Autolysis: fact or fiction

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Have you experienced yeast autolysis?

  • No, never had it happen to me

  • Yes, with 2 to 3 weeks in the primary

  • Yes, with 4 - 5 weeks in the primary

  • Yes, but with 6 weeks or more in the primary

  • WTF is autolysis???


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FlyGuy

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OK, yes yeast autolysis is actually a potential concern (not fiction). But is it a substantial concern? I have been gradually moving away from secondaries and leaving my beer longer and longer in the primary. With up to 6 weeks in the primary, I still haven't perceived anything resembling autolysis. The more I investigate the topic, the more it seems that autolysis is awfully hard to produce.

So, the question is 'Have you experienced autolysis, and if so, how long did you leave your beer in the primary to achieve it?' Comments on the type of beer, yeast, fermentation conditions, etc. would be helpful if you have experienced it. If it was a one-time or rare event, perhaps that could be mentioned too. Thanks.
 
I've had it when I failed to clean out a fermenter. Took about two months, in the summer.
 
Never had a problem. The longest I've left a beer in primary was 31 days, and it was fine. Of course, it was 1.090 OG, so that may have helped. :drunk:
 
I leave 1.090+ beers in primary for 6-8 weeks on occasion and never have any problems with it.

Wayne
Bugeater Brewing Company
 
My last ale (a Highland Gaelic clone) sat in primary 63 days at around 65-70F with no problems. Only one data point, though.
 
I just racked a beer to secondary, 1.072 og brewed on 1/21 (today is 6/24). I don't taste anything bad. As far as I'm concerned it's a warm sweet stout, as it should be.
 
My doppelbock sat in the primary at least 7 months and no autolysis. My barleywine sat in primary 5 months, no problems.

Now, I left a carboy out that had been racked, but still had the yeast cake in it for a few days in the hot sun. Oh yea, problems.
 
99% of beers that I make sit in the primary for 4 weeks then another week in the fridge cold crashing and getting gelatin. I've had several go 6,7, or 8 weeks in primary before getting kegged. I've never noticed any autolysis in my beers. In fact, I had a APA that went 8 weeks get a score of 40 in a homebrew comp. None of the judges noticed any off flavors in that beer.

I do tend to ferment on the cold side for ales, usually low to mid 60's so maybe that helps to keep autolysis from occurring. I tend to think it may be more of a problem for commercial brewers who generally pitch much higher volumes of yeast than homebrewers and deal with the weight of much larger batches.
 
I don't understand autolysis. Some think it is a problem in the primary, but yeast is ok in the bottle for 6-12 months with no problem.

What is the difference between yeast in the primary and yeast in the bottle for 6-12 months.
 
I just kegged two 5 gallon batches (summer ale & amber ale). Both of these batches sat in the primary for four months. Not a hint of autolysis. Autolysis is the homebrewing boogyman.
 
IWhat is the difference between yeast in the primary and yeast in the bottle for 6-12 months.

Volume of yeast compared to volume of beer? The yeast in a bottle is usually a pretty small amount (barring a hefe), for converting a slight amount of sugar to CO2. The yeast in primary is a huge amount.

Exposure to oxygen? Atmospheric pressure?


I don't think yeast autolysis is an issue, but there are some differences in a bottle and a primary.
 
As a scientist who occasionally works with yeast (more often bacteria). I can guarantee you that autolysis is occuring in our brewing. As soon as vigourous fermentation stops, there are going to be yeast dying. The big myth is what this does to our beer. Normal biological autolysis DOES NOT produce the nasty flavors we've all heard about. It will give some light bready/yeasty notes, and apparently some fruity esters (see post 57 of Orfy's autolysis thread).

Then there is the autolysis that one gets from totally abusing a beer (too hot, infection, late oxygen exposure). These will give the nasty flavors.

Handled properly, the contribution of normal biological autolysis to a brew sitting in a fermentor for a long time will not be that great. Abuse it, and you'll be in for a shock.
 
apparently i'm one of the few who have had an issue with autolysis. hefe in primary for 3wks that went very bad. it actually turned me off to hefe's for about a yr. temps in the high 60's low 70's wlp 380.
 
There is a difference between autolysis and decaying yeast cells. In clean beers (e.g., light lagers), decaying yeast cells can produce off-flavors above taste threshold. These might not be noticeable in flavorful ales.

So, it depends on the beer and the temperature at which it is stored after primary fermentation is complete. For my lagers, I like to get them off the yeast soon after primary fermentation finishes. For ales, I wait 3 weeks and wouldn't be too concerned at 4. Beyond that, and at room temp, I'd start to get concerned... not necessarily for autolysis, but for decaying yeast.
 
There is a difference between autolysis and decaying yeast cells.

+1. We need to get the brewers to follow the terminology used in microbiology. Vintners appear to be doing better at this. Autolysis is the normal self-lysis that occurs as part of the life cycle of a yeast cell. I like the term decay, as that implies the activity of another agent (ie infection). The nasty off-flavors might start as normal autolysis, but it takes something more than that to get the true nastiness.

Think of a bonfire pile just sitting there. By itself, it is just going to sit there and do no harm, heck it'll even provide some shelter for some critters and can be a good thing. Now, add a little spark and it will turn into something quite different!
 
I've concluded, like pjj2ba said that autolysis does happen. I have not had any off flavors from it. I have also not had any yeast decay off flavors by leaving beer or cider in a carboy for 3+ months.
 
I've only had it in a mead that sat way, way, way too long on the lees in primary.

You couldn't even swallow your sip...it was bad.
 
I have a Saison that I forgot about, in the primary, sitting in my basement since last October. I'm kegging it up this weekend, so I'll report back. :eek:
 
Another concern of extended yeast contact besides nasty
flavors is the yeast's release if a protein degrading enzyme. This enzyme, called proteinase A, is known to affect head retention negatively.

I like to get my beers off the yeast or a least chilled for clarification as soon as they are done fermenting. But I also tend to skip the secondary for most ales.

Kai
 
I made a cranberry cider that sat in the primary on the yeast for 9 months @ ~77 degrees. Kegged a few weeks ago and tastes awesome.
 
I did a raspberry wit that I ended up leaving in primary for 51 days, and it was fine, for the most part. It got a tiny infection at the top, but when I transferred it to secondary, I was able to leave that garbage behind, and never had any other problems during secondary or after bottling.

I also left a massive imperial stout in primary for 50 days, and it is one of the best beers I've ever done. Had a Christmas ale in primary for 49 days last year, no problems.
 
I think we've just about concluded that if you respect your beer you can forego secondary for most standard ales and leave for a month or two in the fermenter without fear of autolysis or decaying yeast causing problems.

RDWHAHB.
 
Hey there! Yeah, I rarely use secondary now unless it's a gigantic beer or if I'm doing something special like adding fruit.
 
I'm not going to say autolysis doesn't happen, I just think it needs certain conditions.

I recently helped a neighbor bottle a beer that sat in the primary fermenter for nine months. The beer, while overaged and not at its peak, was plenty drinkable.

The yeast was S-05, and it had been stored in a 65-70F basement. Based on those results, I'm not going to worry about autolysis over 4 to 6 week ferment.
 
I've concluded, like pjj2ba said that autolysis does happen. I have not had any off flavors from it. I have also not had any yeast decay off flavors by leaving beer or cider in a carboy for 3+ months.

Oh, I think it's scientifically demonstrable that autolysis does HAPPEN. The question here isn't its existence, but is it anything that's likely to be an issue to the homebrewer within any reasonable primary duration? Reasonable time in primary? I say 4 weeks is reasonable. My longest primary has been three weeks (a primary-only), with no ill effects. If it won't happen in a month (and there's no documented case in this thread or anywhere else I've read) = not a problem.

We can then put this one to bed.....except that no homebrewing boogeyman EVER goes to bed. Not hot-side æration, not the presumptive superior crush of a $200 mill over a $25 one, etc.
 
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