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.
Bringing it Home
Unless you have massive sealed lagering tanks, it’s tough to follow A-B’s process directly, but it can be scaled down. The closest simulation would be to kräusen your beer in a keg after inserting some larger chunks of treated beechwood. You want to use larger pieces that offer more surface area, rather than creating a denser pile of smaller chips at the bottom. You will need to treat your wood by boiling it in a solution of water and 3 Tbs of baking soda for at least two hours, then boiling in plain water for another hour. Once the keg is sealed, let the yeast cells work their way through the malt sugar in the kräusen. By the end of the lagering phase, the beer will be carbonated and officially “beechwood aged.”
As an alternative, if kräusening in a keg is impractical, you could just add the treated beechwood to the secondary, but you might need to use a bucket fermentor if you can’t fit the wood into a carboy. You’d still be able to say it was beechwood aged, but it wouldn’t mean as much because it wouldn’t benefit from the convection caused by the fermentation of the kräusen. That may not be such a big deal, though.
Should You Bother?
That is the big question. Personally, I don’t think it’s worth the hassle. Most lager breweries include a diacetyl rest in their fermentation schedule, and normal lagering does a good job of clearing out the acetaldehyde without requiring extended time to mature. So, I’m not convinced that beechwood aging has much effect at commercial scales.
It seems even less useful in homebrewing. Once again, a diacetyl rest is recommended, but, in my experience, there’s plenty of yeast available during the lagering phase to handle the acetaldehyde. If you do notice a strong green apple character in your beer, I’d recommend either giving the beer a little more time to age or switching to a less flocculent yeast strain before beechwood aging.
All in all, hand-crafted trumps beechwood aging, as Josh Weikert demonstrates in “Make Your Best Standard American Lager”.