Beer Tasting Class: Off-Flavors

I signed up for a class on “common off-flavors” in beers and it turned out to be a really interesting workshop on what can go wrong in the brewing process, and why. It was led by Mary Izzet and she covered seven off-flavors, using Miller Lite as the “control beer,” with all but the last off-flavor demonstrated with it.

While it was more for the home-brewing crowd and a little over my head, it was fascinating to learn how these off-flavors happen, and these are the rather simple notes I took for each one as we went along:

• Acetaldehyde: A subtle apple aroma with a rather flat taste. Reminded me of most commercial domestic lagers.
• Dimethyl suflide (DMS): A really grainy aroma that smelled like boiled vegetables and didn’t taste good at all.
• Astringent: I couldn’t pick up anything from this one, but she noted it’s identified by a tart, dry taste that gives a tingling sensation. At the end of the class, she noted hoppy IPAs (one of my favorite styles) is where it’s common and, at the right levels, acceptable.
• Acetic: On the first pass, it tasted like plastic, but she added a couple of more drops of vinegar to bring out the sour aroma and taste. Not pleasant.
• Chlorophenol: This one smelled and tasted like plastic (one of the descriptors is “Band-Aid”) and made me gag it was so gross.
• Diacetyl: A slightly buttery aroma, it wasn’t awful but it was way too smooth in my mouth.
• Isopentyl Mercaptan: aka, Skunky beer. For this one she gave us Coronas she’d left out on her fire escape for a day and then refrigerated, and the smell was so revolting I could barely take a sip. Oddly, it was reminiscent of Heineken, one of the first beers I drank regularly and now can’t bear the smell of.

We wrapped up with a good beer, Founders’ Centennial IPA, nice and hoppy and a perfect ending to a fascinating session. I don’t forsee myself ever getting into home-brewing, but I like learning more about the process so I can not only know what I like, but why I like it.