DENVER -- For 10 years, organized labor has battled the Adolph Coors Co. with a boycott of the brewer's products.

The recently launched organizing drive by the Teamsters Union at the brewery has complicated that battle.

Since the demise in 1978 of a Brewery Workers Union local at Coors, based in Golden, Colo., the AFL-CIO has sponsored a highly public boycott of Coors products. The overall impact of the boycott has been difficult to gauge, but nearly all parties, including Coors, agree it has hurt the company during its recent market expansion into Midwestern, New England and Middle Atlantic states. In these areas, organized labor has aggressively promoted the boycott.

With the launch of their organizing drive, including an effort planned for the Elkton, Va., plant, the Teamsters have declared a moratorium on the boycott. Indeed, Teamster organizers are trying to win Coors workers to the union by arguing that only the unionization of the company will lift the onerous weight of the boycott from Coors.

However, with such a strategy, a clash between the Teamsters and the AFL-CIO may be looming. Officials of the giant labor federation have said the boycott will come off only when Coors allows a "climate for union organizing free of fear and intimidation."

Teamster officials and some rank-and-file workers at Coors say such a climate now exists at Coors.

With their Teamster hats and buttons, Ron Seaman and Gary Harnish are conspicuous union supporters who work at Coors. Yet they say the company has not retaliated against them or other pro-union workers.

Echoing the Teamsters' organizing strategy, the 39-year-old Harnish, a canning line operator, said, "I'm not anti-Coors; I like my job and this company has been good to me. But Coors has said there may only be two or three brewers left in 10 years and I feel our survival hinges on us being union and getting the boycott off."

Seaman, 44, a 14-year Coors veteran and a senior specialist in can packaging, agreed.

"Americans are a competitive people, but we can't compete with the roadblocks we're facing. We believe with a union label on it, Coors can compete on the East Coast," said Seaman, who worked for the unionized Latrobe Brewing Co. in Pennsylvania before coming to Coors.

Ben Steinman, executive editor of Beer Marketer's Insights, a West Nyack, N.Y., publication that tracks the beer industry, said "disappointing results in the second quarter indicate that Coors did not achieve the volume it had hoped for with the New York and New Jersey expansion."

Steinman said virtually every Coors promotional poster he has seen in New York is defaced with "Boycott Coors" stickers.

He said continuing union opposition to Coors in Michigan and Massachusetts may have contributed to declines in Coors shipments to those states for the first five months of this year, compared with the same period last year.

According to statistics compiled by Beer Marketer's Insights, Coors shipments to Michigan for the five-month period in 1987 were down 88,000 barrels from the level in 1986; in Massachusetts, the decline totaled 42,000 barrels from the previous year's period.

And, Steinman added, there were disturbing year-to-date declines in Coors shipments to Texas for the first five months of this year, and to California for the first four months.

Teamster officials say the fiercely competitive beer market means Coors can ill afford to have the boycott weighing the company down.

John Meadows, Coors' community relations director, said last week the company was doing better than it had expected in New York and New Jersey. Coors entered those huge markets this year.

Still, Meadows acknowledged that the boycott was hurting the company. "If you want to market and sell a product, you don't need any negatives," he said. He called the boycott "an aggravation, a block" that has put Coors on an unequal footing with other brewers.

"We'd prefer not to have the problem (the boycott), but the biggest threat to us is the industry itself," Meadows said, referring to sluggish growth overall in the U.S. beer industry.

Coors sold about 15.2 million barrels of beer last year, a gain of 3.4 percent from the year before.

Coors and Anheuser-Busch were the only major brewers to grow in volume in 1986. Last year, Coors ranked fifth among U.S. brewers, behind Busch, Miller, Stroh's and G. Heileman.

The Teamsters now represent 90 percent of the brewery workers in United States -- about 100,000 people, according to Charles Klare, national director of the Teamsters' Brewery and Soft Drink Workers Conference. Coors is the only nonunion major brewer in America.

Klare said his group has called off an organizing effort at Coors' new packaging facility in Elkton to concentrate on the company's core of 3,500 brewery production workers in Golden, Colo.

"The Coors workers haven't stampeded us, but their reaction has been very favorable," Klare said about the organizing drive that began in early July. "We have high hopes we'll have enough employes signed up to ask for recognition and if not get it, to ask for an election."

Vince Murphy, a Teamsters Brewery Conference organizer heading the drive at Coors' Colorado base, said the union hoped to have enough support among Coors workers within six months to petition for recognition from the company or an election.

Another player in the drama -- the AFL-CIO -- will undoubtedly be drafting its own strategy for dealing with the Teamsters' effort to organize Coors workers.

With its ongoing sponsorship of the boycott, the AFL-CIO cannot be ignored in any labor settlement with Coors.

"Our hand is on the boycott switch and that will continue until Coors settles its differences with the AFL-CIO," said Dave Sickler, a regional AFL-CIO director in Los Angeles and national director of the group's Coors Boycott Committee. "We will not drop the boycott until Coors allows workers to engage in organizing activities free from intimidation, threats and coercion."

Sickler said the AFL-CIO has periodically held talks with Coors about ending the boycott.

"I can tell you this: The Teamsters have nothing to do with our discussions with Coors over what it takes to resolve the boycott."

"Coors has been trying to outrun us for 10 years. The Teamsters have just jumped the gun on us. They know Coors has been backed into a corner (by the boycott) and they smelled blood.

"We've got more faith in the intelligence of the workers at Coors," Sickler added. "They know that this has been an AFL-CIO boycott, not a Teamsters boycott, and that their job security ultimately rests with us."

Despite such bravura, the preemptive effort by the Teamsters to organize at Coors poses a dilemma for the AFL-CIO. To date, no union affiliated with the federation has stepped forward to organize Coors workers, although Sickler concedes that is a possibility, especially if the Teamsters near the goal of securing an election.

In such a competition, the AFL-CIO would face two powerful foes -- Coors and the Teamsters, whose stature is enhanced because they represent the overwhelming majority of workers in the brewing industry.

Teamster officials said they expect Anheuser-Busch's new Fort Collins brewery to sign with the union when the plant is up and running. Eleven other Busch breweries are affiliated with the Teamster