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“Fun guys”? Fungi? Get it? Ahh, nevermind.

You might have spotted beers by Denmark’s one-man Mikkeller in all their graphic-designed glory and wondered about these anomalous brews, specifically about why you should part with $6 or $7 for a single 12 oz. bottle. I can’t vouch for the prices — though good beer is expensive, and maybe Denmark’s currency has some stranglehold on the dollar that I’m unaware of. Mikkeller’s beers are unequivocally interesting, usually delicious, and sometimes worth the price tag. But their newly announced “educational” yeast series sounds like something to keep an eye on.

The company will brew one prototype beer, an 8% abv pale ale, and subject different batches of it to five different yeast strains: lager, U.S. ale, Belgian ale, German wheat, and brettanomyces (the prototypical “wild,” or naturally occurring, yeast). Each batch will be bottled separately in 12 oz. bottles. I imagine the differences between the batches will be enormous, highlighting what is probably the most ignored ingredient in beer: yeast. (OK, actually water gets even less credit, but that’s another post.) We think of malt and hops as the building blocks, and by mass they comprise nearly all of beer’s solid ingredients. If you were baking bread, malts would be the flour and hops would be the flavor stuff, caraway seeds and whatnot.

But different yeast do more than just eat sugar and burp out alcohol — a.k.a. fermentation. During this process they emit chemical byproducts (esters and phenols) that contribute aroma and flavor in ways hops and malt cannot. Yeast used in German wheat beers give off notes of banana and clove. Belgian yeasts emit their signature spicy aromas. Brettanomyces (our friend “Brett”) is appropriately wild and unpredictable, with weirdo smells ranging from mold to barnyard to sweaty socks.

I love Stone Cali-Belgique IPA, my #1 beer of 2009, for its similar illustration of the powers of yeast. The beer is just plain Stone IPA, except subjected to a Belgian yeast strain instead of Old Glory, and the result is a hoppy American IPA with exotic fruit flavors superimposed on it. Compare the two Stones side-by-side — or try two of these Mikkellers when they come out — and thank your fungal friends for making beer what it is.