In this article we will see how they work and what are they made of.
During kegs manufacturing process, the factory melts a particular steel, copper, nickel and manganese alloy which ensures to leave a smooth joint so there are no gaps in which bacteria could shelter and spoil the beer.
The result is an incredibly resistant keg capable of enduring the pressure of the inside fluid without busting, and resist the blows it will receive during the transportation to its destination.
Kegs of more than 5 liters are all reusable, which means that are returned to the brewery for refilling. The 5 liter mini keg is recyclable and it’s usually never returned back for refilling.
Barrels of beer must be sealed or oxygen could penetrate inside which would mean that beer would be spoiled within days. But since the beer must go out somehow, all pressurized barrels are equipped with a valve at the top that allows fluid to go out. This valve is connected to a tube called spear that almost reach the bottom of the keg, the spear is going to be used by the beer for raising to the valve.
In the other hand casks come equipped with a spigot at the bottom and an oxygen inlet at the top (if they operate by gravity) or an outlet for beer and a valve for pumping air (if they operate by air pressure).
For more information about Cask and Keg barrels types please visit this link.
Keg barrels type use CO2 or N2 as gas, the reason is that the CO2 gas is the same gas that beer naturally produce and it’s the gas that generates the bubbles and foam so inserting CO2 into the barrel does not harm the flavor or smell of the beer. Nitrogen is also near neutral so it usually doesn`t introduce any strange taste or flavor in beer.