MADISON, Wis. (AP) — About the only thing Kevin Flynn enjoys more than drinking his home-brewed beer is sharing it with fellow beer club members at festivals and tasting competitions. So Flynn and his buddies were shocked to discover that Wisconsin law prohibits sharing homemade suds anywhere outside the brewer's home.

The law could "pretty much be the end of competitions in Wisconsin," he lamented. "At least legal ones."

An explosion of interest in home brewing is forcing lawmakers across the country to review long-forgotten alcohol laws, some of which date back to Prohibition. Although the old rules have rarely been enforced, beer enthusiasts fear they could criminalize the rapidly growing hobby and kill scores of annual tasting events that bring tourists to small towns and cities.

In Wisconsin, Flynn and other home brewers may soon be off the hook. The state Legislature last week passed a bill to allow them to transport homemade beer and wine and to share it with other adults. Brewers will still not be permitted to sell anything they make, and they will remain exempt from permit requirements and taxes.

The proposal now heads to Gov. Scott Walker, who plans to sign it into law.

At least 17 states have ambiguous laws on whether home brewers can transport beer or wine outside the home, according to the American Homebrewers Association in Boulder, Colo.

The patchwork of rules can be frustrating for hobbyists who would prefer to spend their time exchanging recipes for pale ale or rhapsodizing about different varieties of hops, barley and yeast.

Some states — including Georgia and South Carolina — have restrictions similar to Wisconsin's. In Kansas and Minnesota, home brewers can only make beverages for themselves or family members. Other states permit homemade beer and wine to be consumed by guests, too, as in Arizona, Hawaii, Idaho and Illinois.

A few states have been slow to accommodate the trend. Utah just legalized home brewing in 2009, and Oklahoma followed in 2010. Mississippi and Alabama are the only states that still forbid it.

Dan Grady of the Wisconsin Homebrewers Alliance, who led the legislative effort to revise Wisconsin's law, said beer-makers need to be watchful in case states try to use the issue to generate money for their tight budgets.

"States are under enormous pressure. It's a revenue issue," he said. "Everything is on the table these days."

Gary Glass, director of the home brewers association, said it's a balancing act when considering whether to pursue a change in the law.

"The question becomes, at what point does a home brewing community want to take on having the law changed if it's not really having an impact to what they're doing?"

Glass, who organizes the group's popular national conference, said he's had trouble securing a venue in states with vague home brewing laws. The conference, which changes its location annually, brings in $500,000 to local economies.

A grassroots reform effort succeeded last year in Oregon, where the law had been similar to Wisconsin's. Glass, who helped draft Wisconsin's bill, said the legislation's demise would have set a bad precedent for home brewing.

"In this economy, you're stifling an industry that's growing," he said. "It sounds like a bad move."

More than ever, people with little or no experience brewing beer or other fermented beverages are investing in kits and ingredients to make their own. The hobby has expanded into a vibrant beer culture, with brewers freely sharing their concoctions among neighbors and friends and in clubs and competitions.

Last year, there were 411 beer competitions sanctioned by the home brewers association and the Beer Judge Certification Program. That's up from fewer than 100 in the early 1990s.

"Back in the day, everybody thought home brewing would just be what your grandfather would do," said Jason Heindel, president of the Beer Barons of Milwaukee Cooperative.

Home brewing has also helped invigorate the booming craft brewing industry. And it's generated a cottage industry of its own. An annual survey of brewing supply shops around the country showed an increase in sales for beginner brewing kits, according to the home brewing association.

Home brewing was illegal in the United States until 1978, when the federal government lifted Prohibition-era restrictions on making alcohol in the home. The revised law allowed homemade beer and wine to be offered at tasting competitions but also left most alcohol regulations up to individual states. So many states have their own home-brewing rules that supersede federal policies.

In Wisconsin last year, brewers were caught off guard when the state Department of Revenue ruled that it was illegal for home brewers to share beer outside the home. The decision came after Racine officials inquired about a contest known as the Schooner Home Brew Competition.

After the department's announcement, organizers quietly moved the contest, one of the state's largest, from Racine to nearby Union Grove. But they didn't advertise it because they feared possible fines.

Grady said home brewers in other states can learn from Wisconsin.

"Home brewers need to look at their state law, because they might be just as ambiguous as Wisconsin," he said. "And if there's ambiguity, they need to contact their lawmakers to get them clarified, much like we're doing here."