Redhook tests the fizz of new market - root beer. (Redhook Ale Brewery Inc.)

The next brew you see from Redhook Ale Brewery may not contain any alcohol -- it may be a root beer.

The Seattle-based microbrewer is testing two unnamed sodas, a root beer and a ginger ale, in its Woodinville pub.

Paul Shipman, Redhook's chief executive officer, has watched many small brewpub operations create their own sodas. Ever entrepreneurial, he wonders whether a new subcategory of regional soft drinks might catch on just the way microbrews did.

"It took me months to find a soda guy," Shipman said. "There's almost no regional or local soda companies anymore."

But microbreweries are dabbling in soda "throughout the industry," he …