June 4, 2015 by fhsteinbart
Last time we talked about beers that were flawed by interaction with light and becoming skunked, yeast autolysis, and oxidation. This time around we’re going to go and see just how deep the rabbit hole goes!
Vegetative aromas and flavors in beer are indicative of either infection, or over utilization/excessive amounts of chlorophyllic compounds like those found in hops, and herbs. Sometimes limiting the boil will reduce this, but if you’re stuck with it, all you can do is either blend it out, cover it up, or dump the offending batch.
Another less usual but still common flaw as found in beer is the aroma, and flavor of what can best be described as nail polish, namely ethyl acetate. In small quantities it can contribute to complexity, but a little too much and it will taste like nail polish. All that you can do is the blend back, dilute it, cover it up, or dump the batch at this point in time.
One of the hardest off flavors to identify, correct, or ameliorate is the compound Isovaleric acid. This compound smells and tastes like a young kid goat, and in very small quantities, lends to complexity, especially in Belgian style beers. Unfortunately it frequently occurs when we use oxidized hops in our beer, and results in a flavor more akin to old sweaty gym socks than the pleasant aroma of say a gruyere cheese. Again, the only cure is prevention; the best solution to a cheesy beer is either dilution, blending back with a cleaner beer, covering it up, or simply dumping the beer.
As you can see from the past three essays on off flavors, there is little that you can do with an already damaged batch of beer, short of blending, covering, diluting, or dumping it. The best practices always involve prevention rather than cure, as dealing with problems ahead of time when they are more amenable to correction is easier than trying to resurrect a Frankenstein of a beer from the dead. Next week I’ll show you how you can make your own off flavor kit for around $50, rather than the usual $250~$300 you see in the world of professional sensory analysis. Cheers!