Most keg draft beers brewed in the U.S. and some keg draft beers in Australia are not pasteurized during brewing. During the packaging process non-pasteurized draft beers are chilled to the point that the bacteria which ferments the beer becomes dormant.

Temperatures above 38°F(3 ℃) will cause non-pasteurized draft beers to foam and promote sour/cloudy beer. Should the temperature of non-pasteurized draft beers rise above 50-55°F(or above 10 ℃), the dormant bacteria which ferments the beer will once again become active, and growth will rapidly begin to spoil flavor and cloud the beer. This is commonly referred to as secondary fermentation.

Therefore,non-pasteurized beers must be stored in a keg fridge to keep the beer chilled.The Kegerator is a residential draft (draught) beer dispensing device,which can maintain a tapped keg in such a device for extended periods of time, usually a couple of months, without losing any quality in the taste of the beer.

The kegerator allows people to have draft beer at home and save money.

Most keg draft beers brewed in Europe as well can and bottle beers in the U.S. and Australia, are heat pasteurized during brewing. This process kills off the bacteria that ferment the beer.

Therefore, Pasteurized beers can be stored at room temperature and chilled at the point of dispense by use of a flash chiller.