The treatment of beer after fermentation varies according to the type of fermentation that has taken place: brief for fast top fermentation, prolonged for slow bottom fermentation.
The Different Flavor of Beer on Tap
Bottled and canned beers and ales are generally cold stabilized and pasteurized (at 140–160°F/60–70°C) to survive extreme temperatures during shipping and storage, while keg beers, which are kept refrigerated continuously, may not be. This is why bottle and keg versions of the same beer can taste very different. However, even keg beer is a world apart from the traditional cask-conditioned beer. Keg beer has been cleared of all its yeast before the keg is filled, while in cask conditioning, the new beer and the yeast that will help mature it are sealed together in the cask. Cask-conditioned beer is thus in contact with yeast until the moment it’s dispensed, and its flavor reflects this. Cask beer is fragile and has a drinkable life of about a month, compared with three months for keg beer.
