Beer is ephemeral. That’s especially true during the waning days of summer with breweries flooding the market with harvest ales, fresh hop beers, festbier, even pumpkin and squash brews. Here today, gone tomorrow. And if you haven’t cruised past BJ’s Restaurant and Brewhouse for one of Aaron Stueck’s R&D beers, you don’t know what you’re missing. Take his Hop Harvest IPA (6.8% ABV, 50 IBUs) — pale straw in color with a slight haze and plenty of tight carbonation (which gives the beer a Pilsner-esque crispness). The nose is fresh, floral and vibrant, as is the taste: Ripe melon, lemongrass, orange blossom honey and a full hop presence in the back (Stueck says the recipe uses Strata, Loral and Jarrylo). It’s bright and clean, and the bitterness prickles your cheeks. And, as the beer warms, the malt shines through, sweet and delicious. If you hurry, you might snag a pint (word on the street is the BJ’s in Golden also has a keg). But even if it’s gone, Stueck has plenty more to try. Get ’em before they’re gone.