The microbrewing industry in the US took off in the mid 1980s thanks in part to Samuel Adams on the east coast and New Albion and Anchor Brewing on the west. Since then it has been a fast-growing niche pushed along by an assortment of fads and trends, some of which were adopted as canon (clever or suggestive labels sell beer) while some remained on the fringe (chile peppers in beer).
There have been periods where stouts and porters were the hip thing, and other times when the use (and frequent overuse) of hops is what made a brewery popular. Events surrounding the release of specific beers always builds hype - for example, in Iowa City there is the annual Blessing of the Bock, complete with Gothic chants, incense, priestly robes and a red-hot loggerhead, which a monk will plunge into your beer to caramelize the sugars. This oddity is highly recommended.
The new trend now is not new at all. Sour beers are showing up on better beer lists across the country. Once, all beer was made in this manner, trusting in the wild yeasts that floated by in the air even before anyone new what "yeast" was. Beer is liquid bread, and like bread it needs yeast to "rise." Before Louis Pasteur, bakers and brewers alike took their chances with the wild microorganisms that happened to be floating by, and that also gave rise to different beers, breads and even cheeses being made during specific seasons. Just because a brewer didn't know what yeast was, did not mean he wouldn't notice that the Bock was better when brewed in February.
In Belgian Monasteries, where some would argue the brewer's art was perfected, they would hoist great long troughs of wort (pronounced "wert," it's the liquid beer before it is fermented) on rope-and-pulley systems up the high ceilings of the brewery, open the louvered windows, and let the Belgian breeze work its magic.
Once Pasteur pulled back the curtain on what was really going on, biochemistry invaded the artisan-controlled world of brewing, with both up- and downsides. Brewers had much more control over the process, and could steer fermentation in specific directions to achieve desired results. They isolated and propagated specific strains of yeast - often zealously guarding it as proprietary - and because of their strong control, they could mass-produce an identical beer anywhere and in any season.
By the time Repeal occurred here in the US in 1933-34, nearly all the nations breweries were gone. Only the largest had survived by making yeast and "near-beer" - a malt beverage with no alcohol, similar in taste and quality to today's "O'Doul's" or other non-alcoholic "beers." Tight government regulation of brewing made it impossible for small breweries to survive. The big breweries revved-up their production as if on a war footing, and soon the nation was awash in adjunct light lager, which was cheap and easy to produce, approachable by almost any palate, and refreshing if chilled in America's ice boxes and its new refrigerators.
In 1979 President Carter lifted the regulations that precluded small breweries. At the time there were less than 100 breweries in the US. Today, according to the Brewers Association, there are over 3,000 making an enormous variety of beers, even occasionally forcing the mega-breweries into acknowledging the successes of the little guys through imitation, and occasionally through buyouts. America's beer tastes are wide and varied, but the one thing the brewery boom has proven is that Americans increasingly want one thing in their beer: flavor.
Yeast, when combined with sugar and water, will produce three things: Alcohol, carbon dioxide, and flavor. While the methods of the Belgian monks and their open-air yeast harvests may seem quaint, they are not very popular with risk-averse American business fearing an inconsistent product, so today's sour beers are usually given their tart aspects one or both of two ways. Brewers may use specific yeasts, such as Brettanomyces, Lactobacillus, or Pediococcus, which impart such sour aspects, or they may introduce fruit in the style of legendary Belgian Lambic ales like Kriek, Framboise or Peche.
There are six primary forms of sour beers: American Wild Ale, Berliner Weisse, Flanders Red Ale, Gose, Lambic and Oud Bruin.
American Wild Ale is a sort of catch-all term for US beers that rely in whole or in part upon the capture of wild yeast and bacteria strains. While often delicious, they are also inconsistent, and a beer you thought you liked one year may taste very differently the next. That can be disappointing or exciting.
Berliner Weisse is among the better-known versions of sours, made with Lactobacillus, which turns sugars into lactic acid, providing the sour flavor. They are often low in alcohol, and are sometimes served with flavored syrups to offset the sour.
Things get more interesting with the Flanders Red Ale. A descendant of English Porter, the Flanders Red is fermented with typical brewers yeast, then aged in oak barrels, then blended with younger beer.
Gose is certainly an acquired taste. The name comes from its origin (Goslar, Germany). It is top-fermented, which is to say it is fermented at temperatures high enough to carry the yeast to the top of the wort. Brewers use the addition of coriander and salt for its unique flavor, and add lactic acid for the sour aspect.
True Lambic is the beer referred to earlier, hoisted to the ceilings of Belgian monasteries. It is usually blended from various batches and infused with fruit.
Oud Bruin is a Flemish brew, similar to the Flanders Red Ale, though it is darker and is not aged.
Perhaps the best-known, most successful brewery in America that specializes in sours is Jolly Pumpkin, the ebullient brewery of "Captain Spooky" Ron Jeffries in Dexter, Michigan (outside Ann Arbor). With some 40 beers in their repertoire, they are able to show the diversity of the category while remaining approachable and branching out into other, primarily Belgian varieties, and experimenting with unusual flavor additions like Thai basil. Among their most fascinating "Calabaza Blanca," a white ale spiced with orange peel and coriander.
They are of course not alone. Lots of America's best breweries have ventured into "funky fermentation." The now-ubiquitous New Belgium Brewery has had "La Folie" rotating through their tanks since 1997. In Bend, Oregon, Deschutes is producing and Oud Bruin called "Dissident" that is fermented (n.b. not aged, feremented) for 18 months. About 90 miles west of Jolly Pumpkin in Kalamazoo, Michigan, Bell's Brewery - mostly known for their proficiency with hops - is making perhaps the most widely-available sour in the US. It's a Berliner Weisse called "Oarsman" than can be found almost anywhere better beers are sold, in six-packs for about ten bucks. And at a meager 4 percent alcohol, it's the perfect choice for a sour "session beer."
Also in Michigan, New Holland Brewing makes a white sour ale in its "Cellar Series" that they have labeled "Incorrigible," and that it surely is. They call that cellar "The House of Funk," and it has yielded a tart, refreshing session beer, perfect for a hot day on the deck or the beach.
Meanwhile Brooklyn's Evil Twin Brewing has taken a novel approach, sourcing beers from 10 breweries around the world and marketing them under the Evil Twin name. They have a stimulating sour called Mission Gose, with just a hint of eucalyptus of all things.
Having said all this, a confession: I was not a fan of sour beer until very recently, having always been a devoted hophead with a pronounced preference for the bitter over the sour. My wife always liked it, so I had many opportunities to test my lack of affection, and with consistent results until just a few months ago. Unfortunately I cannot share with you the brew that converted me unless you happen to be in Iowa. Downtown Des Moines' Exile Brewing has produced a beer called "Beatnik Sour" that is refreshing, complex and dry with sour notes that do not overwhelm or taste like lemon juice. Hard if not impossible to find outside the Hawkeye State, you'll just have to make the road trip.