Early last year Bryan Deane Bertsch began making kombucha, a mildly alcoholic beverage of fermented tea, in the basement of a shared commercial kitchen on Marshall Avenue in St. Paul.

He found early success selling his wares in food co-ops and health food stores, but a national investigation by federal regulators that same year nearly shut him down. Regulators found that the alcohol content of kombucha exceeded 0.5 percent, making it an alcoholic beverage subject to the same regulations as beer, wine and spirits.

Many kombucha makers reformulated their recipes to reduce the alcohol content. Bertsch tried this, but found the results not to his liking. To continue making kombucha in the traditional way meant obtaining a brewer's license and classifying his basement space as a brewery.

This decision has created some hurdles for Bertsch. At 2.5 percent alcohol, Deane's Kombucha is too strong to be sold in food stores that don't hold a license for 3.2 percent beverages. This put the health food stores off-limits, cutting him off from a significant portion of his market.

As an alternative, Bertsch turned to the metro's growing number of specialty beer stores. He has received an enthusiastic reception from local beer fans, and Bertsch returns that enthusiasm. At in-store sampling events he is excited to see beer drinkers actually tasting his kombucha, taking the time to parse out all of the subtle, complex flavors.

Deane's Kombucha currently comes in four flavors: Original, Concord Grape, Ginger Matcha Cherry, and Ginger Honey. A fifth, Wisconsin Maple, will be released soon. Each one ferments for a week in oak barrels. The flavorings, including locally sourced honey, pressed ginger root and real fruit, are added in the bottle, causing a secondary fermentation that gives them a sparkling effervescence. Light, tart and fizzy, they are a refreshing counterpoint to the heat and humidity this summer has brought.

My favorite is Ginger Matcha Cherry. It's the tartest and funkiest of the bunch, with intense flavors of sour Montmorency cherries. Spicy ginger notes appear in the finish. Subtle barnyard notes, reminiscent of great Belgian lambics, provide an earthy background.

I was surprised how much I enjoyed the Ginger Honey flavor. Most ginger drinks have a spicy bite that is too strong for me. This one is smooth, fresh and sweet/tart. It has the flavor of ginger without the snap.

Original reveals more of the oak-barrel character than the others. White grape juice added in the bottle gives it a fruity, vinous flourish that complements the wood. If you're a fan of light, acidic white wines with a bit of oaky tannin, this one is for you.

Wisconsin Maple will be an outstanding addition to the lineup. Richer than the rest, it has ample maple flavor that counters the sour without being syrupy sweet. Underlying buttery flavors give it an appealing roundness.

Michael Agnew is a certified cicerone (beer-world version of sommelier) and owner of A Perfect Pint. He conducts private and corporate beer tasting events in the Twin Cities, and can be reached at michael@aperfectpint.net.