meat tenderizers — that break down proteins into smaller molecules that are less likely to cloud the brew Some companies avoid the use of preservatives, and usually advertise this fact on the label The Finished Beer In the end, brewing has transformed the dry, tasteless barley grain into a bubbly, bitter, acidic liquid (its pH is about 4) that is 90% water, to 6% alcohol, and between 2 and 10% carbohydrates, mainly the long-chain dextrins that provide body Storing and Serving Beer In contrast to wines, with their higher alcohol and antioxidant contents, most beers do not improve with age, and are at their best fresh from the brewery Oxidation causes the gradual development of a stale, cardboard aroma (from nonenal, a fatty-acid fragment) and harshness on the tongue (from hop phenolic substances) Browning reactions cause other undesirable changes Topfermented ales develop a solvent-like note Staling is slowed at low temperatures, so when possible beer should be stored in the cold Britain does make “laying-down beers,” and Belgium bières de garde, which start out fermentation with a very high soluble carbohydrate content and continue to ferment slowly in the bottle, the continuous production of carbon dioxide and other substances helping to prevent oxidation and staling They end with alcohol levels of 8% or more, and improve for a year or two Keep Beer in the Dark Beer should also be kept away from bright light, especially sunlight, and especially if it has been bottled in clear or green glass: otherwise it will develop a strong sulfurous odor A cup of beer at a picnic can go skunky in a few minutes; bottled beer in a fluorescent-lit display case ... Britain does make “laying-down beers,” and Belgium bières de garde, which start out fermentation with a very high soluble carbohydrate content and continue to ferment slowly in the bottle, the continuous production of carbon dioxide and other substances... slowly in the bottle, the continuous production of carbon dioxide and other substances helping to prevent oxidation and staling They end with alcohol levels of 8% or more, and improve for a year or two Keep Beer in the Dark Beer should... from bright light, especially sunlight, and especially if it has been bottled in clear or green glass: otherwise it will develop a strong sulfurous odor A cup of beer at a picnic can go skunky in