Chicagoans have lots of great locally brewed summer session beers to choose from—the kind you feel like crushing in quantity when it stays warm all night and the porches and backyards of the city sing their songs. My favorites, just off the top of my head, include Metropolitan's Zwickel Flywheel, Half Acre's Pony Pilsner, Two Brothers' Sidekick Extra Pale Ale, Church Street's Heavenly Helles, and Off Color's Troublesome. (I suspect that Off Color's new Berliner weisse, Fierce, will join them, but when I wrote this I wasn't sufficiently acquainted with it.) Charging into the peloton, if not definitively into the lead, is Geneva's Penrose Brewing, launched this spring by Goose Island veterans Eric Hobbs and Tom Korder—their Proto Gradus (that's "grah-dus," not "gray-dus") is a 4 percent Belgian-style single with a fruity, floral, yeast-forward aroma, a surprisingly silky texture, and a clean, dry finish whose cool minerality feels like holding a river pebble in your mouth. Orange blossom, mango, and peach tangle with delicate tartness and green-banana astringency, both of which play well with the honeyed-biscuit malts. The Penrose folks plan to use Proto Gradus as the base for their sour program, and they've already released a version fermented for six weeks in a cabernet barrel—one of 22 beers served at their tap room in its first two months. By the time you read this, fine Penrose beverages will be aging in 30 wine barrels and 26 bourbon barrels, and any day now the brewery should start shipping its first four-packs of 12-ounce bottles, filled with Proto Gradus and P-2 Belgian-inspired pale ale.