« on: November 03, 2009, 08:48:27 PM »
What I would be concerned with is the extend to which DMS-P or SMM is converted to DMS during the extract production. Once DMS is formed, it is quickly evaporated especially since extract production evaporates all or most of the water. The remaining DMS-P concentration is a function of initial concentration (determined by the malt that was used), temperature and time and while I'm not an extract manufacturer, if I were one my first goal would be to minimize the energy used to make the extract. Essentially this means that I would minimize the boiling that is necessary.
As a result I would expect that there is a need to boil extract to make sure the amount of DMS precursor in the wort at flame-out is sufficiently low that you won't get excessive DMS formation between then and cooling. The amount of boiling necessary should however be less than what you would need for a comparable AG batch.
So much for the theory. I have little practical experience with using extract.