Buyer beware: Montgomery County has a problem with beer.

In store coolers and on sales floors across the county, lots of beer is slowly going bad. Budweiser is getting old. Coors is growing stale. Even Samuel Adams with its microbrew mystique is becoming as bitter as a can of Schlitz in the sun.

At Casa Veiga, a tiny convenience store blaring Latin pop music along Silver Spring's Flower Avenue, three 12-packs of Budweiser cool in the refrigerator case. But a look at the "born-on" date tattooed on the box shows the beer is three months past its recommended expiration.

"I'm sure every place around here you can find beer like that," said the store owner, Simon Ventura, who puts old beer on sale when he sees it. "When customers buy cheaper beer, they don't complain."

In any other jurisdiction, a private wholesaler likely would have exchanged Casa Veiga's old beer for fresh beer months ago as part of the lucrative territorial agreements worked out with Coors Brewing Co., Anheuser-Busch Cos. and other big breweries. But Montgomery treats beer like no other jurisdiction in the nation.

Montgomery holds an ironclad, state-approved monopoly on the beer wholesale market, which brings the county $45.5 million a year in gross receipts. The county's interest in beer dates to the end of Prohibition, when Montgomery's forefathers fretted about the Washington suburb becoming a bar-on-every-corner kind of place.

The monopoly has given Montgomery the power to dictate to beer-brewing giants what it will and will not do as a distributor, and as of now, it won't swap old beer for new. The refusal has prompted brewers and shop owners to unite in an effort to get Montgomery out of the beer business or at least make it act more like a private distributor. They have persuaded the state legislature to order Montgomery to pick up stale beer.

As part of negotiations to comply with state law, beer companies have offered to reimburse Montgomery for replacing its outdated products. But no agreement has been reached yet, as county officials wonder who will pay any additional labor costs.

"The truth is that if we add additional duties, we add additional costs," said Howard Cook, director of the county Department of Liquor Control.

The issue playing out in Montgomery is, in part, the product of a national marketing strategy by the big beer companies. Old beer -- as long as it is not ancient -- poses no public health risks. Rather, state regulators and others say, the notion of a beer's age is merely a advertising ploy by breweries to counter a microbrew industry that has made purity and freshness its hallmark.

"I can have beer in my fridge for six months, and it won't go bad," said Charles Ehart, director of the Maryland alcohol and tobacco tax unit that regulates the beer wholesale industry. "But there is corporate policy involved, so it's bad for the brewers."

Beer companies, however, say age is important. The freshness guidelines are set by what national breweries say is rigorous chemical testing and on-site taste tests conducted by employees. One beer company official said the roughly four-month shelf life is the point where an "extremely astute beer taster" would realize a change in the beer.

"Beer is a very delicate product," said Michael Jackson, a renowned British author on beer, who says pale American lagers are particularly vulnerable to aging. "It's not that it will harm you, but it certainly won't get better. And it will lose its hoppy delicacy and be susceptible to cardboardy, wet-papery or skunky flavors."

Some say Montgomery's refusal to switch beer comes down to the fact that it has become dependent on the revenue its alcohol business provides. The county is also the sole source for wine and hard liquor, and taken together with beer, the business is predicted to bring the county $14.7 million in pure profit for the fiscal year that ends this month.

In the county's 100,000-square-foot warehouse, cases of beer, wine and liquor reach to the ceiling. For an agency often criticized as a Soviet-style tribute to central planning, the Department of Liquor Control offers a wide variety of beers, including some from Vietnam, Peru and Thailand. Last spring, officials christened a new $1.5 million refrigerated room where keg beer is stored.

Gus Montes de Oca, chief of the county's wholesale operation, said the variety and the system used to ensure that customers receive fresh beer are proof the county cares about the beer business.

"We're here because of state law," said Montes de Oca, who spent 20 years in the private-sector liquor business. "That doesn't mean we don't give a damn."

But it is easy to find expired beer on store shelves, partly because brewers can't trade wholesale beer for retail beer because of state law. In November, Anheuser-Busch was caught doing that and narrowly avoided a fine.

A recent tour of five corner convenience stores in and around Silver Spring found four with at least two six-packs that had gone beyond their freshness dates.

At Seminary Beer & Wine on Georgia Avenue just inside the Capital Beltway, two 12-packs of Busch and two 12-packs of Coors had expired. Benjamin Kamjou, the store manager, says he keeps close track of Samuel Adams and other slow-moving brands but had overlooked the major products.

"If it's old, too bad -- you eat the cost," Kamjou said. "As long as you keep it cold, it may stay good for a long time. But it's no longer fresh."

Dave Taylor, head of corporate communications at Coors in Golden, Colo., said private distributors that left old beer on the shelves would be censured and perhaps fired.

"It is not pleasing news," Taylor said after hearing about the out-of-date Coors at Seminary. "We do audits and have agreements with distributors that make sure that doesn't happen. In Montgomery, there are larger challenges there."