Two canine-themed breweries, including Frederick’s Flying Dog, battle for top dog of the zero IBU IPA.

International Arms Race Zero IBU IPA is a collaboration between two canine-themed breweries, Flying Dog Brewery in Frederick and BrewDog in Fraserburgh, Scotland. Actually, it’s more of a competition.

Both breweries agreed to do its own version of a hopless India pale ale (a veritable contradiction in terms, since the style is defined by its in-your-face hop content). Both would use alternative flavorings to duplicate the aroma and flavor of hops — bay leaves, elderflower, juniper berries, rosemary, spearmint, and lemon and orange peel. Each brewery, however, was free to vary the proportions in formulating its own recipe.

The two versions are entering the market now, in draft and 12-ounce bottles. Both measure 7.5 percent alcohol by volume. The Flying Dog version, however, is easily the drier of the two, with a savory quality from the bay leaves and rosemary (it would make a terrific marinade) and a tart, lemony backdrop that mimics the citrusy notes of Pacific Northwest hops. The beer almost succeeds in duplicating that prickly sensation that rises in the back of your throat as you down a well-hopped IPA.

BrewDog’s Zero IBU IPA is interesting in its own right, but sweeter, with the spearmint more dominant.

Matt Brophy, Flying Dog’s brewmaster, confesses that he cheated a bit, adding a minimal amount of hops. The federal government defines beer as a fermented grain beverage seasoned with hops, and would not have allowed Flying Dog to label the product “beer” in the complete absence of the bitter brewing herb. But it was a tiny amount, below the threshold of taste — one-tenth of a pound of Cascade hops diluted among 1,900 gallons.

“That wouldn’t be enough to bitter a homebrewer’s five-gallon batch,” says Brophy.

In August, the two breweries conducted blind taste-offs of their individual beers at five BrewDog-affiliated pubs in England and Scotland. Flying Dog emerged the winner, 3-2.

The war comes to the United States the third week in October at three pubs in the Baltimore-Washington area. You’ll be able to sample the hopless IPAs side-by-side and vote on your favorite at Max’s Taphouse in Baltimore on Oct. 15; at R.F.D. Washington on Oct. 16; and at the Frisco Taphouse & Brewery in Columbia on Oct. 17. In each case, the festivities begin at 6 p.m.

Flying Dog has also released the 2012 edition of Secret Stash, a hoppy pale ale made with mostly Maryland-grown ingredients, including Frederick County hops and locally harvested wheat. (A pinch of rye from Flying Dog’s malt providers renders the ale even drier.) If the stars align, Brophy says that he, BrewDog owner James Watt and the Frisco brew crew might team up for yet another collaborative beer. Details forthcoming.