By Joe Sixpack
Posted on June 5, 2009 on Joe Sixpack

ASSUMING the world's scientists have this whole global warming thing right, I figure we've got two years, three at the most, till we're all wearing SPF 100 and it's crocodiles, not moose, that Sarah Palin is hunting up there in Alaska.

Thankfully, the world's beer makers have already sprung into action.

Greenhouse brew, aka summer beer, is the most popular seasonal of the year. Hefeweizen, fruit beer, blond ale, witbier, helles, Kolsch and pilsner - these are all classic summer styles, brewed to accomplish the No. 1 goal of beer: refreshment.

Typically light in color and body, one easy quaff of these beers will clear the sweat from an afternoon behind the lawnmower, and a sixpack will have you sleeping with the air conditioning on low.

Here's three notable styles this summer.

Watermelon beer

Don't laugh - the few I've tasted are surprisingly cooling and fun, bringing to mind a picnic in the shade on a lazy afternoon. (Just remember to spit out the seeds!)

The most widely distributed is Hell or High Watermelon Wheat from 21st Amendment in San Francisco, available locally in cans.

Brewer Shaun O'Sullivan said the idea for the beer came from an old homebrew recipe of his co-founder, Nico Freccia. "I thought it was ridiculous at first," said O'Sullivan. "C'mon, watermelon beer? It was the same reaction anyone would've had."

The secret is in the ale's fermentation, which leaves behind little residual sugar. It starts out with a fruity aroma, with only a touch of sweetness, and finishes dry, so you're eager to take another sip.

There aren't many watermelon beers on the shelves, yet, but look also for Thomas Hooker's More Than A Mouthful Watermelon Ale (Connecticut), with an even stronger melon aroma, and draft Watermelon Lager from Roy Pitz (Chambersburg, Pa.).

Hefeweizen

American-brewed hefes are notoriously uneven, rarely matching the fresh, aromatic quality of the original Bavarians. Many beer experts simply call ours "American wheat ales" because they bear little resemblance to the likes of classics from Germany's Paulaner and Schneider breweries.

Sierra Nevada's new offering, Kellerweis, may be the closest to the real thing.

Its brewers believe the trick is open fermentation, a process that is the hygiene opposite of the typical sealed and sanitized brewhouse. In this traditional method, the beer bubbles away in large, uncovered vats or tubs, protected from bacterial infection beneath its thick mass of foam.

Sierra Nevada says the process gives yeast - which is the backbone of any hefeweizen - the necessary room "to build layers of flavors and aroma that would otherwise be impossible."

Kellerweis is soft and mellow, with the appetizing banana and citrus aromas that give the style its reputation in Munich as a breakfast beer. Forget orange juice; grab a glass of this cloudy, unfiltered ale when the thermometer hits 90 at 9 a.m.

Double white

Witbier, or white beer, had been extinct for a decade in the mid-1960s when a Belgian milkman-turned-brewer named Pierre Celis revived the cool, spicy, famously cloudy wheat beer once made on farms east of Brussels. That beer became Hoegaarden White, and it spawned 100 lemon-topped sons, from American-made Celis White to Coors-made Blue Moon.

With witbier gone mainstream, a growing number of breweries are amping up the style with more malt to create double white. It's just as hazy with a pinch of spice and a wallop of alcohol that will lay you out on your chaise lounge.

The newest, just in time for Father's Day, is Honey Do Wit (get it?) from Iron Hill Brewery & Restaurant. Flavored with orange peel, coriander and orange blossom honey, it's sweet, a bit fruity, tremendously refreshing and decidedly strong at 9.5 percent alcohol.

Other notable double whites are bottled by Great Divide (Colorado), Southampton Ales & Lagers (New York), River Horse (New Jersey) and Boston Beer (Massachusetts).

Here's a sixpack of other summer newbies:

Widmer Drifter Pale Ale (Oregon): Very easy drinking with assertive, citruslike Summit hops.

Weyerbacher Zotten (Easton): A hoppy Belgian pale ale, lower in alcohol than the brewery's famously "big" beers. Spicy and full flavored, ideal for the beach.

Harpoon UFO White Ale (Massachusetts): An unfiltered wheat made with orange peel, coriander and the relatively new Apollo hops variety.

Magic Hat Wacko! (Vermont): A full-flavored oddball from Vermont, made with beet sugar.

Nakhon (Thailand): A sweet pilsner brewed with jasmine rice.

Yards Saison (Philadelphia): Yards has redesigned one of its oldest styles, creating a spicier, beautifully refreshing ale made with pilsner malt and Belgian candy sugar. Pairs well with barbecue.

"Joe Sixpack" by Don Russell appears weekly in Big Fat Friday. For more on the beer scene in Philly and beyond, visit www.joesixpack.net. Send e-mail to joesixpack@phillynews.com.