Subject: Re: DMS and counter flow chillers.
Date: 1992-06-29 16:43:59 GMT
Russ Gelinas writes:
> I've got some question that pertain to chillers, hopping, and all
>this sort of stuff we've been talking about. Isn't it a good idea to
>allow the steam from the hot wort to escape to disperse DMS (dimethtyl
>sulfide, the cooked vegetable smell)? If so, do you counterflow-chiller
>users wait a while before you start chillin'? How long is "long enough"?
Per George Fix, in "The Principles of Brewing Science", DMS precursors
have a 45 minute half life at boiling temperatures. DMS is volatile and
is quickly removed in the vapors of your boiling wort. A typical American
2 row malt will have the precursors reduced below the sensory threshold
after 2 or three half lifes. I guess that is why a 90 minute boil is
a good thing. Anyway, the conversion of precursors to DMS halts when
the wort is chilled. So all that is needed is to have the hot wort vented
In my case, I put the lid on my wort until ready to chill (about 10 minutes
waiting for the swirling to stop) and I had a pretty consistent DMS
problem. Since leavign the top off my kettle, I have not had a problem.
- Larry Barello
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