biertourist
Well-Known Member
I'm curious what equipment is required and what the process looks like to test for the presence of DMS in wort / finished beer.
So much of the professional literature focuses on macro brewery conditions that it's really hard to get good data that can be appropriately applied to home brewing-scale systems.
We know that the DMS precursor S-Methyl Methionine exists in malt and generally increases in quantity as the protein content of the malt increases, we know that SMM content is decreased as the kilning stage of malting continues and therefore the lightest color, least linked malts have the highest quantities of SMM and therefore the highest risk of DMS in finished wort / beer.
We certainly know that they keys to controlling DMS are having a rapid, uncovered boil to evolve off DMS as it forms and to rapidly chill below 160F after boiling to prevent additional amounts of SMM from forming into DMS and then being unable to escape. We also know that vigorous fermentations also help to evolve off DMS through CO2 evolution.
BUT, most of the estimates on the rate of DMS evolution during the boil are certainly based upon commercial mega lager brewery production and involve surface area to volume ratios that are many, MANY times smaller than the typical home brew-sized boil kettle.
We also know from these mega breweries and other studies that comercial calendria-based and "merlin" boil systems can evolve off DMS much, much faster than the typical rate in a "normal" large commercial brewery. -There's plenty of reasons to believe that because of the much higher surface area to volume ratio of a home brew 5 or 10 gallon batch that we should be evolving off much more DMS much faster than a typical commercial brewery. My hypothesis is that 90 minute boils for home brewers, for the purpose of DMS evolution, even when using 100% light lager / pilsner malt is an unnecessary practice and 60 minute boils at home brew scales will result in at least a 79% evolution of DMS. (The same as a 90 minute boil for the big guy.)
I'm considering filling for an AHA Research Fund scholarship to test my theory, so I'd like to know what type of equipment and test procedure I would need to measure DMS.
My plan would be to measure the DMS in wort in a typical keggle for a 10 gallon batch. I'd like to test a number of variables between batches and retest including: boil vigor (I have an electric brewery and can manually set the heat output for the boil), covered vs. uncovered boil, rapid chilling vs. slow / "no chill" brewing, 100% Continental Pilsner vs. 2 Row Pale vs. Lager Malt, DMS in wort vs. finished beer: split batch fermentation between vigorous 68F ale fermentation and 50F lager fermentation, and using CO2 to forcibly reduce DMS in finished beer (aeration stone in keg hooked up to CO2 bottle)- does it work?
Adam
So much of the professional literature focuses on macro brewery conditions that it's really hard to get good data that can be appropriately applied to home brewing-scale systems.
We know that the DMS precursor S-Methyl Methionine exists in malt and generally increases in quantity as the protein content of the malt increases, we know that SMM content is decreased as the kilning stage of malting continues and therefore the lightest color, least linked malts have the highest quantities of SMM and therefore the highest risk of DMS in finished wort / beer.
We certainly know that they keys to controlling DMS are having a rapid, uncovered boil to evolve off DMS as it forms and to rapidly chill below 160F after boiling to prevent additional amounts of SMM from forming into DMS and then being unable to escape. We also know that vigorous fermentations also help to evolve off DMS through CO2 evolution.
BUT, most of the estimates on the rate of DMS evolution during the boil are certainly based upon commercial mega lager brewery production and involve surface area to volume ratios that are many, MANY times smaller than the typical home brew-sized boil kettle.
We also know from these mega breweries and other studies that comercial calendria-based and "merlin" boil systems can evolve off DMS much, much faster than the typical rate in a "normal" large commercial brewery. -There's plenty of reasons to believe that because of the much higher surface area to volume ratio of a home brew 5 or 10 gallon batch that we should be evolving off much more DMS much faster than a typical commercial brewery. My hypothesis is that 90 minute boils for home brewers, for the purpose of DMS evolution, even when using 100% light lager / pilsner malt is an unnecessary practice and 60 minute boils at home brew scales will result in at least a 79% evolution of DMS. (The same as a 90 minute boil for the big guy.)
I'm considering filling for an AHA Research Fund scholarship to test my theory, so I'd like to know what type of equipment and test procedure I would need to measure DMS.
My plan would be to measure the DMS in wort in a typical keggle for a 10 gallon batch. I'd like to test a number of variables between batches and retest including: boil vigor (I have an electric brewery and can manually set the heat output for the boil), covered vs. uncovered boil, rapid chilling vs. slow / "no chill" brewing, 100% Continental Pilsner vs. 2 Row Pale vs. Lager Malt, DMS in wort vs. finished beer: split batch fermentation between vigorous 68F ale fermentation and 50F lager fermentation, and using CO2 to forcibly reduce DMS in finished beer (aeration stone in keg hooked up to CO2 bottle)- does it work?
Adam
