Jason Wise's documentary follows four young men, including some San Franciscans, into the outer limits of wine knowledge. They're cramming for the Master Sommelier Exam, not unfairly described as the hardest test you've never heard of, whose takers tend to fail much more often than not. Of course even apprentice sommeliers probably know more about wine, and want to, than you ever will; part of what makes them into masters is knowing more than each other. Wives and girlfriends wait patiently on the sidelines as these fellas work up the unnerving capacity to sound like Rain Man rattling off suppositions and related factoids after every sip. It's not enough to know it smells like a freshly opened can of tennis balls; you must know when and where the balls were canned, and of course what brand they are. Yes, test prep like this tends to abstract the core wine-culture value of soul enlargement, and all aspirations to mastery have their dark side anyway. "Whatever you have inside you that's not good," one contestant confesses, "it will be drawn out by this exam." Wise's structure is essentially a reality-show configuration, with competitors persevering through the heat of their contest, but the movie carefully obeys the dress code of its presumptively classy milieu. Arrayed on a bed of upscale unintrusive jazz and decorated with interstitial stemware shatterings and slo-mo vineyard money shots, Somm glides by like so many wine-encyclopedia pages leafed through in an upscale tasting room: informative, appealing, but only as absorbable as your sobriety allows.