confused about autolysis

I read about the dangers of letting your beer sit in the primary too long on the yeast cake risking the effects on autolysis.. My question is, if thats a "real thing" then why dont the same thing happen to beers that are bottle carbonated and conditioned monthes, sometimes years...Arent they also sitting on a yeast cake of sorts?

Autolysis is a real thing but generally only a problem to large scale brewery's. as it generally only occurs from the pressure/weight of many gallons of beer pressing down on the yeast. Not really a Homebrew scale problem.

I've just never experienced it or know anyone personally that has. I Typically leave my Ales in the primary for at least three weeks, and my Lagers are usually left in the primary for at least a month. My Marzens are left in the Lagering vessel for at least six months, and although they are trasnfered off the primary's yeast cake they still have yeast in them. I believe it can happen though....... just not very likely for a home brewer.

The problem is when yeast cells are exposed to too much pressure/weight/time/etc that it doesn't like and causing a mass dieoff.

Yeast is really pretty darn tough stuff, it withstands being freeze dried, rehydrated, then attenuated and put into a bottle, pressurized and chilled for months or years on end.

If you leave your beer or wine too long on the lees, you might notice a distinctly yeasty flavor, but its pretty difficult to cause autolysis under normal conditions. I've always siphoned off to a 2ndary if my yeast cake reaches 1" thick though, as i'm not that brave

wyoast said:

I read about the dangers of letting your beer sit in the primary too long on the yeast cake risking the effects on autolysis.. My question is, if thats a "real thing" then why dont the same thing happen to beers that are bottle carbonated and conditioned monthes, sometimes years...Arent they also sitting on a yeast cake of sorts?

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What you were reading is outdated/over exagerated information. We really DON'T concern ourselves with either. People have left their beers in primary for a year with no "autolysis issues;" that whole rack the beer off the yeast hysteria has been pretty munch debunked, INCLUDING by John Palmer who sparked the whole panic to begin with.

Read this, and you'll see that even John Palmer, who caused the whole autolysis panic among new brewers like you has retracted his views on it....

Nowadays even many instructions, in BYO magazine, and even some kits suggest a long primary as opposed to using a secondary. So it's pretty obviously that they're not buying that bogeyman anymore either.

I suggest you read THIS thread, it's become the "uber discussion" on this topic thread.

To Secondary or Not? John Palmer and Jamil Zainasheff Weigh In .


Autolysis is not the inevitable end of healthy yeast. It is the unnatural end that is a product of yeast health...like peritinitus or even cancer in us....it is an abberation....UNHEALTHY AND STRESSED yeast autolyse... but rarely do we have unhealthy yeast these days, most of the yeast we pitch is fresh...and unless we are making a huge beer, even underpitching will not NECESSARILY produce stressed out yeast. Or stressed out yeast that will automatically autlolyse....

Most yeast that folks call dead, is actually dormant. Like most of what's in the bottom of the fermenter when fermentation is complete. Or the bottle when bottle conditioning is complete.

And the yeast is indeed dead, a lot of it is canibalized by the living yeast. And the rest, if the yeast was healthy to begin with, is just dead....think of it as natural causes, it's not necessarily spilling it's "intestinal" goop into our beer.

As Palmer and Jamil have said it is a RARE occurance these days that yeast actually dies anymore, let alone actually autolyses. It just goes dormant when the job is done and waits for the next round of sugar (much like when we pitch on top of the old yeast cake- which even some commercial brewers do for multiple generations.) The cells rarely rupture and die off.

It's not like 30 years ago (when most of those opinions that you espouse about autolysis originated from) when our hobby was still illegal, and there wasn't a lot of FRESH yeast available to us. The yeast used in hobby brewing was usually in cake form, which came from Germany and England in hot cargo ships and may have sat on a store shelf for a long time....or the brewer just used bread yeast.

Palmer even said this in the broadcast I quote from above-

So the whole health and vitality of yeast was different back then compared to now. Back then it made sense. You had weaker yeast that had finished fermentation that were more susceptible to autolysis and breaking down. Now that is not the case. The bar of homebrewing has risen to where we are able to make beer that has the same robustness as professional beer. We've gotten our techniques and understanding of what makes a good fermentation up to that level, so you don't need to transfer the beer off the yeast to avoid autolysis like we used to recommend.

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Yeast in the 21st century is much healthier to begin with, and is less prone to have issues like their cells autolysing....just like our own health tends to be better these days.

Many of us leave our beers a MINIMUM of 1 month before racking or bottling, folks have left their beers in primary for a year or more with no issues. This is not something these days that most brewers (except noobs just stumbling onto Palmer's free book,) worry about.

And yes, people have consumed bottle conditioned beers that were over 100 years old and the word "autolysis" never entered the equation.....

Don't be "confused" or even concerned about the boogeyman...very few of us are.

Wow thanks Revy! I actually caught a thread about this floatin around here shortly after I posted this question... Very informative stuff here though.