How long should you boil to ensure the absence of DMS in brewing?

To effectively reduce dimethyl sulfide (DMS) levels in the brewing process, it is crucial to boil the wort for an adequate duration. A 90-minute boil is widely recognized in the brewing community as an effective measure to prevent the presence of DMS in the final beer product.

DMS is a flavor compound that can produce undesirable off-flavors, often described as cooked corn or creamed corn. The compound is formed from the precursor S-methylmethionine (SMM) found in malt. During the boil, the heat causes SMM to convert to DMS, which can then evaporate if the boil is long enough and vigorous.

A 90-minute boil allows enough time for the DMS to evaporate, along with ensuring that the wort is adequately sterilized and that any unwanted volatile compounds are removed. This duration strikes a balance between efficiently removing DMS and achieving the desired bitterness from hops without risking over-concentration of flavors or creating other complications associated with prolonged boiling.

Other durations, such as 30 minutes, would typically be insufficient for reducing DMS, while durations like 60 and 120 minutes might not be optimal for all brewing scenarios, making 90 minutes the most recommended practice for achieving low DMS levels