If you want to sample Scott Metzger’s Old Bat Rastard brew, you will have to travel to San Antonio, sit down at his pub, Freetail Brewing Company, and order a frothy glass from the tap or ask for a half-gallon growler to go.

Pub owners like Mr. Metzger would love to sell their brews in retail stores, bars and restaurants, but state law prohibits it. So he and other owners have formed Texas Beer Freedom, a nonprofit lobbying organization, to push for legislation that would allow brewpubs to get their beer out beyond the bar.

But the small brewers have to overcome some opponents with big names and deep pockets: the powerful beer distribution lobby.

Mr. Metzger, who is also an economics lecturer at the University of Texas at San Antonio, said that while the locally brewed beer business is booming nationally, it is lagging in Texas, where the laws governing distribution are restrictive. As a result, he said, the state is losing out on tax revenue.