Boiled Corn Beer

One lesson I learned while traveling in Latin America was to always be skeptical of the corn cooked at street stands. In Mexico, old ladies are often seen taking beautiful ears of corn and boiling them in water for up to an hour. Once the corn is removed from the pot its chewy, flavorless, and unappetizing. The flavors most likely dissipate into the water, and by the end of the night I imagine the water is a pretty potent extract. Now, picture this extract being used as the base liquid for brewing beer; this is exactly what dimethyl sulfide tastes like. Many of you may know that this is also the smell of the sea, however brewers associate it with cooked vegetables.

For those interested in the chemistry I’ll give a quick explanation for how this flavor can arise during brewing, but if you have no such interest, skip this paragraph. S-methylmethionine, which is a derivative of the common amino acid methionine, is present in malted barley, and when its heated in the presence of a hydroxide (OH-), the positive sulfur atom bonded to the two methyl groups of s-methylmethionine are replaced by the hydroxide, forming both dimethyl sulfide and homoserin. As long as there is s-methylmethionine present, and the wort is at a temperature of at least 140°F, dimethyl sulfide will continue to be produced. However, dimethyl sulfide is extremely volatile and easily evaporates. It is also readily oxidized to dimethyl sulfoxide, which does not have a significant flavor impact on the finished product. Because s-methylmethionine continues to produce dimethyl sulfide as long as it is present in the wort, it is important to have a rolling boil for over an hour (90-120 minutes is optimal) with the lid off so that the volatile compounds can be carried away with the steam. This is also another reason why chilling the wort quickly is important.


Non-chemists are safe to start reading again. As a part of my independent study—and Matt McElwee’s and Christian Wagner’s—we wanted to see if we could successfully control and change the brewing process in order to produce both desirable and undesirable flavors. One of the easier off-flavors to produce is dimethyl sulfide, so we decided to brew a batch targeting this flavor. In order to produce our cooked-corn beer, we only boiled the wort for 30 minutes, and we left the lid on to capture any dimethyl sulfide that could evaporate during the boil. Once we finished the boil, we didn’t chill the wort with our copper chiller but allowed the wort to cool over night. Basically, we did the opposite of what is recommended to reduce the production of dimethyl sulfide.

The Test Batch: Corn Beer

Upon bottling this beer we knew we had been successful. The aroma of gross cooked corn was overwhelming to the point that we thought we would have to donate it to the beer pong table at a party. It has been a few weeks now since we bottled it, and its actually tolerable—if not refreshing. It will be a good beer for the winter when we’re all craving some corn on the cob or dreaming of Mexico.