fluketamer
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i know the consensus is to boil pilsner for 90 mins but what about 2 row . does this hold true for all light grains or is 60 mins more than enough for my 2 row.
(link)from a recipe at https://www.homebrewersassociation.org/homebrew-recipe/evil-twin/ the article said:... While you could go with a shorter boil, the 90 minute boil enhances the blood-red color.
The reason we used to boil pilsner for 90 minutes is because it had much more dms-causing chemicals in it, and the 90 minute boil would help get rid of that. It is no longer necessary.
DMS has a vapor point of 100F at standard pressure and does not form an azeotrope with water so as long as your pot is uncovered so it's not recondensing and dripping back in, you should be able to eliminate it even below a boiling point for wort.
It's more complicated than this. In most cases the rate-limiting step is not volatilization of the DMS, but conversion of the SMM precursor to DMS, which has a half-life of 35-40 minutes (depending on pH) at 100 C. The idea with a long boil is to deplete SMM levels so it doesn't convert later, when it's too late to remove the DMS. The half-life doubles approximately every 6 C, so even a bit lower temperature can have a big impact on the amount of SMM remaining, so this is a big deal for high-altitude brewing.DMS has a vapor point of 100F at standard pressure and does not form an azeotrope with water so as long as your pot is uncovered so it's not recondensing and dripping back in, you should be able to eliminate it even below a boiling point for wort.
Hop flavor extraction and alpha-acid isomerization, yes. Reduction of SMM precursor and DMS. Killing most unwanted organisms. Protein denaturation, followed by flocculation and thus clarification of the wort (some uncertainty about whether this is good.) Browning reactions (again, could be good or bad) for color and flavor development. And wort concentration. Did I miss anything?I'm kinda thinking boil is mostly about hops. longer for bittering, less for aroma.
If not for the hops...you could probably go from mash out to the fermenter?
But boil does ensure sterilization...meaning nothing alive in the wort to challenge the yeast. But you just need to reach boil, not stay there for any period of time.
DMS? never studied or thought about that much. But I've always boiled anyway. mash with the lid off?
Very little, if any DMS in the starting malt. DMS is formed by the breakdown of SMM, which is in the starting malt. The SMM to DMS conversion has a negligible rate below about 170°F, and SMM has a half life of 30-40 minutes (depending on wort pH) at 212°F. This means that half of the SMM can be converted to DMS (which then quickly evaporates, since its boiling point is about 100°F) in the first ~35 minutes of the boil, half of the SMM left after the first ~35 minutes is converted in the second ~35 minutes of boiling, and so on. Any remaining SMM can be converted to DMS by yeast during fermentation, but at ferm temps, DMS does not evaporate readily.DMS? never studied or thought about that much. But I've always boiled anyway. mash with the lid off?
Any remaining SMM can be converted to DMS by yeast during fermentation, but at ferm temps, DMS does not evaporate readily.
I'm working from memory, and may have gotten it wrong. But, if residual SMM isn't converted to DMS by something after the boil, then DMS would almost never be an issue. I'll go back and review the few papers I have on DMS.I think yeast can convert DMSO to DMS, but hadn't heard that yeast can convert SMM to DMS. Do you know of a scholarly source for the latter?
Here's a copy of one paper I have (attached below.) This paper does state that yeast do not convert SMM to DMS, but that yeast does convert DMSO to DMS. Both SMM and DMSO amounts are controlled primarily by the malting conditions - the DMSO being formed by oxidation of DMS formed by the breakdown of SMM during the malting process. I didn't find anything about DMSO being formed during the brewing process by oxidation of DMS, which is formed by breakdown of SMM at high temps.I think yeast can convert DMSO to DMS, but hadn't heard that yeast can convert SMM to DMS. Do you know of a scholarly source for the latter?
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