boiling length and evaporation - effect on DMS removal

[mike_g08]

Hello.

I recently was digging into the subject of DMS removal, as it is related to evaporation rate, and length of boil. I was hoping a 30 minute boil with larger evap rate would take care of DMS (I do a split boil).

Here is an interesting study on the topic: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1979.tb06845.x/pdf

It appears that evaporation rate does not have as much effect on DMS removal as time spent at boiling temps.

In that regard, I read also (different source) that decoctions help remove DMS due to the boiling of the malt.


The upshot for me, based on a bunch of reading, is to use a 60-90 minute boil unless using darker-klined malt in a style where DMS won't be noticed: in that case, I think a 30 minute boil would be sufficient, especially if using FWH hops (bittering is equal to or greater than 60 minute hops).

 

[JLeuck64]

Wow, there is SO much science in this hobby! Every little aspect has it's own research that folks have spent a LOT of time investigating!

 

[brew_ny]

Wow, there is SO much science in this hobby!

or too much science

 

[Bmoney1215]

Check this prodcast out. These guys do an experiment with a 60 min boil and a 15 min boil using extract. Its the link that is on 9/8/2014
http://www.basicbrewing.com/index.php?page=basic-brewing-radio-2014

 

[RM-MN]

Hello.

I recently was digging into the subject of DMS removal, as it is related to evaporation rate, and length of boil. I was hoping a 30 minute boil with larger evap rate would take care of DMS (I do a split boil).

Here is an interesting study on the topic: http://onlinelibrary.wiley.com/doi/10.1002/j.2050-0416.1979.tb06845.x/pdf

It appears that evaporation rate does not have as much effect on DMS removal as time spent at boiling temps.

In that regard, I read also (different source) that decoctions help remove DMS due to the boiling of the malt.


The upshot for me, based on a bunch of reading, is to use a 60-90 minute boil unless using darker-klined malt in a style where DMS won't be noticed: in that case, I think a 30 minute boil would be sufficient, especially if using FWH hops (bittering is equal to or greater than 60 minute hops).

There have been studies on the removal of DMS that will tell you the amount removed per unit time boiling. There are other studies that will tell you the amount removed by the activity of the yeast. What doesn't appear to be so readily available is the total amount removed by both together, nor do the studies consider that much of the malts available from new world malters don't have much left in the malts to be removed.

 

[mike_g08]

I agree, sometimes too much science can keep a person from actually brewing or doing other worthwhile activities...

With regard to short boil extract batches: I don't think DMS is much of a concern with extract, given that it is pre-cooked and evaporated to concentrate it. I have seen a fair amount of discussion of 15 minute batches with extract - which is probably fine. I pretty much exclusively do all grain.

RM - yes, no studies for each person's specific batch, unfortunately. This study did measure DMS at various stages thru finished beer, even with two different yeast strains, and two different malts. But, I didn't see a test of a 1.040 lager brewed with 80% rahr 2-row, 20% corn, 2124 yeast, my water profile, etc. I guess it comes back to individual experimentation and knowing your system.

In the spirit of individual experimentation, I read an interesting post yesterday on a 30 minute APA experiment, which may be of interest: http://brulosophy.com/2015/03/11/the-impact-of-boil-length-ale-exbeeriment-results/