For ales, these sulfur-compound issues tend to disappear. For example, ale malt with only 1 μg of SMM per gram of malt is common. This low initial concentration means that the SMM level at the start of the boil is
This initial SMM concentration leaves a SMM residual of
at the end of the boil. As noted above, 50% of the sulfur-containing compounds (be they SMM or DMS) is removed in the fermentation. Thus, the finished beer will have sub threshold levels of DMS no matter how the wort is cooled. Indeed, any hint of DMS in ales is likely from technical brewing errors, most notably contamination (see chapter 3). This fact probably explains why ale aficionados react very negatively to DMS in any type of beer.
Fix, George. “Production and Reduction of Dimethyl Sulfide.” Principles of Brewing Science: a Study of Serious Brewing Issues. Boulder (Colo.): Brewers Publications, 1999. 71-75. Print.