THROUGHOUT the centuries of experimentation that followed the brewing of the first cup of coffee, it was generally agreed the best coffee thrives only in the zone between the Tropic of Cancer and Tropic of Capricorn, is grown at the highest allowable altitude and is exposed to direct sunlight only part of the day.

But there are almost unlimited varieties of coffee with different body, flavor and aroma available in the world, as the beans tend to take on the characteristics of the soil where grown. For instance, coffee grown in some areas of Southeast Asia where much rubber was also harvested, manages to take on a little of that Goodyear flavor.

There is a growing body of consumers, though, who are battered by coffee prices manipulated like Iranian oil and looking for better quality in the fewer cups they are drinking. The top-shelf brands which attract this group cost considerably more than the vacuum-packed varieties available at supermarkets. Yet their purchase can be considered a good investment, if not indulgence, by those who become addicted to the rich flavor and aromatic joys of coffees fresh roasted and ground at the counter with such exotic names as Sumatra, Java, Killimanjaro and Antiguq.

For the unitiated, there are no simple rules to follow in the search for a quality coffee of memorable flavor. Experimentation is the best way to settle on a fresh-roasted blend. The first time out pick a standard blend, one the store owner or manager considers the most popular. This is uaually a house blend. (Keep in mind that there are only a few local wholesale suppliers so the house blend -- regardless of the name -- may be the same in many cases.) A house blend probably won't be too bitter or too strong.

The color of the bean can be deceiving. Before roasting, most look identical. Gradations of brown color are imparted in the roasting. A common mistake is to think that a darker and shinier bean has more flavor and makes a fuller-bodied coffee. Each variety of bean, although roasted identically, will have its own taste. Add to this the roasting of the same type of bean for different lengths of time and at different temperatures, and the combinations become almost limitless. There are only three stores in the area that attempt roasting: M. E. Swing, The Coffee Bean and Georgetown Coffee Tea and Spice.

Espresso blends, French roasts, Italian roasts and Vienna roasts are blends which you may wish to sample. These are all roasted longer for stronger flavor. After trying a good house blend, you can begin to experiment with the finer points and learn the meaning of such terms as full-body, wineyness, aromatic and nuttiness.

Brazils or Santos (the port from which they're shipped) are the Saudi crude of the coffee cartel. They are a good base coffee for blending. Milds, the name of all other coffees produced in the Americas, are just that: Milder, more flavorful. The best of them are Guatamalens, Jamaica mountain, Columbian and Antiguans. Each has a distinct flavor.

Jamaican blue mountain beans are special and hard to come by right now. Many stores are selling what is called Jamaican Mountain Type. It is not quite the same, but still good.

The United States is a relative newcomer to coffee growing, but Hawaiian Kona is considered a superior coffee on its own without blending. As with most things with the American label it is priced in the upper half of the price spectrum.

Southeast Asian coffees are similar to Brazilian beans to a degree, though somewhat stronger. They are almost always blended with others for taste, though some consider Sumatra superior on its own.

There are two general classifications to coffee, arabicas and robustas. Arabicas are the grandaddys of all coffees. You'll probably never run into robustas in gourmet coffee stores. They are the prime crops of countries such as Zaire and Uganda. While they are considered extremely bitter, they are the staple of dried and soluble coffees as the flavor holds up under processing.

Area stores also offer flavored coffees such as Vienna roast, which has been blended with bits of cinnamon. Other flavors include rum, brandy, Swiss chocolate, chocolate almond and cherry. Decaffinated gourmet coffees are available as well, including a decaffeinted espresso blend. Some stores offer decaffeinated benas that have gone through a water process and are said to be free of chemicals. The caffine has been washed out of the bean through high pressure steam rather than the traditional method of soaking the bean in benzene and washing it out with chlorinated water. Ask if a decaffinated coffee is made by the water process. It's more expensive but the taste will be superior.

Listed below are a number of coffee shops and sellers in the Washington area. Prices quoted are from this week, but coffee, like gasoline, tends to fluctuate upward as of late.

M. E. Swing, 1013 E. St NW: The most established coffee roaster and retailer in the Washington area, Swings has been blending and roasting all of the coffee beans they sell since 1916. Their house blend, "Mesco," is a Washington standby. Swings prices range on the lower end of the scale -- Mesco is $3.70 a pound, Kona is $5.25 a pound and the Mocca Java blend runs $3.80 per pound. Prices for other coffees are in the $4-a pound range.

The Coffee Bean, 217 King St., Alexandria: These home-roasted beans are available in 27 different varieties. Prices vary from $4.75 a pound for the house blend to $5.45 for Mocca Java. Decaffeinated brands are a little more expensive.

Georgetown Coffee Tea and Spice, 1328 Wisconsin Ave. NW: The 32 selections offered are roasted on the premises. Prices range from $3.25 for the house blend to $7.99 per pound for the Jamaican Blue mountain, which is the most expensive available now. Prices for most of their coffees, however, are in the $4 to $5 pound range.

The Bean Bag, 10400 Georgetwon Rd., Bethesda and Lake Forest Mall, Gaithersburg: Here, too 27 varieties are offered and prices range from $4.69 for the house blend to $5.79 for Sumatra. They also have 7 different decaffinated brands and a number of flavored coffees.

The Perfect Cup-of-Coffee, Tea and Cocoa; White Flint Mall, Rockville: They offer 33 varieties of coffee and blends. Prices range from $5.25 a pound for the house blend to $6 for decaffinated espresso. All decaffinated brands are treated with the water process.

The Coffee Mill, 8344 Georgia Ave., Silver Spring: Fifty different coffees and blends are available, including flavored and decaffinated brands. Prices are in the $4 to $6 per pound range.

Coffee, Tea and Spice, Columbia Mall: Prices are about to go up on the 32 varieties offered. This week on sale the house brand was $4.10, decaffinated $5.15 and $4.55 per pound for espresso.

Carol & Co., 1627 Connecticut Ave. NW: Their main business is selling coffee and coffee machines, however, they sell a number of other kitchen items as well. Carol's has 14 different types and blends of coffee including one decaffinated and one flavored. The prices are either $4.89 or $4.99 per pound for all coffees. It was the only store we found which sold chicory in bulk ($1.89 per pound).

The following stores, although not specifically coffee shops, sell a variety of coffee beans and blends:

Gourmet Touch, Montgomery Mall, Rockville: Sixteen selections including some flavored and decaffinated brands are offered. The house blend is $5.25 per pound and the most expensive decaffinated blend is $6.25 a pound.

World Imports, Tysons' Corner, Falls Church: A wide selection of coffees and blends range from $4 to $6 per pound.

Old World Market, Foxhall Mall, 3301 New Mexico Ave.; 8125 Wisconsin Ave., Bethesda: Over 20 different types of coffee are sold including flavored and decaffinated brands. Price range from $4 to $6 per pound.

Bradley Food and Beverage, Bradley Shopping Center, 6909 Arlington Rd., Arlington: Twenty varieties of coffee are offered also in the $4 to $6 range.

Larimer's Market, 1727 Connecticut Ave. NW: Larimer's sells about 20 varieties of coffee in addition to 50 different canned varieties. Their house blend (Mesco) is $4.99 per pound.

Eagle Liquors, 3345 M St. NW: Thirty seven blends are sold including their house blend "Laddies Moustache" ($4.15 per pound). Mocca Java is $5.85 per pound; the other are priced within that range.

Georgetown Wine and Cheese, 1413 Wisconsin Ave. NW: Their 25 varieties are on sale, so the current price is $4.19 per pound. Normally their coffees are $4.99 per pound.

Capitol Hill Wine and Cheese, 611 Pennsylvania Ave. SE: About 20 varieties are sold. The house blend is $4.99 a pound and others range between $5 and $6 per pound.

Charles of Capitol Hill, 3230 Wisconsin Ave. NW: Fourteen different varieties are offered from $4.98 per pound for the house blend to $5.69 for the decaffinated espresso. Prices have been averaged to avoid confusion.