They talk about the altitude of mountains in Jamaica. They talk of searching for the right shape and color of coffee cups. They talk of the natural properties of bat manure. Most emphatically, they talk of people, like the one-shot espresso guy, who comes every day and never sits down.

Five years ago, Estelle O'Connor, Carla Bravo Wing and Yvonne Nicholson knew little about the intricacies of coffee production, coffee brewing and coffee serving.

Now, as they sit around a marble-top table in the rear of their Washington store, Roasters on the Hill, they are eager to share everything they have learned about the coffee business and store ownership.

"We control our own product. We are not at the mercy of the roaster," said Nicholson, glancing toward a parade of burlap bags with beans ready to be roasted, a ritual that begins nightly around 6:30 and continues into the wee hours.

The machine, standing guard in the window along Seventh Street SE, down the street from Capitol Hill's landmark Eastern Market, looks like a belching red furnace and has become a point of conversation for passersby. "They have been guessing a popcorn machine, a peanut roaster, a chicken roaster, a gambling machine," O'Connor said.

Roasters on the Hill, which begins its third year of business today, was the first specialty coffee roaster and espresso bar in the District. With the tantalizing aroma of coffee wafting through almost all shopping malls now, it is clear that the founders of Roasters were among many retailers who have recognized that gourmet coffees are a booming part of the $6.5 billion coffee industry.

At the store they roast more than 4,500 pounds of beans and sell some 12,000 cups a month. Forty-four percent of their business is cups of coffee and pastries; 47 percent is unbrewed coffee.

On opening day they had 10 coffees roasted; now they have 53 in their inventory. The owners said business increased by 61 percent in the last year, although they would not reveal their revenue.

"We are doing a monthly business of 20 times the amount than when we started. We have reached our goal for the second year and are getting ready to make that turn to profitability this year," said Wing, the operating manager, who ran the store alone for nearly 18 months. The other owners pitch in on weekends and during vacations.

The store has 10 part-time employees, including one designated for roasting-only duties. Their coffee club, a discount organization for Roasters' repeat buyers who also receive a quarterly newsletter, has a membership of 1,600 people.

O'Connor, 36, a flight attendant for 16 years who continues to work for Trans World Airlines, proposed a coffee bar to her two friends after an acquaintance of hers opened an identical business in Chicago.

She enlisted Wing, 40, who was directing her own public relations company and had been a publicist for a country-music station, and a third friend, Nicholson, 38, then a purchasing supervisor for Marriott Corp.

"We saw how the market was going, how people were getting out of the alcohol bar stages," O'Connor said.

The over-35 crowd was returning to coffee, this time with disposable income and fine-tuned tastes. "People who had left coffee, who had left cigarettes -- for health reasons -- were now coming back to coffee, not for the supermarket blends but for gourmet coffees," Wing said.

A study financed by the National Coffee Association of USA Inc. reported that daily coffee consumption is up 1.1 percent from last year, at 1.75 cups a person, after falling from the highs of the 1960s and holding steady for about the last five years.

The Specialty Coffee Association of America reports that sales of gourmet coffee are growing, representing 19 percent of all coffee sold in 1990.

The association predicts that by 1994 gourmet coffee will account for nearly a third of all U.S. coffee sales.

The founders of Roasters on the Hill knew location was the key to a coffee store and that they wanted an area with a mix of people, jobs and schedules. "We are very interested in being a people-oriented place, sort of like 'Cheers' without the alcohol," O'Connor said.

With Union Station as a departure point, they started walking. They studied census data. "When we hit this location, we knew it was perfect," Nicholson said. "The actual building was under construction. We saw the traffic, we saw the energy. There were plans for more office space, and, most importantly, it was a strong residential neighborhood."

With all their enthusiasm about coffee, they still had to learn the nuts and bolts of financing and marketing. The complexities of coffee and setting up a business that combined several aspects of retailing hit O'Connor and Wing one day at a meeting after they had produced what they thought was a respectable business plan.

A potential investor wanted to know the individual cost of the coffee, the sugar, the cream, the cup and the stirrer in each cup of coffee. Price it out, they were advised. And, how many of those cups will you sell each hour? They did the coffee equivalent of a nose count. They sat outside seven convenience stores all over the region and counted the cups that came out in hands and brown bags.

After rejections from four investors, the group put together a package of $160,000 from the First National Bank of Maryland, the District's Office of Business and Economic Development and their own pockets.

One drawback once they got started, the owners recalled, was getting specific breakdowns of costs from the construction supervisors. "Some were not taking us seriously," Wing said. "They thought we were bored housewives."

Their store is located at 666 Pennsylvania Ave. SE in the award-winning Stanton Development Corp. project on the site of an old Kresge discount store. It is 700 square feet, with a red Italian tile bar that seats seven, a side bar that seats five and an outdoor cafe with 30 seats.

The owners of Roasters on the Hill said their store is one of two African-American-owned coffee businesses in the nation. There are about 10,000 retail coffee stores in the country, according to the specialty coffee association.

To underscore their uniqueness as a black business, the women set up a booth at the annual Congressional Black Caucus weekend this fall and invited representatives of the Kenyan and Guatemalan coffee industries to promote their coffees.

For their own education and as a store service, the owners have experimented with blending, spending seven months to get the right espresso for themselves and developing signature blends for individuals and businesses.

Their coffees range in price from $6.75 a pound for Colombo Supremo and French Roast to $27 a pound for Jamaican Blue Mountain. The owners are planning to expand into the wholesale market, gain certification as an organic roaster and devise more signature blends.

Washingtonians have staked out their own preferences.

"They ask a lot of questions about where the coffee is from," Wing said. "We directed those customers to our organic coffees, which are the only politically correct ones environmentally. As I told them, if you want all your coffee from countries that are politically correct, you would have no coffee."

The clientele also demands a number of decaffeinated blends and Roasters on the Hill has increased its selection to eight regular and seven flavored beans.

"The market is experimental too. They will definitely try a new bean," Nicholson said. Right now customers are enthusiastic about Celebes Kollossi, an Indonesian coffee that costs $13.50 a pound.

And as further evidence of the strong market for gourmet coffee here, Washington has a healthy share of bean and equipment stores, coffee bars and a second on-premise specialty roaster, the Java House on Q Street NW.

Then there's the link between bat manure and Washington's drinking habits. For years one of the most prized, and often scarce, coffees has been Jamaican Blue Mountain. There is always a scramble for it because 90 percent is sent to Japan, O'Connor said.

Few of the beans are exported unroasted, which is how they arrive at Roasters from a 15-acre farm in the Blue Mountain Ridge of Jamaica, more then 4,000 feet above sea level.

"The clouds hang in there and the moisture makes for a nice bean," Nicholson said.

The farmer who grows the coffee and two workers go into caves all over Jamaica, carrying torches so the bats won't attack them. They shovel out the manure to use as fertilizer.

"It is very potent and very strong," Wing said.