Originally Posted by duboman
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?
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...