The brewery has partnered with Alcoa Inc., the world's largest aluminum maker, to produce aluminum bottles that Alcoa officials said keep beer colder for as much as 50 minutes longer.

About 20,000 cases of the new aluminum bottles of beer are en route to as many as 28 states and should be on shelves this week, Alcoa and Pittsburgh Brewing said Tuesday.

The bottles have three times the aluminum of a typical beer can. That gives them superior insulation, Alcoa spokesman Kevin Lowery said.

It's not the first time Alcoa has teamed up with the local brewery to put out a new product. In 1962, the two put the first pull-tab beer cans on shelves, freeing beer drinkers of the need to carry openers with them.

"We think it's much better than a can and as good or better than glass," said Joe Piccirilli, vice chairman of Pittsburgh Brewing, of the new bottles. "There's no doubt in my mind that this has the same potential as the pull tab we did with Alcoa."

Pittsburgh Brewing wants to expand sales. But the aluminum bottle may be more important to Alcoa. The aluminum giant wants to win back a share of the market it lost to beer bottles — both glass and plastic, which are now common at sporting events nationwide.

Bottles have gained ground over the past decade. About 40 percent of all beer consumed now comes in cans, 43 percent in bottles and 8 percent from the tap, according to the Beer Institute, which tracks industry trends.

Plastic bottles make up only 0.5 percent of all beer sales, according to the Beer Institute.

But having aluminum bottles at sporting events would introduce the product to thousands, who might buy a case for home.

Pittsburgh Brewing said it won't drop glass bottles or cans from production.

Some people say they can taste the difference between beer in cans and bottles.

Lew Bryson, an author of two books on breweries, said those complaints are psychological, since the aluminum is coated. But, he said, there may be a lingering taste when the seal of an aluminum can is broken.

The aluminum bottle could eliminate that, he said.

One microbrewery based in Missoula, Mont., has been using aluminum bottles.

Heineken released a limited-edition aluminum bottle last year.

Aluminum bottles also have proven successful for a few breweries in Japan, but Iron City is the first brand in North America to ship the bottles nationally, company officials said.

Alcoa and brewery officials say the biggest selling point of the bottle may be its appearance.

Bryson agreed, and said plastic bottles have also been a problem at some bottling plants because they are lighter than glass and can become jumbled.

But he said the advantages may not outweigh the price.

"It seems a bit like an answer in search of a question," he said.

Pittsburgh Brewing said aluminum bottles cost more than twice as much as glass — about a nickel more per beer — but Alcoa and the brewery said the cost will come down if other beer companies follow suit.

Pittsburgh Brewing, which sells about 6 million cases of beer annually, has opened a six-figure marketing campaign to try to make the idea stick.