Beer Department: Barrel Aging vs. Barrel Fermenting

Back to feed
​The interplay of beer and wood is complex and somewhat daunting to fully grasp. I won’t pretend to be able to cover it all here – for an in-depth exploration of everything you’d ever need to know, I strongly recommend Wood and Beer by Dick Cantwell and Peter Bouckaert. What’s important for our purposes is to know that some styles of beer, by definition, come into contact with wood. ​ Ambitious brewers today are even exposing beers that traditionally saw no wood whatsoever to wood in ​the hopes of deriving
new flavors, aromas and structural elements. The wood in question is nearly always oak. The size of the oak vessel will affect the beer differently, i.e. smaller barrels will exert a greater influence over the beer as the ratio of beer to wood is lower. Where the wood hails from is also important. Oak from America, France, Slovenia or Hungary all function differently and act upon the beer in unique ways. The level of toast or char as well as anything that was previously held in the barrels will also carry over into the beer.

One of the most important aspects to understand in evaluating wood’s influence on beer is knowing whether the beer was merely aged in wood or if the fermentation actually took place in wood. Perhaps the best known example of a barrel aged beer is Kentucky Bourbon Barrel Ale from Alltech’s Lexington Brewing Co. This beer is their standard ale, an amber ale, that is fermented in typical stainless steel fermenters. After the beer is finished fermenting, the completed beer is transferred into oak bourbon barrels for six weeks where it picks up flavors of vanilla and baking spices that has endeared the beer to untold thousands of adoring fans.

​By contrast, a barrel fermented beer will be transferred directly into oak vessels immediately upon leaving the brew kettle. Here, the wort (unfermented beer) will spend the entirety of its fermentation in wood, be that big foudres, wine barrels, bourbon barrels, clean oak, or whatever else it might be. Because the very lively process of fermentation is taking place in wood, the wood becomes a much more active participant in leaving its fingerprint on the final beer. 
Fermentation creates heat and carbon dioxide that puts pressure on the walls of the wooden vessels, thereby causing the wood to expand and then contract, absorbing and then depositing beer in an intricate dance that leaves behind unique, unmistakable characteristics in the beer. Barrel fermented beers have wood notes that are far more nuanced than their barrel aged counterparts. They are truly unique beers and express a great deal of time, love and attention to detail on the brewer’s part. If you’re looking to get your feet wet with barrel fermented beers, Hi-Wire and The Bruery both make a number of outstanding examples that are all more than worth your time. If you have any questions, as always, we’re here to help.

Cheers! Eric – Eastgate

Back to Top