What’s in a slogan? Everybody’s heard that Budweiser is “beechwood aged,” but what does that actually mean? It turns out that it’s nothing like barrel aging or using oak—those techniques add tannins and vanillin and woody character, while beechwood’s flavor is fairly neutral. That makes perfect sense because Bud’s flavor is so delicate that actual wood character would overwhelm it. Instead, the idea is to speed up the lagering process and finish the beer quickly.
Theory and Commercial Practice
The process of lagering might seem somewhat passive, but it helps to mature the beer. There are a couple of different fermentation by-products that can be reduced by yeast during this step. The most common are acetaldehyde, which tastes like green apples, fresh pumpkin, or latex paint, and is diacetyl, which contributes a buttery or butterscotch flavor and aroma. Both chemicals can be reduced by contact with yeast, and lagering gives the yeast cells some more time to do their job.
Anheuser-Busch’s famous beechwood aging is designed to increase the contact area between the yeast and the beer. They start with long chunks of beechwood, which they treat with baking soda to reduce the already mild flavor contribution of the wood. A-B stacks these pieces in the Budweiser lagering tanks, and then they kräusen the beer by adding fresh wort. The wood forms a substrate to collect yeast, increasing the yeast/beer interface, as compared to a thicker layer of yeast at the bottom of the tank. It’s worth pointing out that they could probably get a similar effect using any non-reactive substrate, such as ceramic, although that wouldn’t make for good advertising.