During these dog days of summer, when the thermometer cracks 90 degrees and the air is still and muggy, I look for something cold, crisp and easy to drink. Most mixed drinks are too high in alcohol, and even the most crisp white wine cannot quench my thirst. What really hits the spot is something light and spritzy with a snappy citrus flavor: the German-style beer called Berliner weisse.

This classic beer has been brewed in and around Germany’s capital of Berlin since the 15th century (and perhaps even earlier), yet it was relatively unknown in the U.S. until a few years ago. Once one of the most popular beers in Berlin, the style became nearly extinct in the 1970s but has slowly made a comeback thanks to American brewers and craft-beer drinkers.

A Berliner weisse is crisp like a lager but packs an acidic, tart punch that defines the style. Those characteristics are created by the bacteria lactobacillus, the same organism that gives yogurt tartness and adds the sour to sourdough. The bacteria consumes sugars to create the tart taste of lactic acid.

Lactobacillus, referred to as “lacto,” is naturally found on the husk of grains used to make beer, but it is usually killed off when beer is boiled during the brewing process.

In making Berliner weisses, however, brewers allow lacto to grow at warm temperatures of 90 to 120 degrees, and the resulting lactic acid creates a mouth-puckering tartness similar to sucking on a fresh lemon.

The sourness of a Berliner weisse is clean and bright, and devoid of the earthier qualities of many Belgian sour beers. Its refreshing quality comes from a combination of the citrus tartness; a smooth, almost creamy texture that results from a generous amount of wheat; and a dry, crisp finish. Add to that a Champagne-like carbonation that boosts its thirst-quenching qualities. The beer’s low alcohol by volume, typically less than 4 percent, also allows maximum drinkability.

It has become custom in Berlin to add a shot of sweet syrup — raspberry or woodruff, a perennial plant — to cut the tartness. But that tradition hasn’t carried over to the U.S., where craft-beer drinkers have embraced sour flavors. Folks who prefer less tartness could add a sweetened fruit syrup to create an almost sodalike drink.

Try these three American Berliner weisse beers, available at BevMart in Moiliili:

>> Off Color Brewing Fierce (12-ounce bottle, $3.99): With 3.8 percent alcohol by volume and a highly approachable tartness that won’t pucker your lips, this beer has a spritzy carbonation that fills it with wonderful bubbles. An aroma and flavor of freshly baked sourdough bread provides the perfect base for a mild lemony tartness that helps create a dry, snappy finish.

>> Evil Twin Brewing Nomader Weisse (12-ounce can, $3.99): Dominated by sharp, bright flavors reminiscent of umeboshi (Japanese pickled plums) and Meyer lemons, Nomader Weisse will delight any lemon and lime fan. At just 4 percent alcohol by volume, this beer is wonderfully refreshing.

>> Breakside Brewery Passion Fruit Sour (22-ounce bottle, $8.99): The addition of lilikoi is a home run with this beer. Vibrant tropical fruit flavors blend perfectly with the tart citrusy lactic acid. This 4 percent alcohol by volume offering is brewed in Portland, Ore., but tastes like paradise.

See Tim Golden’s blog, “Beer in Hawaii,” at beerinhawaii.com.