Lager fermentation temp interrupted by vacation

[SaisonMan]

Just curious: What would be the result of shutting off temperature control on a lager after 4 weeks and then having it sit in the fermenter at room temperature for two weeks? This shouldn't be an issue for me because I live in a cold climate and can lower the thermostat in my house to 54 while I'm gone. But what if lived somewhere warm? What if the temp went up to 68 or so for a few weeks? Any negative effects? And, yes, this question assumes a keg isn't available for a transfer.

 

[VikeMan]

The higher the temperature at which beer is stored, the faster the staling reactions, i.e. the shorter the shelf life. You can estimate that these reactions happen 2 to 3 times faster for each 10C increase in temperature. Here's a slide from an old presentation with an example:

 

[SaisonMan]

That's cool. Thanks. It backs up one of life's golden rules: drink faster.

 

[RM-MN]

The higher the temperature at which beer is stored, the faster the staling reactions, i.e. the shorter the shelf life. You can estimate that these reactions happen 2 to 3 times faster for each 10C increase in temperature. Here's a slide from an old presentation with an example:

View attachment 845419

I must really like stale beer because a lot of mine sit at 68-74 from the time I bottle them until I finally get to drink them. I've drunk a stout that was 2 years in the bottle and it was better than the one I drank at 1 year.

That chart might apply to lagers, especially the commercially available ones.

 

[AlexKay]

The "assumed baseline" is essentially a made-up number.

 

[VikeMan]

The "assumed baseline" is essentially a made-up number.

Of course. It's an illustration of how temperature changes things relative to the assumed baseline. Pick any baseline you want and do the math, but the phenomenon is the same.

 

[VikeMan]

I must really like stale beer because a lot of mine sit at 68-74 from the time I bottle them until I finally get to drink them. I've drunk a stout that was 2 years in the bottle and it was better than the one I drank at 1 year.

That chart might apply to lagers, especially the commercially available ones.

It (the phenomenon of faster reactions at higher temps) applies to chemistry in general. So it's not just staling reactions. There were also other things happening in your stout, some of them positive from a taste perspective. Some big, dark beers get a "net benefit" from aging. But the staling reactions are still happening, accelerated by higher temps, as are the "good" ones. The problem for brewers/drinkers is that most beer styles do not benefit from extended (or temperature accelerated) aging.

 

[AlexKay]

To circle back to the OP’s question, leaving the beer in the fermenter at warmer temperatures will likely not be too bad. Live yeast have enzymes that metabolize some of the undesirable oxidation products. (This is one reason why bottle conditioned beers often age better.) But not to extremes; too much time and you’ve got dead yeast instead of live, and your beer starts to taste like soy sauce or something equally unpleasant.