like a cake pan etc...) it will slow down the O2 ingress. Another angle is to transfer the beer after it has had time to settle out all of the trub etc... So you are getting a 2nd benefit for letting it sit. I have done this by putting the wort into a bucket with a spigot, letting that chill and then gravity transferring to my fermenter. The wort is crystal clear with the method.
 

pvtpublic

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Pitch at 45, then let it rise to 50. If you pitch it warm and let it cool, you could run the risk of the yeast producing esters and other off flavors for lagers, as well as possibly putting the yeast to sleep. Estery and under attenuated lager is a sad lager
 

pvtpublic

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It is best to pitch immediately but you can wait for the batch to cool down. The risk is oxidation will be increased if the batch sits there without the yeast to consume the O2. If you have something to float on the surface of the wort (like a cake pan etc...) it will slow down the O2 ingress. Another angle is to transfer the beer after it has had time to settle out all of the trub etc... So you are getting a 2nd benefit for letting it sit. I have done this by putting the wort into a bucket with a spigot, letting that chill and then gravity transferring to my fermenter. The wort is crystal clear with the method.
Part of the yeasts' metabolism is to use oxygen to create energy, just as we do, but they also have an alternate way to metabolize without oxygen; fermentation. Yeast will consume all the oxygen in the wort before it has a chance to oxidize. When it uses the o2, it allows for cell growth and helps strengthen the cell walls. Fermentation won't happen until the o2 has been used up. I've had lager wort sit in my fridge for a week (still in my boil kettle) before I pitched, due to my busy schedule and I've never had an issue with oxidation. However if it still concerns you, I understand. If you have a keg system, just purge your carboy with the co2 and then fill it. If not, don't sweat it, you'll have a good beer anyway.
 

McMullan

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Yeast respire - like us - when the environment contains O2 and about <1% glucose. Otherwise fermentation is much more efficient than aerobic respiration, metabolically speaking, for yeast cells in liquid media. Under controlled experimental conditions only about 1/3 of O2 mopped up by yeast cells gets used to replenish lipid membranes. The rest seems to get metabolised as a means to cope with oxidative stress. Interestingly, dry yeast (ADY) have no need to replenish their lipid membranes, which were replenished before or during the commercial drying process. But they still mop up O2, once sufficiently active. Wort is going to contain barley and hop derived reactive oxygen species in solution (i.e., biochemically risky). There's a reason why we practice drying as a method to preserve biomass. A healthy yeast innoculation helps minimise the risks of oxidation by ROS in wort. For the OP's situation I'd pitch once below 30°C (86°F). It's going to take at least a day or two before they start doing much. The desired fermentation temperature is going to be reached long before then. No point in delaying things.
 

fbold1

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W34-70 is one of my favorites, German lager from Weihenstephan. very active, leave plenty of headspace. I have pitched warm (80 F) with great results.
 

monkeymath

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As you can tell from the responses, this topic is subject to some controversy. Generally speaking, the main benefits of pitching early are
- oxygen absorption
- quick pH drop (limits activity by other organisms)

The second point may be debated by folks saying "I've never had an infection from pitching late", but I think the issue is a bit more subtle. Brewing at home, all our beer is destined to be "infected" to some degree. Airborne contaminants always make it into the wort. Under the "right" conditions, their growth will be limited by hops, scarcity of oxygen (for some microbes at least), low pH and, once fermentation is well underway, ethanol. Getting healthy yeast in there is a key step here. Even if your beer won't taste obviously infected, I think there's a good chance your beer may not come out quite as clean as it could.

Now, the issue with pitching too warm is mostly the formation of esters, which happens primarily during the early stages of fermentation - so pitching warm and then cooling down is problematic. What's more, the cooling will impose stress on the yeast, which can lead to a number of problems down the line: increased production of fermentation byproducts including esters and fusel alcohols, sluggish fermentation, ...

So, yeah, we are in a bit of a pickle here! When I was living in Hamburg, there was a guy at the local homebrew club who was famous for brewing the best lagers. When I approached him about it, he said he'd pitch a small amount (like a tenth of the starter volume or so) of yeast at elevated temperature and then wait until fully cooled before pitching the rest.
I think in terms of oxygen absorption, even a small amount of yeast works (compare the "yeast oxygen scavenging method" used by some people to deaerate their strike water). The pH drop, on the other hand... Not quite as much, probably, it'd be interesting to get some measurements here.
As far as ester production goes, I was sceptical: aren't we essentially doing a massive underpitch at an elevated temperature? Mister Lager's take on it was that the small amount of yeast wasn't able to get anything going within the relatively short timespan. I can't really judge whether that line of reasoning is accurate, but his Franconian lagers convinced me that he must be doing things right.
 

McMullan

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Now, the issue with pitching too warm is mostly the formation of esters, which happens primarily during the early stages of fermentation - so pitching warm and then cooling down is problematic.
Dry yeast manufacturers recommend rehydrating yeast at something like 34°C. This was confirmed years ago by scientific research. If you then pitch into FV wort at lager fermentation temperature you're going to promote more stress on the yeast than if you had pitched below 30°C then cooled to the desired fermentation temperature. Note an FV full of wort cools relatively slowly with minimal shock to the yeast cells. It's actually sudden temperature change that promotes a shock response. Note too that ester formation is associated with yeast metabolism throughout the fermentation process, not just the early stages. Again, the wort is going to reach the desired fermentation temperature rather steadily - without promoting yeast stress - long before the yeast start doing much metabolically.
 

monkeymath

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Dry yeast manufacturers recommend rehydrating yeast at something like 34°C. This was confirmed years ago by scientific research. If you then pitch into FV wort at lager fermentation temperature you're going to promote more stress on the yeast than if you had pitched below 30°C then cooled to the desired fermentation temperature.

Which is also why that is not how you rehydrate yeast: you repeatedly add small amounts of cool water or wort to slowly bring the yeast down to the wort's temperature.
 

Bassman2003

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I should have prefaced my oxygen comments to mainly apply if you created a low oxygen wort and want to protect it. Otherwise, I agree, not much oxidation risk as the wort is already oxidized from the brew day.

The post chilling method is a great way to brew lager in hot climates. So I would go for it.
 

JohnDBrewer

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You can wait 12-hrs no issue to get the wort down to a good pitching temp. I pitch below 50 and let it raise to 50-52. Make sure you have a big enough amount of yeast to pitch and you should have no issues. More o2 in the chilled wort will only help fermentation before you pitch.
 

McMullan

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Well researched? Scott Janish? I see. Guys, FFS, if you're pitching dry yeast, you don't have to factor in pitching temperature as such. This is getting funny. I think I tossed Janish's 'New IPA' on the wood burner over the winter, tbh. What a load of bollocks that was. It ended well in my wood burner 🤘
 

FloppyKnockers

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Started a lager today. It's crazy hot here. Was able to chill the wort to 79f then put it in the fridge. It's been there for a few hours now.

How long is it acceptable to wait to pitch yeast? Do I need to pitch it now or can it wait till the morning for the beer to cool down?
Samzies here... I got my wort down to 78° then put it in the fermenter (58°) overnight, then pitched the next morning. Have to do that during the Texas summers - Ales and lagers alike. No problems at all.
 

rootAndBoom

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Well researched? Scott Janish? I see. Guys, FFS, if you're pitching dry yeast, you don't have to factor in pitching temperature as such. This is getting funny. I think I tossed Janish's 'New IPA' on the wood burner over the winter, tbh. What a load of bollocks that was. It ended well in my wood burner 🤘
Am I missing something about Janish, or did you just not like the book?
 

monkeymath

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Well researched? Scott Janish? I see. Guys, FFS, if you're pitching dry yeast, you don't have to factor in pitching temperature as such. This is getting funny. I think I tossed Janish's 'New IPA' on the wood burner over the winter, tbh. What a load of bollocks that was. It ended well in my wood burner 🤘

Is there any beer writer or blogger that you actually tolerate? I think Janish is at least the first one you did not downright call a con-artist...
 

McMullan

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Am I missing something about Janish, or did you just not like the book?
No, I've read some of his blog posts and his book, `New IPA'. Clearly, one of us has missed something. Clue: I don't believe it's me who's missed anything 😉
Is there any beer writer or blogger that you actually tolerate? I think Janish is at least the first one you did not downright call a con-artist...
You're free to add that label yourself, really. It fits and it's not my responsibility to keep pointing these things out, FFS.
 

rootAndBoom

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No, I've read some of his blog posts and his book, `New IPA'. Clearly, one of us has missed something. Clue: I don't believe it's me who's missed anything 😉

You're free to add that label yourself, really. It fits and it's not my responsibility to keep pointing these things out, FFS.
I try to follow good research as well as listen to the opinions of brewers more experienced than I am. The post I linked to includes 32 citations, which I think most of us would agree constitutes good research. Can you enlighten me about what exactly it is that I've missed? With citations, if you're able? ;)
 

lumpher

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I've waited as much as 24 hours to pitch yeast. Many of us who do no-chill wait many hours. I just yeasted an ale 2 days ago I brewed 3 days ago.
 

McMullan

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I try to follow good research as well as listen to the opinions of brewers more experienced than I am. The post I linked to includes 32 citations, which I think most of us would agree constitutes good research. Can you enlighten me about what exactly it is that I've missed? With citations, if you're able? ;)
List as many citations as you like. If you can't interpret them for what they are, bit of a moot point really, isn't it? Another clueless blogger blagging it generally. How do you justify that? Are you able to? 😉
 
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