Autolysis Myth - BUSTED

Okay, I've been WAY out of the brewing scene ever since my wife had our first child on Superbowl Sunday. The last batch I brewed was a couple weeks before he was born, and I FINALLY today am transferring it to a keg. The original gravity was 1.066. Today, I checked it, and it's 1.012. 7% ABV. It's a Belgian Porter.

I wanted to post this because everyone worries about nasty flavors from dying yeast, but I'm here to say that fear is extremely overblown. I left this thing completed untended in primary for 139 days, and it tastes awesome. While 1.066 OG is fairly strong, it's nothing that crazy, and when I checked the gravity a few months ago, it was already down to 1.013, so it's done very little additional fermentation in the meantime.

Anyway, point is, you can leave a beer safely in primary for months without worrying about dead yeast. Just thought people would be interested in hearing about my experience, as it was a good one. And now I finally get keg beer again. The next step is to figure out how to brew beer while holding a four month old baby. :rockin:

Wow thats a long time to wait, Awesome result.

I never make anything complicated enough to warrant such a long ferment, although I did hear that Samichlaus beer ferments for 10 months, if that doesnt cause problems I dont know what will.

edit:

Grats on the Baby as well as the beer

Haha, the long ferment time was definitely not planned! SWMBO thought the batch was doomed for sure.

Karma, seeing as it shares a date with the newest member of your family make sure you put one aside for him/her for another 17 and a half years

Congrats on the baby and thanks for the tip. When mine comes (October), I'm praying I don't have to take a long break.

Torchiest said:

The next step is to figure out how to brew beer while holding a four month old baby. :rockin:

Click to expand...

Luckily, babies have cribs, and beer mugs have handles...guess which one you can set down! Just kidding. Congrats the baby and the brew, enjoy the ride!

I can also verify that yeast is a hardy animal. I saved most of the refrigerated yeast cake from a Coopers IPA brewed about a month ago. Washed it, pitched it into some leftover wort, and it is absolutely taking off.
Hardly any dead yeast, and now I got to figure out a brew to use it on.

Torchiest said:

The next step is to figure out how to brew beer while holding a four month old baby. :rockin:

Click to expand...

That is what Baby Bjorn's are for.

This should be a sticky!

I have a similar story. I brewed an Octane IPA from a Midwest kit and then hurt my back. I wasn't able to lift, move or anything for a couple months. My beer sat in the fermenter for 16-weeks on the yeast and it also, was fantastic. Granted, I don't think my taste is refined enough to be able to taste the effects of yeast autolysis, but the beer was really good. I'm not as worried about it these days after my little "experiment."

2-0turbo said:

Granted, I don't think my taste is refined enough to be able to taste the effects of yeast autolysis, but the beer was really good.

Click to expand...

Trust me, from what I've heard, you don't need refined anything to detect autolysis. It smells like a dead animal stuffed in a tire, I believe.

Torchiest said:

Trust me, from what I've heard, you don't need refined anything to detect autolysis. It smells like a dead animal stuffed in a tire, I believe.

Click to expand...

Ever had Marmite, Vegemite or Champagne?

The myth is that autolysis leads to strong nasty flavors. To get the yeast to make those kind of flavors you really need to abuse it. Things like extra oxygen after fermentation is complete, high temperatures, and probably also requires some kind of infection.

Autolysis is a normal part of the yeast life cycle. Once a yeast culture has reached stationary phase (vigorous fermentation has ceased), some of the yeast will start to autolyze. In the lab, this is absolutely occuring so I don't think this is somehow miraculously not occurring in beer. The myth is that it creates strong nasty flavors.

I think it was an unfortunate coincidence and there was something else going on in a bad batch of beer and someone said "Oh, it must be autolysis", and the terminology stuck. I'm sure that was going on, but there were other mitigating factors as well.

I congratulate the OP on taking good care of his yeast!

Good post. My main thrust was that the dangers are way over-hyped, and a typical batch won't encounter any problems even if left alone for multiple months. In fact, my experience is in line with the great John Palmer:

10.3 Autolysis

If anything, I think there's more harm in racking the beer out of primary too early. My first IPA was 1.06x and I bottled it after two weeks. It took a few more weeks for the off-flavors to clear up.

Patience is a virtue in this hobby.

Torchiest said:

Good post. My main thrust was that the dangers are way over-hyped, and a typical batch won't encounter any problems even if left alone for multiple months. In fact, my experience is in line with the great John Palmer:

10.3 Autolysis

Click to expand...

Actually, that section by Palmer is what I have a big problem with.

He made the assumption, that of all the microbes floating around in the air it was a yeast that settled into the open pot of rice glue. There are plenty of microbes out there that can do fermentation, and some natural yeast that are pretty funky too. Actually any organism breaking down sugars is going to release CO2 and cause bubbles in a liquid. This was not wort with hops in it to help limit what would grow in it. This is like leaving a pot of Mac and cheese on the stove for a week and then seeing it growing and smelling nasty. Yup, must be yeast autolysis.

I was just reading an article in Science News about human fungal infections (not common) and they say, "A 2005 study found that about a million spores are nestled in your pillow alone." And that is just fungus. There are probably even more bacteria, which will happily do fermentation too.

My impression has always been that autolysis is more an issue to long term bottle conditioning rather than bulk fermentation.

pjj2ba said:

Actually, that section by Palmer is what I have a big problem with.

Click to expand...

Yea that section wrongfully scares a lot of people. He actually admitted that the information is out of date, and corrected it in the later editions of the book. The web version is still the 1st version though, and unfortunately tons of people still use it w/o realizing what has changed.

We discuss this here, but I'm not surprised by the results in the OP. Great to see actual results though.

Granted, I don't think my taste is refined enough to be able to taste the effects of yeast autolysis,

Click to expand...

Believe me, one does not need refined taste buds or a good sense of smell in this case. I've created autolyse once, left a yeast cake on the back porch for two months, in the summer. Open cesspool would be a polite way to describe it.

BillyBroas said:

Yea that section wrongfully scares a lot of people. He actually admitted that the information is out of date, and corrected it in the later editions of the book. The web version is still the 1st version though, and unfortunately tons of people still use it w/o realizing what has changed.

We discuss this here, but I'm not surprised by the results in the OP. Great to see actual results though.

Click to expand...

The other myth that needs serious busting is "Never, ever, leave your beer in the primary more than 14 days. Otherwise, you will get oxygen contamination and your beer will be ruined." It seems that Revvy has been leaving beer in the primary fermenter for a month, and winning awards with ruined beer. :cross:

Hear, hear! The fears of autolysis really are overblown (in my experience with meads, at least), and I have to agree with Starderup's point about leaving things in primary.

Torchiest said:

Okay, I've been WAY out of the brewing scene ever since my wife had our first child on Superbowl Sunday. The last batch I brewed was a couple weeks before he was born, and I FINALLY today am transferring it to a keg. The original gravity was 1.066. Today, I checked it, and it's 1.012. 7% ABV. It's a Belgian Porter.

I wanted to post this because everyone worries about nasty flavors from dying yeast, but I'm here to say that fear is extremely overblown. I left this thing completed untended in primary for 139 days, and it tastes awesome. While 1.066 OG is fairly strong, it's nothing that crazy, and when I checked the gravity a few months ago, it was already down to 1.013, so it's done very little additional fermentation in the meantime.

Anyway, point is, you can leave a beer safely in primary for months without worrying about dead yeast. Just thought people would be interested in hearing about my experience, as it was a good one. And now I finally get keg beer again. The next step is to figure out how to brew beer while holding a four month old baby. :rockin:

Click to expand...

Good Stuff!!!! I had a feeling that was overblown...Anyways, I know how them little munchkins can take up pretty much all of your free time for a long long long time. Have fun brewing away.

I'm sorry, I have to de-bust the autolysis myth.
Autolysis exists.
This comes from a competition scoresheet of my German Pils (rude translation):

... the beer is generaly very correct, except for strong autolysis, both in aroma and flavour (baked patato, burned milk)....

The beer was 4 weeks on pimary in 50F. Yeast : Bohemian lager slurry, 5th harvest, the slurry was washed and very fresh (1 day after harvest)

That doesn't really prove anything, though. It's completely possible that the judge was detecting some other off-flavor, which she has been taught to identify as autolysis. (Did she inspect your beer under a microscope and find an excess of ruptured yeast cells?)

Similarly, the OP's unintentional experiment doesn't really prove anything either, except that an absurdly long primary does not necessarily result in bad beer. With the lack of any sort of rigorous experimentation, all we can assert with certainty is this: Most, but not all, people who have attempted long primaries have been happy with the results.

The could mean any number of things: a) long primaries only sometimes cause autolysis; b) autolysis is caused by some other factor that is exacerbated by long primaries; c) long primaries don't cause autolysis, but they sometimes cause some other problem that is falsely labeled autolysis; d) long primaries have nothing to do with it, but some completely unrelated problems are sometimes falsely labeled autolysis; e) long primaries cause autolysis, but depending on the style and/or taster it may not always be particularly detectable in the flavor; f) long primaries cause autolysis only under certain conditions; etc. We really can't tell between those alternatives with the data we have.

Like I say: All that can be stated with certainty is that many, but not all, people who have tried long primaries are happy with the results. Until more rigorous data is available, that means each brewer will have to make their own decision.

Edit: Oh, and the one thing the OP's experiment proves is that this phenomenon whereby many (but not all) people who attempt long primaries are happy with the results, that appears to extend to really absurdly long primaries, like the OP's 20 weeks.

4 weeks is nowhere near long enough for that to happen. You do have to remember that judges are not perfect. I routinely leave my beers in the primary for 4-6 weeks. It does nothing but let the yeast finish and clean up, and also clears the beer.
This has been my consistent experience, and have never had those flavors at all. YMMV.

jsweet said:

Like I say: All that can be stated with certainty is that many, but not all, people who have tried long primaries are happy with the results. Until more rigorous data is available, that means each brewer will have to make their own decision.

Click to expand...

Good points. I'm perfectly happy with long primaries but the geek in me would also like to see some experiments that show the cell death rate over time in the fermentor.

Piotr said:

The beer was 4 weeks on pimary in 50F. Yeast : Bohemian lager slurry, 5th harvest, the slurry was washed and very fresh (1 day after harvest)

Click to expand...

Unless the yeast were really stressed out or there was some sort of fermentation issue, 4 weeks isn't nearly enough time for autolysis to occur.

Piotr said:

I'm sorry, I have to de-bust the autolysis myth.
Autolysis exists.
This comes from a competition scoresheet of my German Pils (rude translation):

... the beer is generaly very correct, except for strong autolysis, both in aroma and flavour (baked patato, burned milk)....

The beer was 4 weeks on pimary in 50F. Yeast : Bohemian lager slurry, 5th harvest, the slurry was washed and very fresh (1 day after harvest)

Click to expand...

I have hard time believing that sorry, since I just did experiment for myself - fermented (2 weeks) and lagered (3 weeks) all in same vessel, in carboy, on yeast (wyeast 2206). It is Vienna Lager and I cannot detect any off-flavours

piotr said:

Yeast : Bohemian lager slurry, 5th harvest

Click to expand...

I think this is the key point no one is noticed. Were you pitching onto an old yeast cake repeatedly? After 5 batches on the same cake, and then fermented for 4 weeks, this could be true...

HokieBrewer said:

I think this is the key point no one is noticed. Were you pitching onto an old yeast cake repeatedly? After 5 batches on the same cake, and then fermented for 4 weeks, this could be true...

Click to expand...

Since he washed it it should be fine.

Assuming he washed it correctly. Either way 6th gen yeast is different than the initial fermentation.

HokieBrewer said:

Assuming he washed it correctly. Either way 6th gen yeast is different than the initial fermentation.

Click to expand...

I am completely in agreement. Every time you touch yeast, you are risking contamination. I'm all for reusing or washing yeast to save money, but not when it might cost you $25 to save $3.

I have done the parallel culturing, and that is an awesome way to maximize your investment. The benefit of it is that all your resultant yeast is second generation at the most. IMHO, it is really 1st, but some people count that initial culture as 1st.

BillyBroas said:

Good points. I'm perfectly happy with long primaries but the geek in me would also like to see some experiments that show the cell death rate over time in the fermentor.

Click to expand...

Get a pH meter. The pH will drop during fermentation, be stable for a while, and then start to rise. When it rises, yeast are lysing. This is temperature and yeast cake depth dependent but in reasonable conditions and subject to the accuracy of a homebrew grade meter this does take on the order of weeks (weeks not months) to occur in hombrew.

In commercial cylindroconical tanks with a yeast depth of a couple of feet it can happen in days.

Autolysis isn't a myth, the idea that autolysis is evidenced by fecal or rubber aromas is. For lack of a better term, autolysis contributes umami (free glutamate). This can range from nutty and bready flavors you wouldn't notice in beer (but are noticeable and desired in sparkling white wine and mead) to brothy or meaty flavors that are notable in aged stout and barleywine or in Marmite/Vegemite.

remilard said:

Autolysis isn't a myth, the idea that autolysis is evidenced by fecal or rubber aromas is. For lack of a better term, autolysis contributes umami (free glutamate). This can range from nutty and bready flavors you wouldn't notice in beer (but are noticeable and desired in sparkling white wine and mead) to brothy or meaty flavors that are notable in aged stout and barleywine or in Marmite/Vegemite.

Click to expand...

Correct! It is only an off-flavor if you don't like it. Many folks are drinking beers that are affected by autolysis and are loving them! Heck, I might even go as far as to say a large percentage of homebrewers like the flavors

Palmer's book has perpetuated the nasty flavor myth. He had a nasty stinky pot of homemade rice glue that went bad and exclaimed, "Ahah, this must be yeast autolysis!" even though he had no evidence that this was the case (no added yeast btw). So now people don't detect these nasty flavors in their beers so they say, yup, no autolysis, when in fact all it means is that they didn't have a nasty infection like in that forgotten rice glue pot

What about a long primary fermentation in a plastic bucket?
Any problems with leaviung it in an Ale Pale or some similar plastic food garde bucket (sold by a reputable brew supply store) for 4-6 weeks?

I have three different five-gallon batches of homebrew that need kegging, ranging from probably three to five months of sitting on yeastcake. I'll see if I can get motivated to keg some beer today (seems to fit the theme of the thread) and we will see how it is coming along.



Leaving your stuff in an ale pail for 4-6 weeks should be fine.

Correct! It is only an off-flavor if you don't like it. Many folks are drinking beers that are affected by autolysis and are loving them! Heck, I might even go as far as to say a large percentage of homebrewers like the flavors

Click to expand...

I agree. Its just like how most brewers don't think they have an oxidation problem, when they have just become used to the flavors and don't realize that they do. Or the post you see where some guy pitched a six month old yeast cake and it happens to ferment, so the person proclaims that there is no problem with using six month old yeast cakes.

Am I saying that you can't leave the beer on the yeast for longer than 4 weeks? Absolutely not. Some people are content with their process and it works for them. That's fine, just don't run around and say that its the only way to do it and that there is no yeast dying in there.

remilard said:

Get a pH meter. The pH will drop during fermentation, be stable for a while, and then start to rise. When it rises, yeast are lysing. This is temperature and yeast cake depth dependent but in reasonable conditions and subject to the accuracy of a homebrew grade meter this does take on the order of weeks (weeks not months) to occur in hombrew.

Click to expand...

Good idea. I was planning to buy a pH meter soon anyways.

Torchiest said:

Trust me, from what I've heard, you don't need refined anything to detect autolysis. It smells like a dead animal stuffed in a tire, I believe.

Click to expand...

...the rubber cement smell is unmistakable.

Trust me, that is VERY accurate. I rehydrated US-05 in a sanitized growler for 2-weeks after thinking I would need it to help something ferment out, but ended up leaving it in growler, only rehydrated with water....

needless to say opening that thing was a HORRIBLE mistake indoors. tossed that bad boy outside and bleached the growler and all is well. however, i Have never had any yeast on top of some form of wort/beer go bad like that did. The particles/nutrients in the wort help the yeast go dormant and not autolyze.