Art & Science & Zeppelin

Brewers have real, first-hand knowledge of the truth behind the words of Led Zeppelin philosopher-king Robert Plant.

[Cue Zeppelin tune] Good times, bad times you know I’ve had my share …

Beer making has its share of ups and downs. Barrel-aging is no different. Lots of good-time rewards come your way, as you taste flavors like tart dried cherry, wisps of smoky oak, and buttery vanilla.

Bad times? Pitfalls exist, but can be avoided. Culprits include excessive oxidation, yeast autolysis, or rogue contaminants. Many can render a beer undrinkable, never good.

Some things to watch for:

  • Oxidation: Naturally, beer aging in barrels will come into contact with more oxygen, which impacts flavor and shelf stability. Oxidative flavor may provide a sought-after quality attribute (tawny port or sherry wine), but some oxidation by-products are loved by none and never welcome.
  • Yeast autolysis: If a barrel-aged beer “sits” on yeast too long, the yeast cells can “leak” resulting in almost meaty flavors. Autolysis provides flavor complexity, but is best in small doses.
  • Souring: A controversial topic. There’s a fine, subjective line between good sour and bad funk. Souring can happen when lactic acid bacteria or strains of yeast that produce more organic acids than ethanol, are introduced deliberately. When controlled, sour is a matter of taste as determined by the brewer. However, when these bacteria or yeast arrive uninvited, bad times may be knocking.
  • Wood: Oaky goodness is really good, but sometimes there can be too much wood flavor in barrel-aging. If a new barrel carries more than a light char, the beer will acquire too much of the phenolic, astringent character of wood extractives.

Big question: How to stick with the good and skirt the bad?

A brewer’s sense of smell and taste answers part, but not all, of this question. Alone, our senses can only take us so far. Lab data and analysis [Gas Chromatograph Mass Spectrophotometer is your friend!] and an obsession with Quality Assurance/Quality Control are essential. I’m thankful on a daily basis to the smart, scientific minds I encountered at UC Davis/Harpoon/BP and I’m still learning.

Brewing–even commercial brewing–is an art. And art and science go together. Science is the backbone that gets & keeps creativity up & running. Good times, go get your share.