If you’ve been a long-time subscriber of the ol’ TOB Monthly Mash (thank ya!), you’ll know that older editions contained a segment called “Beer School” where we wrote about a beer-related subject. Well, we’re bringing it back!
This week we’re talking about beer gas. And no, not the kind of gas you get after a long night of drinking.
A natural byproduct of beer fermentation is carbon dioxide (CO2). And because all beer is fermented (otherwise it wouldn’t be beer), all beers contain some level of CO2. However, you may notice that some beers you drink are “nitro” beers, meaning they contain a gas called nitrogen. So (here’s everyone’s favorite question)…
What’s the difference between CO2 and nitrogen in beer?
When you see the word “nitrogen” used on a beer label or draft menu, that’s a reference to the gas dissolved in the beer. However, a nitro beer is typically a blend of both CO2 and nitrogen (typically 70% to 30%, respectively). It is worth noting that nitrogen is not fully soluble in beer, and the cascading effect you see after pouring a nitro beer is due to the nitrogen gas escaping the solution (beer).
Nitro beers offer a different experience with a creamier mouthfeel, and typically work well with maltier styles of beer (stout, porter, ESB, etc)
On the other hand, CO2 is fully soluble and will take a considerable amount of time to decarbonate.
Now we’ve laid out a loose understanding of CO2 and nitrogen in beer, you should also know that beer gas has different purposes. As we’ve mentioned, the type of gas used can offer a specific kind of mouthfeel when you drink beer. Think about that “prickly” feeling you get when drinking a effervescent saison. Now think about that beer you left on your kitchen counter over night and, despite your better judgment, you decided to take a sip the next morning. Flat beer (boooo), right? It has a relatively thicker mouthfeel now that’s decarbonated.
Secondly, gas can provide flavor. Yes, even the gas in your beer attributes flavor in your beer. Carbonic acid can make a beer taste more – well, acidic. We also think it can add a sharpness, and increased perceived bitterness as well.
Lastly, gas is used to dispense beer on a draft system. Without getting into the technical specifics of draft beer systems, just know that in this simplest example, beer runs from a keg, through a tube, and finally to the faucet of a draft tower into your glass. Just like your kitchen’s water faucet, beer needs to be released with some sort of pressure when a draft faucet is opened (kitchen beer faucet anyone?). CO2 will always be used to dispense beer in a properly installed draft beer system. For the love of God, never oxygen. Because draft beer has to run long distances, gas pressure is essential in order to combat resistance (gravity, surface resistance, etc.) and get beer from point A to point B.
We could go on. There’s plenty more to cover about beer gas (maybe we’ll touch on it with another post), but for now that’s that. Beer + gas live happily ever after!