The SOB Beer Blog
Our rants about beer and beer culture.
What you need to know about Keg beer
10.09.2012 18:10 PM
We were all keg virgins at one time or another. No shame in that. Rest easy, your old buddy SaveOnbrew is here to help you out via our buddies over at Micro Matic.
What You Need to Know About Kegs:
Alright, beer aficionados. This is where we get a little bit geeky, and look at the technology that goes into keeping our brews fresh on the way from brewer to beer mug. Technology? you ask. Yes, technology. Specifically, the technology of the keg.
Kegs are one of the main ways in which beer is transported around the world. Often overlooked as a mere container, beer kegs are actually specifically designed to do one thing and one thing only: bring your beer to you in the same condition in which it left the brewer, and serve it at the perfect temperature, with the perfect proportions of foam and carbonation.
The secret? One word: pressure.
In order to remain fresh and not go flat, beer needs to remain under a certain amount of pressure (exactly how much varies from beer to beer). There are two main factors in the keg that make sure that the beer stays under the right amount of pressure: the material, and the pump.
In the old days, when brewing was just beginning, beer was stored in wooden barrels. They were good for containing beer, and certainly gave good flavor, but porous wood is not the best material for maintaining proper pressure to transport beer long distances or keep the beer fresh for more than a few days after the barrel is tapped.
In the modern day, steel kegs are more commonly used.
Steel kegs are designed to withstand pressure, both from the outside (pressure of normal air on the outside of the barrel) and from the inside (pressure of the beer and CO2 on the inside of the barrel). The steel used today is designed not to affect the flavor of the beer in the container—though figuring out what specific alloy wouldn’t leave the beer with a metallic taste probably took a number of people a lot of time and effort (plus all that beer drinking in the name of research!).
Pumps are the next big factor (that's what she said!): you need a pump to get the beer out of the keg, but you want to make sure that as the beer exits, nothing else enters. A “party pump,” which is generally used (appropriately) at keg parties, maintains the pressure in the keg by pumping in oxygen as the beer is pumped out. That’s fine if you and your hundred houseguests are going to drink the entire keg within 36 hours, but if you need the keg to last longer without going flat, you need to maintain pressure without oxygen. This is where the “kegerator” comes into practice: basically you need to pump CO2 into the keg. This keeps O2 out of the beer and now the beer will last much longer in the keg—up to several months.
In addition to the traditional wooden keg and the now- standard steel keg, there’s a new type of keg on the market: plastic.
In part because production costs, and in part because weight, plastic kegs are coming into vogue. One such, the KeyKeg, is designed according to the principle of a bag in a ball. It’s a plastic keg with an, odorless, tasteless bag inside to hold the beer (more beer-drinking research!). The space between the bag and the ball is pressurized for transit, but when you tap it it can be pressurized with air. In other words, you get amazing fresh beer, without having to go through all the rigamarole of having a CO2 tank hovering next to your beer vessel.
Though the plastic bag-in-ball represents some of the newest technology in keg materials out there, you never know what might develop next. Rumor has it Bill Gates is trying to build a better beer keg, which means that new materials for uber-technologically advanced beer kegs might be just around the corner!
Diana Carlton is a writer for Micro Matic, makers of cutting edge draft beer dispensing technology. From keg to glass, Micro Matic supplies the highest quality draft beer equipment. Visit the Micro Matic website for all your draft beer accessory needs including keg couplers, tap handles and CO2 tanks.
This work is licensed under a Creative Commons Attribution 3.0 Unported License.
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