Beer

Beer is made from four ingredients: malted barley, hops, water and yeast. Barley is soaked and allowed to germinate, then dried in a kiln, which produces malt, grain whose starch can be turned into sugar. Hops are the flower cones of a climbing plant and supply bitterness, aroma and some preservative effect. Yeast does the fermenting. Water is most of the finished product, and its mineral content shapes the style.

Many mass-market beers also use an adjunct, a cheaper starch added to the barley. Budweiser is brewed with rice and Bud Light follows the same template, which is how American lagers end up lighter in body and flavor than an all-malt beer such as Heineken.

How beer is made

Brewing starts with mashing: crushed malt is steeped in hot water, and enzymes in the grain convert starch into sugars. The liquid is drained from the spent grain and boiled with hops, which sterilises it and extracts the bitterness. It is then cooled and the yeast is added. Fermentation turns most of the sugar into ethanol and carbon dioxide.

Not all of it. Yeast ferments the simple sugars, mainly maltose and maltotriose, but cannot ferment dextrins, the longer starch chains left over from mashing. Those stay in the finished beer as carbohydrate. The balance between the two is set during the mash, and it is why one 5% beer can be thinner or heavier than another.

Lager vs ale

Every beer is either an ale or a lager, and the difference is the yeast. Ale yeast ferments warm and fast and throws fruity, spicy flavors. Lager yeast ferments cold, then the beer is conditioned cold for weeks, which gives a cleaner, crisper result. Stout, porter, IPA, wheat beer and sours are ales. Pilsner, Mexican lager and most light beer are lagers. The full breakdown of styles, with each one scored, is in the different types of beer.

Calories, carbs and sugar

A beer’s calories come from two places: the alcohol and the leftover carbohydrate. Alcohol carries about 7 calories per gram, so strength matters as much as malt. The labelled figures this site uses show the range for a 12oz serving: Michelob Ultra is 95 calories and 2.6g of carbohydrate, Bud Light about 110 calories and 6.6g, Budweiser 145 calories and 10.6g, and Heineken 142 calories and 11g. Guinness Draught looks heavy but is about 125 calories and 10.6g, because the dark color comes from roasted barley, not sugar. If calories are the question, the healthiest beer ranking sorts the options, and IPA vs light beer shows what strength costs.

What beer does to a hangover

Beer is lower in alcohol per drink than wine or spirits, but people drink it by volume, so the total ethanol adds up quickly. Fermentation also produces biogenic amines such as histamine and tyramine, which is why the profile above rates histamines high. Barley means gluten for anyone sensitive, and the fermentable carbohydrates are an issue for people who react to FODMAPs. Unfiltered and hazy beers keep more protein in suspension, and sour styles carry more lactic acid and amines than a clean lager.

For a comparison against other drinks, see beer vs red wine, beer vs vodka and IPA vs stout.