DMS production by time

[BrewingChemist]

Hi. I recently made a counter flow chiller. I read on Jamil's webpage that he recommends recirculating your chilled wort to avoid production of DMS. However, I have not been able to find a table that demonstrates clear percent production of DMS over time. My plan was to just chill and put directly into the fermenter. What do you guys do? Have you found a difference in DMS production?

My question is this. So SMM converts to DMS at 140F. And DMS boils off (roughly 79% in 90 minutes). So, wouldn't any SMM that is there from mashing be converted to DMS during the boil? and then boiled off? In which case, there wouldn't be anymore SMM to be converted to DMS during the cool off period.

Anyways, I would appreciate any thoughts on this topic. Thanks!

 

[mabrungard]

My understanding is that there is a limited SMM content in malt. Kilning drives off some of it, which is why pale malt is a little less prone to SMM and DMS production than the less kilned Pils malt. In addition, the length and vigor of the boil helps rid the wort of SMM and DMS. So a proper boil can significantly reduce the opportunity for that secondary production of DMS since much of the SMM has already been exhausted. The rule of thumb I've used is 60 minute minimum boil time for wort composed primarily of pale malt and 90 minutes for those composed primarily of pils malt.

I keep hearing of many commercial brewers that routinely have their wort at elevated temperature during whirlpooling and hop stand. My impression is that its less likely to incur DMS problems when the proper boiling is conducted. With all this said, I would be very interested in finding out more definitive information on DMS production.

 

[Hoser_brewing]

Ask and yet shall receive:

From our trusty friends at the Journal of the Institute of Brewing: DMS production and boil-off from wort and simulated wort:
http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1979.tb06845.x/abstract
PDF at:
http://onlinelibrary.wiley.com/stor...16.1979.tb06845.x.pdf?v=1&t=ht750oiw&4c970ea6

Without any SMM in the beer, all DMS is boiled off in about half an hour. When there's SMM, worst-case scenario is a 2-hr boil to get it all... But that was really the worst case.

If you go to our favourite brewing professor Dr. Bamforth:
Abstract: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1982.tb04101.x/abstract
PDF at: http://onlinelibrary.wiley.com/stor...16.1982.tb04101.x.pdf?v=1&t=ht74pxbb&9877505e

You can see how (p2) malting can affect the DMS and SMM levels in the finished malt; in general we're going to receive malts with fairly reduced DMS and SMM levels inherently in them.

If you want to read more, here are 211 articles all about DMS, go here and search for "Dimethyl Sulfide":
http://onlinelibrary.wiley.com/advanced/search/results

 

[mabrungard]

You are a good person!

 

[Calichusetts]

I believe the smm amounts are halved every 40 minutes of the boil...so only 50% ability of DMS after 40 minutes, 25% after 80 and 12% after 120:

http://beersmith.com/blog/2012/04/10/dimethyl-sulfides-dms-in-home-brewed-beer/