ABV (alcohol by volume). Beers under 5 percent ABV are considered low-alcohol or “session” beers. Brews above 8 percent are strong, while those higher than 10 percent are considered “extreme.”
Ale. One of the two main types of beer, along with lager. Ales are brewed at warm temperatures with top-fermenting yeasts. They come in a wide variety of styles—from refreshing saisons to heavy stouts—and can be more complex than lagers.
Barley wine. Strong, malty ales first brewed in England as a wine substitute in wealthy households. American barley wines, such as Sierra Nevada Bigfoot, tend to be hoppier and higher in alcohol than their English-style counterparts.
Barrel aging. The process of putting beer in oak barrels to draw flavor from the wood as well as whatever was aged in it before. Bourbon and whiskey barrels are most common, but other spirits, wine, and maple-syrup barrels are in vogue.
Bottle-conditioned. A term for beer packaged with live yeast that releases small amounts of carbon dioxide. It’s often done for flavor but also extends drinkability and allows for aging, or cellaring.
Cask (or firkin). A small container traditionally made of wood. Beer becomes “real ale” or cask ale when conditioned inside a cask with live yeast. Brewers also use casks to add ingredients such as vanilla beans to spiff up a beer.
Growler. A reusable glass or ceramic container—sizes vary, but a half gallon is standard—that keeps draft beer fresh for about a week unopened, or for two to three days after opening.
Hops. The cone-like flowers of the vine Humulus lupulus that give beer bitterness, aromas, and flavors including grass, grapefruit, and herbs.
IBU. A measurement (standing for international bitterness unit) on a scale from 0 to 100 that indicates a beer’s bitterness. A standard IPA is about 55 IBUs, while a less hoppy hefeweizen is about 15.
India Pale Ale (IPA). Originally, a stronger, hoppier version of the British pale ale that traveled well to India. US brew-ers such as Sierra Nevada have made IPAs synonymous with citrusy West Coast hops.
Lager. Beer made with bottom-fermenting yeast and stored at cold temperatures for one to three months. Lagers tend to have cleaner flavors more focused on malt and hops than ales do. Czech-style Pilsner and German-style bock are prime examples, but light lagers such as Budweiser are the best known.
Malt. A grain, typically barley, that has been allowed to sprout. Malted grain provides the proteins and sugars needed by yeast to produce alcohol during fermentation. Malt imparts sweetness and bready, caramel, and roast flavors in beer.
Sour beers. Funky, often tart beers such as Belgian lambic and German Berliner weisse. Most are brewed with Brettanomyces yeast (“Brett”) or the bacterium Lactobacillus, but some are made with wild yeasts captured during open-vessel fermentation.
Stout or porter. “Stout” originally described a stronger version of any British ale, while “porter” supposedly referred to a blended brown beer favored by porters who delivered goods in London. They have become interchangeable words for a diverse group of dark beers with roasted-barley, coffee, and chocolate flavors. The most familiar is Guinness’s Irish dry stout.
Tripel and dubbel. Two Belgian-abbey styles of beer. Tripels are strong, often dry, golden ales with fruity and spicy characteristics. Dubbels are brown beers with caramel and raisin flavors.
Wheat beer. Any brew with a significant portion of wheat, which makes beer hazy, lighter-bodied, and slightly acidic. German hefeweizens and Belgian-style wits are the predominant types.
Yeast. Microscopic fungi that eat the sugars in wort (unfermented beer) to produce alcohol and carbon dioxide. The different strains of ale yeasts result in distinct spicy or fruity characteristics in beer.