HARRISBURG — Pennsylvania’s beer distributors received the go-ahead Friday to sell brew by the 12-pack.

In an advisory opinion, lawyers for the Pennsylvania Liquor Control Board said distributors may sell 12-packs if the manufacturer designates them for sale as such.

Gov. Tom Wolf applauded the action, but a group representing small brewers was unhappy about it.

The opinion clarifies rules for the state’s brewers and beer distributors, which have had to sell beer mainly by the case or keg for decades.

“This is the biggest thing to happen to beer since 1933,” when Prohibition ended, said Pittsburgh distributor Frank Pistella, a vice president of the Pennsylvania Malt Beverage Distributors Association.

Pistella noted the price of specialty beers is now around $40 a case.

“That’s a big investment if you haven’t tried something,” he said.

“Now you can hand the (cashier) a $20 bill and get a little change back,” said Sean Casey, founder and owner of The Church Brew Works, a brew pub and microbrewery in Pittsburgh.

The governor said the advisory opinion is a step toward modernization that will enhance customer convenience and enable smaller breweries to better compete with larger companies.

But Brewers of Pennsylvania, which claims to represent small brewers who employ thousands of people, said the rules change will put them at a competitive disadvantage.

The group said the small breweries can produce 12-packs but lack the manufacturing and packaging capability to produce the 18-packs sold by the large out-of-state brewing companies. The group said it will work with legislators to resolve its concerns.

The opinion bars distributors from breaking up a case consisting of two 12-packs and selling them separately, so they may have to sell down their current inventory before they order containers designated for sale as 12-packs.

Beer can be purchased in six-packs and 12-packs at some Pennsylvania bars, convenience stores and supermarkets, but usually at higher prices than distributors charge.

In Philadelphia, the owner of beer distributor Franklin Beverage said he didn’t believe the news at first and called an attorney to make sure it was true.

“It obviously puts us in a more competitive environment. It gives the customers what they want,” Dan Mellbye said.