Autolysis shouldn't be feared.

[zoebisch01]

Ok.

This is a 'biggie' but to my knowledge I don't know anyone who has ever suffered the effects of Autolysis enough so that it ruins the beer or is even noticeable for that matter. After talking with my friend Phil, he made a very good point. Autolysis is happening. Like it or not, your Yeast will die. And like it or not, they will impart the flavors resulting from their dead bodies, fatty acids and lipids. What many people don't have a handle on is why they never see the effects of this in their beer. There may be some people out there, but I only recall reading one thread where the poster was describing "Soy Sauce" flavor, which is undoubtedly Autolyzed Yeast.

What sets most people into the 'safe' zone often turns out from common practice. That being racking your beer off the trub before it is too old. Here is where it gets complicated. That time depends on a myriad of factors, which are mainly temperature, recipe, Yeast strain and the particular grain bill and hop additions. The latter two being related to the masking ability of the ingredients. There is no 'hard and fast rule' that will allow one to figure out how long beer can sit on the trub. But, there is a balance between the necessary time to fully ferment a batch and a 'safe' time to pull a batch off the trub. Most of the primary fermentation in Ales is finished under 4 days. There is a safety margin here, which I am sure there are people out there playing around. Again, a 7 or 10 day rule on primary is really a habitual working model for many folks, myself included.

I almost always pull beer off the primary at around 10 days and have never noticed anything to do with Autolysis in terms of it making beer taste bad. In my bottle conditioned Ales, there is always a layer of Yeast sediment and again, no off flavors. I know people that have gotten away with leaving a batch on primary for an extended period of time. I did this once, it was on there for almost 3 weeks, fortunately to no ill effect. This suggests that only large amounts of Yeast at warmer temperatures induce the negative effect.

So what have been your experiences? It would be an interesting endeavor over time to collect data from different time lengths on primary and try to see if we get any trends in the data. I can say from experience that an average of 10 days primary with an Ale has never given me noticeable off flavors from Autolysis. I don't brew many Lagers, but due to the decreased fermentation temperature the safe zone probably extends a little, but it should be kept in mind that many Lagers tend to be more delicate recipes (or naked as I like to call them) that won't hide off flavors.

[Evan!]

I brewed 10 gallons of german pils on 3/15 and it's been lagering in primary ever since (~4.5 weeks since end of fermentation). Yes, it is a "naked" recipe---not much more than pils, hallertau and WLP838. No off flavors at all so far. I figure I'll keg half of it soon, and rack the other half to a 5 gallon bright tank for extended lagering. I'm getting a little anxious, as I've never left a lager on primary this long, but the dudes in my homebrew club said they do it to no ill effect...and you're more likely to eff it up with oxidation with all those rackings. Dunno how much truth there is to that, but, in any case, I've seen no problems after 4 and a half weeks on the cake post-fermentation.

I do have to wonder, though...when you re-use a cake a bunch of times, wouldn't you still expect to have this problem? Yet, I have several beers that I made with the same Thames Valley cake (Gloaming first, then a Mild, then a Pale Ale, then a Blonde), and none of them have these problems either.

[zoebisch01]

I do have to wonder, though...when you re-use a cake a bunch of times, wouldn't you still expect to have this problem? Yet, I have several beers that I made with the same Thames Valley cake (Gloaming first, then a Mild, then a Pale Ale, then a Blonde), and none of them have these problems either.

That's another really good point. I am wondering now, as I have done this as well with no troubles related to Autolysis off flavors, that if there isn't some other Yeast function going on which can reabsorb the Lipids and such. In fact, Phil just mentioned that Yeast can indeed handle Lipids, he is currently experimenting with frying hops for utilization. Damn, I bet you that is what happens in some cases. I wonder if when there is a resurgence of new Yeast growth, (or even just activity for that matter) even in 'small' numbers that reabsorbs a bunch of that stuff that gives those particular off flavors. I always rack quietly onto an established cake so as not to start the whole growth process again.

This is good, and I think having us hash out our experiences can help give us insight.

[Ó Flannagáin]

I've left beers in primary for almost 2 months in over 70F temp with no "soy sauce" like off flavors. In fact, some of them came out amazingly clean. I have a gumballhead I just put into the keg last week that was there for probably 5 or 6 weeks in primary. The last 2 weeks or so it got up to mid 70's in the house. The beer tastes great.

[Evan!]

That's another really good point. I am wondering now, as I have done this as well with no troubles related to Autolysis off flavors, that if there isn't some other Yeast function going on which can reabsorb the Lipids and such. In fact, Phil just mentioned that Yeast can indeed handle Lipids, he is currently experimenting with frying hops for utilization. Damn, I bet you that is what happens in some cases. I wonder if when there is a resurgence of new Yeast growth, (or even just activity for that matter) even in 'small' numbers that reabsorbs a bunch of that stuff that gives those particular off flavors. I always rack quietly onto an established cake so as not to start the whole growth process again.

This is good, and I think having us hash out our experiences can help give us insight.

Great point...exactly what I was willing to assume.

Oh, and now I have this hilarious image in my head of you tiptoeing around and whispering while you rack "quietly"...

[MrMarbleHead]

When I brewed my 999 Flanders Red back in July I had every intention of pulling it off of the yeast cake after about a month. But due to my lazyness and curiosity, it has been there since last July (going on 9 months). The last sample I pulled off of it was back in Nov, so 5 months on the yeast cake at 65ish deg, and I noticed no off flavors at all, it was somewhat bland in the flavor dept, huge in the aroma though, IIRC. And granted this beer has a ton of funk going on with the brett and the bugs, but I noticed nothing out of the ordinary.

As a matter of fact, that sounds like a good project for tonight, I need to rack that beer over and get some oak on it. I will let you know what I come up with.

[blacklab]

I often get busy and don't have time to rack out of primary for over a month or so. I've gone three months in the past. I ferment in my basement where it's 60-65 year round.
There's never been an appreciable difference, in my experience.

I wonder if you need to get up into the 80's for an extended period to see the effect.

[Lerxst]

I've often seen the flavor of autolysis described as soapy to meaty, broth/soy sauce and rubbery. I'd imagine that production would be influenced by time, temp, yeast health and perhaps strain.

I had one batch that because a little bit soapy over time in the bottle...it was fairly well hopped so I initially wrote it off from that but the more I thought about the development of the flavor, the more I wondered about the possibility of autolysis. So, what about bottle conditioning? I've read in the past that one of the flavor contributions of bottle conditioning is due to some autolysis but look at some of the beers you did when you were a noob and had wicked sediment in your bottles...you'd think that would contrubte some major action.

I've run a number of batches into 4 weeks in the primary with no noticible autolysis effect...granted, this is usually done at mid to low 60s.

...another thing you always have to consider when we talk about our subjective observations is how different our palets are and many of us, myself included, may not be able to detect some of these more subtle defects.

[zoebisch01]

Great point...exactly what I was willing to assume.

Oh, and now I have this hilarious image in my head of you tiptoeing around and whispering while you rack "quietly"...

Add some Fluffy animal caricature slippers and a robe and your good to go.

[zoebisch01]

...another thing you always have to consider when we talk about our subjective observations is how different our palets are and many of us, myself included, may not be able to detect some of these more subtle defects.

Ya know, that's something I always wonder about as well. I am a firm believer in 'good enough' meaning there is a threshold it would be easy for my anal side to get a hold of and run with to the point that everything is 'perfect', but I am not sure most people (possibly myself included) would be able to pick up on. The good enough point is one thing I try to balance my beer around because I always have several plates spinning and have only so much time and effort to put into beer.

This is another reason why this discussion is intriguing. Where does the peak of the peak of the gaussian distribution lie for most homebrewers. I'd say judges would shift right, and the common beer drinking would shift left. The 'good enough' point would be the peak, and you could probably apply this to other things...diacetyl, etc...but I digress.