Beer Department: What is Bottle Conditioning?

If you pay attention to beer, you may have noticed various labels touting the words “bottle conditioned” or “refermented in the bottle.” These words are likely to appear on many Belgian or Belgian-style beers but may also be seen on stouts, barleywines, and occasionally even IPAs. Bottle conditioned beers will always be presented in glass bottles, almost always with a champagne-like cork and cage closure. While these terms and the techniques they describe may be widespread and better understood by wine lovers, their meaning is a little less clear among many beer enthusiasts.

Bottle conditioning refers to the practice of conditioning or dosing a bottle with a little pinch of live yeast and some sugar for the yeast to feed on. Just like yeast consumes sugar in order to create carbon dioxide and alcohol in the original fermentation at the brewery, this secondary fermentation or refermentation in the bottle will create additional carbon dioxide and potential increases in alcohol content. In wine, this process is legally required to produce sparkling wines like champagne or cava, where the process of bottle conditioning or refermentation in the bottle is called methode champenoise or methode traditionelle, the champagne method and traditional method, respectively. Since this additional fermentation creates additional carbon dioxide, gas pressure will build up inside the bottle. That’s why these beers (and wines) are packaged in heavy, thick glass bottles with sturdy cork and cage closures – to prevent the internal gas pressure from shattering the bottle and creating what we call a “bottle bomb.” This extra gas pressure is also the culprit behind the characteristic pop and fizz associated with pulling the cork on these beers and sparkling wines.

So what’s the benefit to bottle conditioning beer? It’s more labor intensive, the packaging is more expensive, and there’s a risk that the brewer might miscalculate the amount of sugar and yeast to add and may end up with exploding bottles. Why do it? Well, the most noticeable difference in a bottle conditioned beer, one that has achieved additional carbonation through fermentation in the bottle rather than relying solely on force injection carbonation like soda does, is that by forcing more carbon dioxide into the solution, the resulting beer will have much smaller, denser bubbles that provide a much creamier, rounded texture. Force injected beers will have larger bubbles in the beer’s head that dissipate quickly. Tighter bubbles not only provide better texture but will contribute to better aroma release. And hey, a big, pillowy head of tight bubbles on top of your beer is truly a thing of beauty.

The other major benefit to bottle conditioning a beer is that it will extend the beer’s shelf life. By creating additional fermentation in the beer, brewers are creating a living beer, one that is still developing weeks or even months after it leaves the brewery. Contrast this with beers that aren’t bottle conditioned, that can do nothing other than slowly deteriorate after packaging, and its pretty easy to understand why some brewers favor bottle conditioning. Additionally, the creation of extra carbon dioxide will displace any oxygen that might try to creep into the bottle neck and create unwanted oxidative flavors.

As to serving a bottle conditioned beer, there are multiple opinions out there and none of them are necessarily wrong; it’s more a matter of personal preference. When I learned proper bottle service, we were taught to pour the bottle gently and always on an angle so as to leave the yeast sediment undisturbed in the bottom. I personally prefer to pour a bit of the beer, swirl the bottle so as to agitate the yeast and then pour the remainder so that the yeast is evenly distributed throughout the served beer. Still others throw caution to the wind and favor a strong, hearty pour that not only redistributes the beer but also aerates the beer for additional aroma release. Whatever your preference, please know that drinking yeast won’t hurt you in the slightest. To the contrary, yeast contains plenty of vitamins and nutrients that are good for you. Do be aware that pouring a beer with yeast will make the beer much hazier in the glass. Again, this is no concern, but the yeast may cause the beer to taste ever so slightly more bitter. One major exception to this, and a caveat emptor to everyone, is to be very wary of beers with noticeably large floaters. These particulates can be an indication that the beer is too old and has begun breaking down on a molecular level. The clumps in the beer are actually the proteins in the beer coagulating. If you encounter a beer like this, do not drink it. Instead, promptly return it to wherever you got it.

So, there you have it,: a crash course on the wonders of bottle conditioning. Bottle conditioned beers really do offer a sensory experience that can’t be replicated by beers that don’t undergo this process and I thoroughly encourage everyone to seek them out. Cheers!

Eric, Eastgate

Certified Cicerone®