Thanks for tuning in to the second part of this series. If you haven’t yet, be sure to check out the first part, Smoke’s Preservative Effect on Aging Beer.

There’s a whole host of phenolic compounds present in beer, but three are much more common the others. Phenol itself, the most basic of phenolic compounds, gives smoke its pungent “smoky” flavor. Syringol, a more complicated phenol, has spicy, sausage-like flavor. And finally Isoeugenol lends a sweet, clove like smell and taste. These three not only provide tons of flavor in beer and food, but also provide protection from the staling effects of oxygen due to their strong anti-oxidative qualities.

The anti-oxidative abilities of phenolic molecules are due to the unique chemical structure they all share. Structurally, phenols are fairly close to alcohols - all have an oxygen and hydrogen molecule (called a hydroxyl group) attached to them at one end. Phenols differ from alcohols in that the carbon atoms attached to the hydroxyl group are arranged in a ring like structure (called an aromatic hydrocarbon group), instead of the straight line of carbon atoms typically seen in alcohols. This carbon ring seen in phenols can also have other groups of molecules hanging off of it, creating nearly endless possibilities for different kinds of phenols.

The upshoot of all of this chemistry is that it’s the ring-like structure of phenols that cause them to be very receptive to oxidative reactions. This is great new for our beer, as these molecules can take up a lot of the free oxygen in our beer before it has a chance to damage other, more sensitive flavor components.

It may be that beer is actually about a perfect vessel for smoke preservation that one can imagine. When food is smoked, phenols will gather all around the outside of the food, but very little actually penetrates the food being smoked. Beer, on the other hand, has no such problems. Smoke phenols are able to penetrate (and therefore protect) a brew completely due to its liquid nature. Also stacking up in beers favor is the closed off environment of the beer bottle (or keg for that matter), which means there is only a finite supply of oxygen for the phenols to deal with.

Unfortunately (or maybe not) phenols are not stable molecules. Eventually, they’ll start to break apart, and the smoky flavor of your brew will start to slip away. In the right beer, however, this can be a good thing. It means you’ll be treated to an ever changing flavor profile as the beer ages. It’s one of the big reasons, maybe THE reason, why every cellar enthusiast needs a few smoky beers tucked away somewhere.

I don’t know about you, but that’s enough science for me for one evening. I need a brew!

Jason

jason@brewbasement.com

www.brewbasement.com