Lets see if I can add to the discussion, but theres a lot of good info here already.
DMS = Dimethyl Sulfide = CH3-S-CH3
Cooked corn is the traditional aroma its described as. To me it is also like rotting cabbage or rotting vegetables in general. Its not an unpleasant aroma in small quantities, which threw me off for the longest time whilst trying to come to terms with it.
At very high concentrations it can smell like sewerage.
I can quite confidently say that in all my beer judge training, DMS is the last chemical that I could identify. I am pretty sure that I am one of the insensitive people for a start. But I think because it is so ubiquitous, its hard to give an easily identifiable example. However, other posts have reminded me of a good test...
DMS is produced in the boil, particularly from pilsner malts, thats why its common in lagers. But it is much more abundant when you use corn as an adjunct. Since the Americans do this a lot, their beers tend to have higher levels of DMS (but you'll find it in just about any lager). Anyway, Miller uses corn, but Budweiser uses rice as their adjunct of choice. so if you get a bottle of each, you should be able to smell the DMS as much more pronounced in the Miller.
BTW, DMS has not been detected in space yet, but I guess thats for another forum.
Berp.
