Home Brewer Irrational Fear Of Autolysis

[Wolfy]

It's very common on these forums (and elsewhere) for home brewers to offer advice to suggest that beer should be racked off the yeast-cake as soon as possible - if the beer is to be stored, lagered or not bottled for even a few weeks, the fear of autolysis seems to be an all pervasive consideration.

While it is likely true that (From: How to Brew):

At a minimum, a beer that has experienced autolysis will have a burnt rubber taste and smell and will probably be undrinkable. At worst it will be unapproachable.

Obviously producing a beer that bad is something to avoid at all costs, however, how many home brewers have ever done that?

The 'Yeast' book (at least the way I interpret the information) goes to lengths to suggest that many home brewers remove their beer from the yeast too quickly and as a result the beer quality suffers.
In addition, even the scary sounding quote above is directly followed by this:

As a final note on this subject, I should mention that by brewing with healthy yeast in a well-prepared wort, many experienced brewers, myself included, have been able to leave a beer in the primary fermenter for several months without any evidence of autolysis.

To test my hypothesis that most home brewers' fear of autolysis is irrational, I brewed a beer (dark & hoppy AltBier) on 10th August last year (so it will be 1 year old in 3 weeks), it has been sitting in the primary fermentor, unrefrigerated (through the Melbourne spring, summer and autumn) since fermenting/lagering.
Upon smelling/tasting the fermentor sample today, it has none of the burnt rubber smell/taste described in that article nor is it undrinkable or unapproachable.
(Nor does the beer taste that good out of the fermemtor, but it was the flavours usually associated with autolysis I was considering.)

I'm not a beer-judge and I know many others have more refined beer-tasting-palate than myself.
However, I am still curious to know if any home brewers have made a beer that suffered from autolysis and if so what did you do to cause it to happen?

Edit: I don't mean to suggest that autolysis - as a process does not happen. Rather that - when making and drinking beer - it's not something that should be as irrationally feared as it seems to be by many.

 

[Nick JD]

When I keep yeast samples of trub that is only about 10 days old (in a 300ml PET bottle; ~20% trub) and leave them in the fridge (~6C) for 2 weeks, they are significantly vegemitey.

Would the yeast not have got vegemitey if left in the primary? Or would the taste been too diluted by the 20L above it to be noticable?

Autolysis is real; people's perception of it varies.

 

[Bizier]

I think most autolysis I have encountered has been from home brewers bottling with tons of stressed primary yeast making it into the final package. Professional brewers usually filter and then re-innoculate with a small amount of very viable yeast, and often one with a longer life, such as a lager strain.

There is also a very common commercial brewing schedule with a designated warm maturation period for yeast in solution to uptake green beer compounds before going through to chilling tanks for clarification.

I have left my primary yeast cake in a fermenter last summer in Perth (40C daily) for 2 weeks or so THAT was defninitely autolysed upon cleanup. I think you would have to underpitch with old yeast and ferment at 30C for 2 months to get kind of stuff in your beer though.

I have had professional brewers say to me that they are after a very slight nutty autolysed character in big aged beers though, and that will be a determinant of when the beer is released, though these are beers with only the slightest amount of residual yeast present.

 

[Wolfy]

When I keep yeast samples of trub that is only about 10 days old (in a 300ml PET bottle; ~20% trub) and leave them in the fridge (~6C) for 2 weeks, they are significantly vegemitey.

Would the yeast not have got vegemitey if left in the primary? Or would the taste been too diluted by the 20L above it to be noticable?

Autolysis is real; people's perception of it varies.

I didn't mean to say it's not real, or that it does not ever happen.
Rather, that - in a batch of standard home brew beer - it's not something that is as prevalent as many people make out.

However, I think it's fair to expect concentrated yeast-samples to be yeasty & vegemitey.

I have left my primary yeast cake in a fermenter last summer in Perth (40C daily) for 2 weeks or so THAT was defninitely autolysed upon cleanup. I think you would have to underpitch with old yeast and ferment at 30C for 2 months to get kind of stuff in your beer though.

I've noticed the same.
But edited the first post to make it clear that it's not the process or even consequences of autolysis that I doubt, but rather the irrational fear that many home brewers seem to have, and that autolysis is not something that will happen quickly or easily (if most sensible brewing procedures are followed).

 

[Greg.L]

I've never had autolysis problems, I don't think they are a major concern. I keep my cider on lees for 6 months sometimes without problems, I know cider isn't beer, but still. There are advantages to leaving your brew on the lees - yeast cells are good at soaking up excess oxygen, so help protect against oxidation. I don't see how you could get autolysis in less than 2 months, just my opinion.

 

[Nick JD]

However, I think it's fair to expect concentrated yeast-samples to be yeasty & vegemitey.

For sure. I reckon it's also probably a factor in the "bottled vs kegged" taste difference, especially if the bottles are getting on. Not saying it's always a bad thing, just that in a very subtle lager some yeastiness character can be a little annoying.

I've never tasted "burnt rubber" but the subtle umami of a touch of autolysis on the back of the tongue is real in old, bland bottle conditioned beers.

I think autolysis is a lot like diacetyl - often confused and in different quantities has different flavours.

Easy test would be to filter off some of a beer into a keg, and leave the rest on primary for 6 months, and then keg it ... taste the two back to back, ten bucks says the one on the yeast for 6 months is a bit umami.

 

[newguy]

In the very early stages, I pick up autolysis as flintstones vitamins and in later stages as rotten fruit. The really nasty burnt rubber only manifests in extreme cases. While relatively rare, I can remember at least one example from every competition I've judged.

The only time I've had it develop was in a keg that was left in extreme heat with a not insignificant amount of yeast left in it. I've left beer in the primary for 6+ weeks more times than I can count with no ill effects. I agree that it's a bit of a brewing "momily".

 

[Nick JD]

I pick up autolysis as flintstones vitamins...

Like Fred, or more like Barney?

 

[pbrosnan]

It's very common on these forums (and elsewhere) for home brewers to offer advice to suggest that beer

If you stop right there you can add in any number of pieces of advice that are mostly nonsense. Autolysis is unlikely to be a significant cause of off flavours in beer. Just as "scorched wort", while greatly feared, is rarely, if ever, actually reported. I think that most of these mythical fears are felt most by people who are new to brewing. Once you've done thirty or so brews you start to realise that so long as you have your basic processes worked out there's not a lot that can go wrong.

 

[MHB]

Im going to take exception to the term Irrational in the heading Autolysis is real and is something we should consider when we are brewing.
As a retailer I get a lot of beer brought in for me to taste, samples fall largely into two categories FIGJAM and WTFWW, the Fk Im good or at least very happy with the beer are usually a pleasure to taste. The WTF went wrong - well at best they can be educational. Taste beer on a regular (daily) basis for a decade and you will I promise run into most of the faults among them Autolysis and yes burnt rubber is a very good descriptor.

From observation I am going to say that the biggest cause of Autolysis is yeast abuse, particularly heat pads, (I wont even sell them) heating a beer from the bottom where the oldest most likely to Autolyse yeast is, is irrational.

In a well made wort, with healthy yeast and leaving the wort in contact with the yeast cake for a reasonable amount of time under reasonable conditions then no you wouldnt expect any problems, we could have a very long conversation about the term reasonable but Im sure you get the point.

A new K&K brewer, who got talked into a heat pad, pitches 5-6g of yeast in to an oxygen deficient wort and brews at 25oC or hotter has very good reason to be concerned.
Mark

Agree that Burnt Rubber is the extreme end point as a flavour fault, it doesnt appear instantly and there are other detectable symptoms of Autolysis that appear earlier, none of them make the beer taste better so are best avoided.
M

 

[Wolfy]

In a well made wort, with healthy yeast and leaving the wort in contact with the yeast cake for a reasonable amount of time under reasonable conditions then no you wouldnt expect any problems, we could have a very long conversation about the term reasonable but Im sure you get the point.

I get the point and think we are in agreement.
The irrational fear I talk about is related to many home brewers suggesting that beer has to be racked (out of primary) as soon as possible, or that autolysis is going to be a major problem. But that in 'reasonable' conditions the beer can often usually be left on the yeast for a 'reasonable' period of time without any issues at all, and possibly improving rather than detracting from the resulting product.

 

[kario]

in 'reasonable' conditions the beer can often usually be left on the yeast for a 'reasonable' period of time without any issues at all, and possibly improving rather than detracting from the resulting product.

+1 from experience:

When I was 'very' new to brewing (still consider myself an infant), I went through a 'rack off to secondary' stage......I ended up with a couple of batches that tasted like green apples.....after racking to secondary at 7 days. It dissipated completely from one batch after about 6 mths, but still lingers in the other.

I've also had a very intriguing pvc/vinyl taste from a hastily racked beer, but I think that's another kettle of fish.

Have since stopped racking, leave on primary for (on avg) 2 weeks (I know it should be longer, but I i seem to always be running low on beer, makes me impatient), then cold crash for a few days and bottle.

 

[hoppy2B]

I've been experimenting with green malt.
Earlier this year I made an all wheat which I put through the blender and then into the mash. It looked like beer before mashing as it was all frothy. Basically I aerated the fuuuuuun out of it.
Used my whole harvest of wet POR as a late addition on it, about 800gm. Put another 100gm wet POR late pick into the FV a couple of weeks later and left the whole thing for at least a couple of months before bottling.
Anywho, long story short, I was pretty disgusted with the results. After investing my whole POR harvest the thing came out tasting like burnt rubber.
Only procrastination and laziness stopped me from emptying all the bottles I suppose. I normally wash each bottle as I drink it. Didn't feel like washing all the bottles at once.
A month or 2 later now and the rubber taste has dissipated greatly and is almost all gone.
I don't know what the hell is going on. :lol:
I'm thinking perhaps that's why POR gets such a bad rap as an aroma hop. I did a brew with wet frozen Cluster at the about the same time and that is still improving now 3 or 4 months down the track also.
So perhaps flavours that are put down to autolysis are sometimes something else and wet hop brews need longer to go through stages of maturation.

 

[newguy]

Like Fred, or more like Barney?

More like Wilma actually.

 

[MHB]

I've been experimenting with green malt.
Earlier this year I made an all wheat which I put through the blender and then into the mash. It looked like beer before mashing as it was all frothy. Basically I aerated the fuuuuuun out of it.
Used my whole harvest of wet POR as a late addition on it, about 800gm. Put another 100gm wet POR late pick into the FV a couple of weeks later and left the whole thing for at least a couple of months before bottling.
Anywho, long story short, I was pretty disgusted with the results. After investing my whole POR harvest the thing came out tasting like burnt rubber.
Only procrastination and laziness stopped me from emptying all the bottles I suppose. I normally wash each bottle as I drink it. Didn't feel like washing all the bottles at once.
A month or 2 later now and the rubber taste has dissipated greatly and is almost all gone.
I don't know what the hell is going on. :lol:
I'm thinking perhaps that's why POR gets such a bad rap as an aroma hop. I did a brew with wet frozen Cluster at the about the same time and that is still improving now 3 or 4 months down the track also.
So perhaps flavours that are put down to autolysis are sometimes something else and wet hop brews need longer to go through stages of maturation.

I suspect the trouble might be the green malt.
Malt needs to be kilned (died) and then rested for at least a week (preferably longer if less consistent) before it is used for brewing.
I feel a bit the same about hops; a lot happens during drying, I dont believe I have ever tasted a wet hoped beer that was worth the effort. A bit late you can get away with too much and the beer is a mystery bag of off flavours.
Mark

 

[popmedium]

Man, this is very timely and I'm glad the topic got started. As a new brewer, it's really hard to know what to do. Some books advocate racking heavily and there is a lot of jungo on the internet saying you should do it also. But then you go and read a bunch of forums and all the experienced home brewers will tell you that you don't need to rack.

Currently I have a few lagers down and I've been losing sleep over whether I should have racked for the lagering period. In total both beers will be on the primary yeast cake for 6 weeks, which people seem to think is reasonable.

From what I've been able to deduce, there are a couple of good reasons you might want to rack, but autolyis isn't really at the top of that list. Good reasons being:

- DRY HOPPING. Folks have said you get a much better hop aroma if the beer is off the primary yeast cake
- YEAST HARVESTING. Yeast will be healthier and more viable if you grab it after primary. Alternatively grab you can top crop.
- CLEARER BEER: I'll cope a punch for this one, but when I was racking I did notice that my finished beers were clearer. It's true that this can be achieved with a more refined process overall, but it is a cheats way of getting a slightly clearer beer.

Again, love that this is being talked about.

 

[RobboMC]

and could I add - TOO BUSY TO WASH 50 BOTTLES.

Sometimes my schedule makes it difficult to get a finished brew into bottles,
so instead of letting it sit for 2 more weeks I choose to rack and leave it safely in a cube.

No chorus of 'get a keg set up' please.

 

[Margarine]

Racking, and the reasons for racking, are greatly misunderstood on this forum (and other forums, for that matter).

The main issue is the lazy-internet-inspired-truncation of the term 'secondary fermentation'.

There is a big difference between racking post terminal gravity (eg, for the purpose of clarification), and racking for secondary fermentation, which is, in essence, racking prior to terminal gravity. Racking for secondary fermentation means that you are doing a two stage fermentation process. The beer is racked prior to final gravity being achieved. The purpose of this is to remove the beer from the spent yeast, to expel (at least some) saturated CO2, to transfer viable yeast with the green beer to the new vessel, to ensure a minor uptake of O2 to rejuvinate the yeast, and, being held at, or slightly below, fermentation temperature, resulting in a full and complete attenuation, including the conversion of residual volatiles produced by the yeast during primary fermentation....

Short, (not entirely correct, but adequate for illustration purposes,) example is that racking should occur 1 (one) life cycle of the yeast prior to expected terminal gravity for optimal effect of secondary fermentation. In real terms, somewhere in the region of 2-4 gravity points.

I rack my (good) beers for secondary fermentation, prior to terminal gravity; If, through inattentiveness (or if it's a 'standard', or, alternatively speaking, 'I can't be buggered') beer, I fail to rack prior to terminal gravity, I don't bother racking at all. Too late, missed the boat. (note; I am referring to beers with minimal conditioning time: I don't do lagers, and rarely do beers large enough to require extended conditioning).

In relation to clearer beer: yes, and no, in relation to racking. I find that beers that have been racked for secondary fermentation, or, beers that have been racked post-FG, for the purpose of clarification, may clear faster than beers that have not been racked at any stage. But this is not to say that unracked beers are unable to achieve full brightness; unracked beers can, and will, drop bright, providing that it is handled correctly; which is to say, that it is handled with a mindset that takes into account the full process of the brewing of said beer.


Ahhhh, I'm as wordy as ever, it would appear.

 

[Thirsty Boy]

all true

but still mainly something that need concern brewers in a commercial situation where the conditions at the bottom of large fermenters are much more aggressive than those you'll find in a homebrew fermenter.

Co2 levels, pressures, etc much lower and DO almost certainly higher in the HB setting than in a commercial one, so for the most part, the quite good reasons you might rack, or crop yeast from, fermenters in a commercial situation are far less pressing for the homebrewer.

Brewing is a pretty natural process, i think in most situations, you should interfere with that natural process when and where you have a good reason to do so - & while there are reasons to rack from primary fermenter, the reasons for doing so are IMO (as per the OP) generally overstated for homebrewers.

If you can state a reason to rack and you can outline the potential detriments in doing so, your strategy for mitigating them and how the benfits outweigh the residual detriment. Then of course you should transfer to "secondary". But if you dont have the skill/experience/knowledge to run through that mental weighing up process, then I reckon its a step that falls into the "better left alone" category.

 

[manticle]

Racking, and the reasons for racking, are greatly misunderstood on this forum (and other forums, for that matter).

The main issue is the lazy-internet-inspired-truncation of the term 'secondary fermentation'.

There is a big difference between racking post terminal gravity (eg, for the purpose of clarification), and racking for secondary fermentation, which is, in essence, racking prior to terminal gravity.


Ahhhh, I'm as wordy as ever, it would appear.

When I used to rack, I did it entirely for the latter purpose. No trouble attenuating out and no noticeable apples, toffee, butter etc.

However I did eventually stop that as part of my normal process and haven't noticed drastically negative effects. What you've outlined though has always been my understanding of proper secondary fermentation. It requires the beer to be still fermenting, not at FG (and carbonation in the bottle to me, while technically a fermentation was never really what I thought of as a secondary fermentation - bottle conditioning or carbonation, not SF).