different yeast strains and the reduction of DMSO to DMS

I've been experimenting with some new yeast strains lately and also having trouble with DMS off flavors in beer. These flavors persist in spite of my having moved to a 2-hour boil, and using only pale ale base malt (instead of 2-row or pils). The DMS taste isn't detectable in the wort post-boil, but seems to appear only post-fermentation.

I *think* i've noticed that my batches that are fermented with certain yeasts are more likely to suffer from this off flavor, and batches fermented with other yeasts don't. I'm thinking that this may have to do with different yeasts having more ability to reduce DMSO in the wort (which can't be boiled off) to DMS.

DMS-tainted batches have been fermented with:
-French Saison 3711
-Belgian Ardennes 3522

DMS-free batches have been fermented with:
-Trappist High Gravity 3787
-Leuven Pale Ale 3538
-Champagne yeast ec-1118

Is there any data out there on the differences in reduction of DMSO to DMS by various strains? Is there any info available on levels of DMSO in base malts?

Are you boiling with a lid on your wort?

COLObrewer said:

Are you boiling with a lid on your wort?

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lol, no

Ok then, I know of no list that details DMS production (or DMS reduction) from different yeasts. There is a different amount of DMS in different grains (which is where the DMS originates) paler grains have more DMS. A couple of other things that could cause DMS flavors are; slow cooling after the boil, and/or infection. Are you certain it is DMS you're detecting?

It is my understanding the DMS is a byproduct of all yeast during fermentation. It is then consumed back by the yeast during the clean up phase post active fermentation

Perhaps you are not allowing enough time for this to occur or are moving the beer off the yeast cake to soon?

duboman said:

It is my understanding the DMS is a byproduct of all yeast during fermentation. . . . . .

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Hmmm, I've never heard or seen this anywhere, it seems we have conflicting information regarding DMS . . . .researching . . . . .

Edit, It seems we are both correct , kindof: http://beersmith.com/blog/2012/04/10/dimethyl-sulfides-dms-in-home-brewed-beer/

Brew on my friends

duboman said:

It is my understanding the DMS is a byproduct of all yeast during fermentation. It is then consumed back by the yeast during the clean up phase post active fermentation

Perhaps you are not allowing enough time for this to occur or are moving the beer off the yeast cake to soon?

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I know that yeast produce DMS during fermentation as a result of Breaking down the DMSO that occurs in the grain. But I hadn't heard that they can subsequently clean it back up? I thought that DMS is"baked into the cake" as it were...

I think slow cooling was the source of some dms in a belgian golden strong of mine. I realized this was because I always brew Belgians in the summer. Could it be a seasonal effect?


Under pitching can also cause dms.

duboman said:

It is my understanding the DMS is a byproduct of all yeast during fermentation. It is then consumed back by the yeast during the clean up phase post active fermentation

Perhaps you are not allowing enough time for this to occur or are moving the beer off the yeast cake to soon?

Click to expand...

It certainly SOUNDS LIKE you're describing diacetyl and not DMS...
Diacetyl is produced along the pathway to creating ethanol and gets "cleaned up" by the yeast later in fermentation (assuming that you didn't produce too much of it in the first place).

I agree with the other posters that a 2 hour boil with pale ale malt with the lid off followed by a rapid chilling should NOT result in a beer with much DMS. This doesn't sound like DMS.

Explain the off-flavor that you're noticing.

If it's a generally sulfury flavor, then there are other options. (Some lager strains can be very sulfury and many German hops have sulfur injected into the air used to dry them so that they look super green when dried, as a couple common examples.) -The Budwar strain is SOOO stinky sulfury...


Adam

biertourist said:

It certainly SOUNDS LIKE you're describing diacetyl and not DMS...
Diacetyl is produced along the pathway to creating ethanol and gets "cleaned up" by the yeast later in fermentation (assuming that you didn't produce too much of it in the first place).

I agree with the other posters that a 2 hour boil with pale ale malt with the lid off followed by a rapid chilling should NOT result in a beer with much DMS. This doesn't sound like DMS.

Explain the off-flavor that you're noticing.

If it's a generally sulfury flavor, then there are other options. (Some lager strains can be very sulfury and many German hops have sulfur injected into the air used to dry them so that they look super green when dried, as a couple common examples.) -The Budwar strain is SOOO stinky sulfury...

Adam

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Both diacetyl and DMS are byproduct of fermentation to some degree but I also agree with your take on this

biertourist said:

Explain the off-flavor that you're noticing.

If it's a generally sulfury flavor, then there are other options. (Some lager strains can be very sulfury and many German hops have sulfur injected into the air used to dry them so that they look super green when dried, as a couple common examples.) -The Budwar strain is SOOO stinky sulfury...


Adam

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It's not buttery or butterscotchy, not sulfury... it's maybe something like grits or husk, cooked vegetable notes. It is hard to describe and is a slight unpleasant aromatic quality in the aftertaste.

RBlagojevich said:

It's not buttery or butterscotchy, not sulfury... it's maybe something like grits or husk, cooked vegetable notes. It is hard to describe and is a slight unpleasant aromatic quality in the aftertaste.

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Cooked veggies is DMS

See this: http://www.kroc.org/Links/TroubleshootingGuide.htm

:\ I know. Hence my question?

Maybe the flavor I'm getting is from chloramines. Meh.

For the record. I have had similar experience with Belgian yeasts. Used Pale ale malt and I did no-chill so I am asking for it a bit. I plan to do an extract batch with the same yeast and see how that differs.