Author Topic: Covering the Boil  (Read 1094 times)

Offline wamille

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Covering the Boil
« on: June 18, 2013, 12:42:46 AM »
I've heard (can't remember where) that some brewers are starting to cover the boiling wort near the very end of the boil to save hop aroma/flavors because most of the DMS has evaporated.  Has anyone else read this? Perhaps some of you have tried this personally?  Any thoughts or insights?

Offline phillamb168

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Re: Covering the Boil
« Reply #1 on: June 18, 2013, 03:44:20 AM »
Seems to me that once you've started smelling those aromas, they won't go back into the beer simply by putting a lid on the kettle. Hard to reverse that chemical process.
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Online erockrph

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Re: Re: Covering the Boil
« Reply #2 on: June 18, 2013, 04:54:37 AM »
Seems to me that once you've started smelling those aromas, they won't go back into the beer simply by putting a lid on the kettle. Hard to reverse that chemical process.

Evaporation is a physical process, not a chemical one, and you could theoretically recapture some of those oils if they condense on your lid and fall back into the kettle.

From a practical standpoint I think you would get a much greater effect by simply moving your aroma additions closer to flameout or doing a hop stand, etc.
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Offline theoman

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Re: Covering the Boil
« Reply #3 on: June 18, 2013, 05:04:49 AM »
Yeah, move additions to the end. It's safer than the inevitable boilover.

Offline duboman

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Re: Covering the Boil
« Reply #4 on: June 18, 2013, 05:49:27 AM »
It is my understanding that DMS does have the ability to return once the wort begins to drop below boiling temp and the lid prevents its escape.

I agree it is probably a better solution to add the hops later to achieve the aromas you desire instead of risking reformation of DMS.
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Online mtnrockhopper

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Re: Covering the Boil
« Reply #5 on: June 18, 2013, 05:57:28 AM »
Two problems with this are that DMS is constantly being created when boiling wort - and you'll never boil 100% of it out. There is good info here.
http://beersmith.com/blog/2012/04/10/dimethyl-sulfides-dms-in-home-brewed-beer/
 

I'd just move aroma additions later - even after flameout.
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Offline duboman

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Re: Covering the Boil
« Reply #6 on: June 18, 2013, 06:29:52 AM »
Two problems with this are that DMS is constantly being created when boiling wort - and you'll never boil 100% of it out. There is good info here.
http://beersmith.com/blog/2012/04/10/dimethyl-sulfides-dms-in-home-brewed-beer/
 

I'd just move aroma additions later - even after flameout.

That's what I remembered, Thanks for posting the article to refresh my memory!
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Offline brewmasternpb

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Re: Covering the Boil
« Reply #7 on: June 18, 2013, 10:27:24 PM »
Correct me if I'm wrong, but this effect will vary, depending on the Malt variety used...No?  For example, Pilsner Malt is going to have much more DMS than a 2 row pale malt.
I'd be more worried about messing up my total volume, because the evaporation would decrease, depending on how long you covered it for.
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Online mtnrockhopper

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Re: Covering the Boil
« Reply #8 on: June 19, 2013, 06:16:25 AM »
Yes, paler malts will have more DMS than less pale base malts. Heating during malting drives out DMS precursors and pilsener is heated less than regular 2-row. I think 6-row also creates more DMS than 2-row.
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Offline tomsawyer

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Re: Covering the Boil
« Reply #9 on: June 20, 2013, 09:07:29 AM »
I think a 60-90min boil gets rid of almost all the precursors to DMS so you could cover the kettle safely.  I agree about going to a flameout addition or a hop stand.
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