The Different Flavor of Beer on Tap Bottled and canned beers and ales are generally cold stabilized and pasteurized (at 140–160ºF/60–70ºC) 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 Lagering The conditioning process for bottom-fermented beer is somewhat different The original Bavarian lager was packed in ice and allowed to rest in contact with its yeast dregs for several months The yeast slowly produced carbon dioxide, which helped purge the beer of sulfury off-odors Today, some traditional lagers are still aged for several months; but because storage has the economic disadvantage of tying up money and materials, the tendency is to lager the green beer at temperatures just above freezing for two to three weeks Carbon dioxide may be pumped in to purge undesired aromas; and centrifuges, filters, and additives help clarify the beer As a replacement for wooden casks, some beech or hazelwood chips may be thrown into the tank for flavor Additives More than 50 additives are permitted in American beer, including preservatives, foaming agents (usually vegetable gums), and enzymes — similar to ... the beer of sulfury off-odors Today, some traditional lagers are still aged for several months; but because storage has the economic disadvantage of tying up money and materials, the tendency is to lager the green...bottom-fermented beer is somewhat different The original Bavarian lager was packed in ice and allowed to rest in contact with its yeast dregs for several months The yeast slowly produced carbon dioxide, which helped purge the beer of sulfury off-odors... beer at temperatures just above freezing for two to three weeks Carbon dioxide may be pumped in to purge undesired aromas; and centrifuges, filters, and additives help clarify the beer As a replacement for wooden casks,