I’m always looking for ways to improve efficiency and not waste resources and was wondering if decoctions are enough to drive off DMS as opposed to increasing boil times when using pilsner malt.
I don’t think Decoctions drive off DMS. Decoctions allow you to step up the temperature of the mash, allowing you to convert starches at each specific level. Normally we mash at 148-158 which converts most starches.
I believe DMS is driven off during the boil and thus longer boils are needed such as 90 mins for some pilsner malts. Others may chime in, as I haven’t done 90 min boils and have only done decoctions because I miss my mash temp- and then have to remove wort, bring it up to temp and re-introduce it
I suppose the decocted portion that you bring to a boil would lose some DMS, especially if you boil it for 15-30min. But I wouldn’t count on that driving off enough that you could reduce your boil time significantly.
On the other hand, if your grist is only partly pils or if you’re using 2-row, you can probably get away with a 60min boil.
Decoctions always give me a 5% boost in efficiency, I suppose due to the small starch granules being more completely gelatinized during boiling. So thats a better use of resources I suppose. Its offset by the extra energy to heat and the extra work, but I do it once in awhile jsut for fun.
A decoction might volatilize some of the compounds, but isn’t the same as a 90 minute boil. It’s probably pretty rare that you actually need a 90 minute boil, as DMS can also be driven off by a healthy ferment. A vigorous 60 minute boil is comparable to a less-than-vigorous 90 minute boil - it’s all about the rate of evaporation.
