This will be a series of articles, meant to outline both the theory and practice of pouring draft beer, and specifically “keg conditioned” draft beer. I think in order to understand something effectively, it’s best to start on a broad level, so as things get more complicated and specific, we can use our own logic to understand why certain processes work the way they do.
The goal of this article and those after it are to:
- Explain what keg conditioned draft beer is, and why it’s important.
- What the goal is when beer is poured on draft.
- Explain how pouring beer through a draft system works in both a practical and theoretical sense.
- Help you understand how to diagnose and remedy common issues that can occur when pouring “live” or keg conditioned beers.
What is keg conditioned draft beer?
Beer is an amazing, complex and delicious drink made and enjoyed around the world in thousands of ways. Most beers though have certain things in common. They’re made with malt, water, hops and yeast (as well as other ingredients) and for the most part, they’re carbonated. The carbonation provides the head of the beer, affects the way the beer feels when we drink it, and enhances flavor as well.
In terms of draft there is one thing that has the biggest effect in what needs to be done to pour beer that looks, tastes, and feels how the brewer intended, and that’s the level of carbonation. Carbonation is simply carbon dioxide that has been saturated into the beer under pressure. Carbonation can be either added to a beer through applying it from an outside source, much like soda or carbonated water, or can be created by yeast inside the beer, processing sugar into alcohol and co2. If the beer is sealed while this is happening, the yeast will create carbon dioxide and the beer will pressurize itself!
Now here’s where things get a little trickier. A liquid isn’t just “carbonated” or “not carbonated”. Depending on the amount of co2 inside the keg, the beer could either be almost completely still, or as bubbly as champagne with a huge scale in between. Now that being said, MOST beers you see at bars being poured on draft are at about the same level of carbonation, but not all of them are. For several reasons, one being some styles or brands of beer just aren’t supposed to taste and feel the same as other brews. A Bavarian Wheat beer with the same amount of Co2 as an IPA will just taste completely different. A stout with the same amount of co2 as a saison will just not be the same thing. The other is that the yeasts used behave differently in each beer. Some yeasts are very active, creating tons of flavor and carbonation, while others are much more subdued.
In addition to this, keg conditioned, living beers still have yeast alive inside them, so one keg of this beer might be different from the one next to it, and the same beer might be completely different after 3 months! This process is part of what makes these beers so complex and interesting. The continuous work of the yeast creating flavors over time, and it goes hand and hand with a varying level of carbonation.
Most beers are carbonated, and that level of carbonation varies between styles and specific beers. That is going to have a direct and massive effect on how they behave when they are poured from a keg or from a bottle. In the next article we will get into exactly how carbonation interacts with the systems used to tap kegs and pour draft beer.