View Full Version : Warm conditioning

scott isham
11-02-2004, 09:24 AM
I have read somewhere that some British breweries warm condition thier beers as opposed to cold conditioning the beers. I was wondering, short of helping the yeast to drop out of suspension, what other benefits does cold conditioning provide after primary fermentation is complete. I am starting to wonder if instead of crashing my beers to 32 degrees for two weeks I could just allow them to condition at fermentation temp.


11-02-2004, 11:31 AM
With cold conditioning, in addition to yeast dropping out of suspension, you'll also get proteins (chill haze) forming and dropping out of suspension, too. Condition warm and chill for serving, and instant haze. And the cold inhibits bacteria growth...

Cheers, Tim

dick murton
11-02-2004, 12:04 PM
The warm conditioning is primarily a chance for the diacetyl produced by the yeast during fermentation to be mopped up and converted to less flavoursome compounds. (Other compounds are produced, but this is the most widely monitored compound).Ale yeast tends to produce more diacetyl than lager yeasts, especially at ale fermentation temperatures. The level produced varies with yeast strain, fermentation temperature, wort composition (to a limited extent) yeast concentration etc etc.

The diacetyl rest reduces the level so that the beer doesn't have a butterscotch character, or at least, an overpowering one. Some beers do have a detectable level remaining, and this is a key characteristic of that beer.

After warm maturation, the beer is generally cold matured, not necessarily for two weeks, but whatever time is considered appropriate to remove chill haze, normally not less than 48 hours.

If you crash cool immediately the final desired PG is achieved, you may need to cold mature for an extended period purely to remove the diacetyl etc.

If you cold mature for a long time there are other more subtle changes, but can you afford to refrigerate for months ?