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?
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.
Yeah, move additions to the end. It’s safer than the inevitable boilover.
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.
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!
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.
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.
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.