Beer Handling and Flavor Protection After the Brewery
The three enemies: light, oxygen, and heat
Beer leaves the brewery fresh and then begins to change. Light breaks down hop compounds into a skunky, mercaptan-like aroma, which is why brown bottles protect better than green or clear ones. Oxygen stales beer, producing cardboard or sherry notes. Heat accelerates every staling reaction, so a warm storeroom ages beer far faster than a cold one.
Storage and handling
Store beer cool, dark, and upright, away from strong odors. Keep it out of direct sunlight and away from fluorescent light. Minimize temperature swings; a back room that heats and cools is worse than a steady cool room. Do not shake kegs, and keep kegs cold and pressurized. Observe date codes and rotate stock first in, first out.
Draft systems protect flavor
Draft lines must be cleaned on a regular schedule, commonly about every two weeks, and the gas must be balanced to the system so beer is neither flat nor foamy. A dirty line gives off-flavors and haze; a badly balanced line pours foam.
Traps in questions
Questions may suggest that refrigeration reverses staling, that green bottles block light, or that a keg can be stored warm as long as it is chilled before serving. None of these are true.
Rule of thumb
Brown glass plus cold, dark, upright storage plus a clean draft line equals the best chance of tasting the beer the brewer intended.