Autolysis

[pcmfisher]

I know of the slight risk of autolysis caused by leaving your beer on the yeast cake for extended times, but does the same thing happen to bottle conditioned beer that is stored for a long time?

Isn't it a similar thing - you have beer sitting on top of a mini yeast cake in the bottle.

If so would it have the same detrimental affect and how long would it take to happen?

 

[Pete2501]

No it wouldn't and doesn't have the same effect.

Autolysis is when the yeast runs out of food/nutrients and starts looking for them in dead yeast cells. There just aren't enough cells in a bottled beer for this to occur.

It is a similar situation but the amount of yeast and food in a bottle compared to that in a carboy just doesn't rack up (pun intended ) so to speak.

 

[zebba]

I've read reviews for Russian Imperial Stouts that refer to a slight autolysis flavour becoming evident after aging, although in those examples it was listed as good thing adding complexity, not as a prominant flavour.

 

[floppinab]

Not sure if thats 100% right Pete, just pulled the below off the web somewhere.

"Yeast autolysis or self-lysis is the breaking open or rupturing of the yeast cell and the transfer (leaking out) of undesirable substances and off-flavours to the beer."

It occurs when yeast becomes old and weak, are exposed to stressors (v. high alc, high salt), are shocked (rapid cooling or warming).

Healthy yeast cells can metabolise some of the compounds leaked out of autolysing yeast but generally if conditions are prevalent that yeast are autolysing, those conditions impact all the yeast, meaning there aren't generally too many healthy yeast around to metabolise the nasties coming out of the autolysing yeast.

To answer the OP's question, yes it can particularly if conditions occur to accelerate (generally high alc., temperature and age). That said there generally isn't enough yeast in the bottle to severly effect the flavour of the beers and (if stored well) you are talking years for any tastable impact.
I've picked a bit up in some Old Ales, Coopers Vintage > 6 or 7 years but not to the extent where it severly impacts that flavour of the beer.

 

[dent]

I've had it in bottle conditioned lagers stored at 'room temp' over the whole of summertime.. probably got over 35 degrees pretty often for extended periods.

 

[Pete2501]

My point is with so little yeast the chances of this happening are slim. As you say you have to be a ******* to your beer or leave it for ages so this can occur. :icon_cheers:

On the other hand if you were aging a beer it would be kept in a controlled environment with little fluctuations in temperature which is likely the most common cause of autolysis for home brewers. Isn't that right Dent?

 

[Pete2501]

If you're really interested in Autolysis.

I found this article from 1985. Autolytic Release of Mannoproteins from Cell Walls of Saccharomyces Cerevisiae.

http://mic.sgmjournals.org/cgi/reprint/131/11/2925.pdf

By the way, cheers for the topic. I love all facets of beer. I even enjoyed finding this article.

Ps. Saccharomyces Cerevisiae... think US05.

 

[Nick JD]

If you beer still holds a head it probably doesn't have any of the byproducts of the breakdown of yeast cells.

 

[mondestrunken]

Rather than start a new thread here, I'm hitchhiking on this one.

I'm currently cleaning the homebrewery and came across a couple of unopened brews from 2009-2010. Of course I had a little sample, and one in particular smells and tastes like Vitamin B tablets - almost just like a Berocca, which I'm diagnosing as autolysis.

This was back in the good old days of packet yeast, no starter, no aeration, ~30 degrees fermentation (come on it was summer!), etc.

Nowadays I routinely leave beer in primary for 2-3 weeks, and don't get autolysis aromas and flavours.

I suggest that autolysis is more likely to occur from crappy yeast handling practices and fermentation, rather than time spent on yeast. Any thoughts?

 

[DJ_L3ThAL]

Rather than start a new thread here, I'm hitchhiking on this one.

I'm currently cleaning the homebrewery and came across a couple of unopened brews from 2009-2010. Of course I had a little sample, and one in particular smells and tastes like Vitamin B tablets - almost just like a Berocca, which I'm diagnosing as autolysis.

This was back in the good old days of packet yeast, no starter, no aeration, ~30 degrees fermentation (come on it was summer!), etc.

Nowadays I routinely leave beer in primary for 2-3 weeks, and don't get autolysis aromas and flavours.

I suggest that autolysis is more likely to occur from crappy yeast handling practices and fermentation, rather than time spent on yeast. Any thoughts?

VITAMIN B!!!! I've been trying to categorise an off flavour from some brews a work mate gave me which were many years old, they all had the exact same flavour even across different styles. I have tried one of my oldest bottles (from about 2010) which had a similar flavour, but bit more dull as the beer was not as old as my work mates ones! I can't comment on whether it is autolysis or not but it's definitely something funky that is happening to beer that's just become far too aged, there is clearly a shelf life for home brewed beer.