Beer is generally carbonated and often served at lower than room temperature. The character of the malts, hops and the brewing process in total contribute to the feel of the brew in the mouth.
Carbon dioxide bubbles interact with receptors on the tongue and influence whether the brew feels thick or light, creamy or thin. Brews run the gamut from metallic to astringent to warm and gentle. Some are lighter like a golden lager others are full-bodied.
Some beers, often as result of being spoiled or stored too long, are described as like cardboard or leather. Those characteristics are as much a matter of mouthfeel as flavor.
Often the aspect focused on most, flavor is rightly so the center of the beer tasting experience. Research suggests there are over a 1000 identifiable flavors in a given brew.
Of these, professional tasters can identify around 100 distinct flavors. The beginner will do well if he or she can find three or four. Work up to it. It’s a worthy goal.
Contemporary research suggests there is a large overlap between perceptions. It can be difficult to say how much is due to the physiology of the tongue and how much is contributed by the brain receptors. Neither functions without the other in any real setting.
Flavors can be sweet, sour, salty or bitter in line with the four traditional divisions of different parts of the tongue to which they are most sensitive. They go well beyond these categories, however.
This is brought out by recognizing that many flavors don’t fit neatly into any of the four categories. Sulfur may be said to be a combination of salty and bitter, for example. But in what category is phenolic, which has a mediciney quality like Band-Aids?
Some are described as clove-like, some butterscotchy, others coffee-like, or chlorinated, grassy, ‘alcoholic’ or even metallic. None of those are easy to fit into those neat divisions.
After swallowing, flavor and aroma combine to produce an aftertaste which is often distinctly different — even though caused by — the taste of the brew. Taste, after all, is a chemical reaction and it doesn’t stop when the majority of the liquid is cleared from the mouth.
Sweet caramel, grassy, soapy or oily, bitterness, spicy and many other qualities are all part of the experience of aftertaste. Balance between sweetness and bitterness is only part of the total.
The intensity of those qualities is also part of the aftertaste, often heavily influenced by the amount of alcohol in the brew. Alcohol evaporates more quickly than water and that helps volatize compounds that produce the aftertaste profile.
How long the aftertaste lasts is also part of the total experience. Some disappear quickly, others linger. Either can be good or bad, depending on the specifics.
The overall character of the brew is a function of all these factors. Drinkers will get the most out of a fine brew by not merely drinking, but tasting as well.