IT HAS AN all-malt base, a well-balanced body and a very hoppy nose. It is the new beer in town, one of the best in the country, some experts say, and it may be part of the beginning of a change in American brewing.

It is called New Amsterdam Amber Lager and it is the first microbrewery beer generally available in Washington. Microbreweries, the hot new thing in American beer, are brewing companies that produce less than 10,000 barrels of carefully crafted beer per year. (One barrel equals 31 gallons, or two kegs, or 13 cases of 12-ounce bottles, or 312 twelve-ounce glasses.)

The cutoff figure of 10,000 strikes some in the business as arbitrary and silly, but it seems to be sticking. In fact, some of the new breweries put out only a few hundred barrels a year; Anheuser Busch bottles more beer in a week than all the micros together have ever produced.

Americans drink a lot of beer--over 60 billion 12-ounce glasses each year--but most of what we drink tastes pretty much the same. American beers tend to be dry, light, thirst quenching--and very hard to tell apart.

The young entrepreneurs who run the new microbreweries are gambling that there is a market out there for other kinds of beers. They are brewing porters and stouts, pale ales and Vienna lagers, and opinion is divided over whether they are the catalysts in a beer revolution or a bunch of dreamers who are going to be around just about as long as it takes to open another bottle of Budweiser.

The movement to build small, local breweries got its beginning in 1965, when Fritz Maytag, the 28-year-old scion of the washing machine family, bought a part interest in the financially ailing Anchor Steam Brewing Co. The San Francisco brewery, which had been around since the late 1800s, was--and is--the only brewery in the country making steam beer, an American invention in which a beer made with a lager yeast is fermented at the higher temperatures usually reserved for ales.

Maytag bought out the other owners in 1969, and with a staff of five or six, set out to brew a high quality, locally distributed beer--and make money doing it.

Most people who knew brewing assumed he would fail; small local breweries had been closing at a steady clip for 40 years. But Maytag succeeded. Brewing only 600 barrels a year at first, he concentrated on quality and gathered a loyal following.

In 1971 he began producing bottled beer as well as draught. In 1973 the company first showed a profit. Today it sells 28,000 barrels a year in all the Western states and a few other places around the country, moving up in class from micro to regional and joining companies as small as the Spoetzl Brewery of Texas, which sells 30,000 barrels a year, and as large as Adolph Coors, which sells almost 12 million barrels a year in over 20 states.

Industry watchers credit Maytag's success with Anchor Steam kicking off the microbrewery boom. There are now nine operating microbreweries in the United States, according to Charlie Papazian, president of the American Homebrewers Association. Eight more are under construction, slated to begin production this year or next and at least a dozen more are in the planning stages, according to London-based beer authority Michael Jackson, who recently toured the United States exploring the microbrewery scene.

In a way, these breweries represent a return to brewing practices of a hundred years ago, said Jackson, who points out that the emergence of giant national breweries is a relatively recent phenomenon.

America was, before the Prohibition, home to 1,500 small, regional breweries. In 1935, one year after Repeal, 750 breweries had managed to reopen. Over 700 of those have closed or were absorbed by larger companies since then, according to the United States Brewing Association.

Today, says the USBA, there are only 44 separate brewing companies (including the new micros) in America, operating less than 100 separate breweries. Many regional breweries such as Lone Star of Texas and Rainier Brewery of Washington are owned by other, larger, breweries. Most of the 44 are regional companies, but the beer market is dominated by the giants at the top, whose annual sales account for over 80 percent of all the beer sold in this country.

The ranking at the top shifts often, but at the moment the order among the big boys in beer goes like this: Anheuser Busch, the biggest brewing concern in the world and the undisputed heavyweight champ in this country for 26 years, sold 59.1 million barrels last year; Miller, which Philip Morris bought in 1970, revamping the beer's image and marketing the hit, low-calorie beer Lite, sold 39.3 million barrels; Stroh, which shot up to third place in 1982 by buying Schlitz, the previous second runner-up, sold 22.9 million barrels; Heileman, which has become the country's fastest-growing regional brewer after buying 34 regional brands, sold 14.5 million barrels; Pabst, which recently bought the Olympian Brewing Co., sold 12.3 million barrels, and Coors, the market leader in many Western states, sold 11.9 million barrels.

All this leaves very little room for the microbreweries, which, so far, have managed to capture significantly less than 1 percent of the national market (imported beers account for about 4 percent). But it might be just room enough.

"My feeling is that the microbreweries are ahead of their time," said Jackson, author of "The World Guide to Beer," "but their time is coming very fast . . . I have seen, in the last 10 years, an inexorable change in American attitudes towards beer. The public is moving away from seeing it as a supermarket product, and towards seeing it as a gastronomic creation."

Maytag, of Anchor Steam fame, agreed, "Ten or 15 years ago, a lot of experts would tell you that the microbreweries were a flash in the pan; they were wrong. Something very amazing is happening here: an American culinary renaissance."

Maytag thinks the move is catching on because enough beer drinkers are tired of national brands that taste similar--and bland. Jackson ascribed the microbrewery vogue to a consumer belief that small is beautiful along with a growing desire to return to traditional ways of preparing food and drink.

Bob Holiday, editor and publisher of "The Brewer's Digest," had a different reason for what he predicts will be a successful movement. "Look, I go out every year and spend $250 on season's tickets for the Chicago Cubs. I know they aren't going to win maybe more than two or three games, but Chicago is my town and they are my team. A lot of people are going to buy local beers for the same reason," said Holiday.

Until recently, the microbrewery phenomenon was largely confined to the West. Prior to the marketing of New Amsterdam, the East Coast boasted only one, the William S. Newman Brewery Co. of Albany, N.Y., which sells a pale ale in the upstate area. That will change again soon when construction is completed in Virginia Beach of the Chesapeake Bay Brewery Co., which plans to start brewing its "Chesbay" lager beer by the end of September for marketing by the end of the year.

New Amsterdam became the first microbrewery beer sold in New York City last November. It has grown since then to become the first of its kind in Connecticut, New Jersey, and, as of July, Washington.

Over 28,000 cases have been sold so far, which is not bad for a beer that, at $17 a case wholesale, costs more than just about any other beer you can find. In Washington it is selling surprisingly well, according to the local distributor, International Distributing. The first shipment of 100 cases sold out immediately in June and last month's second hundred cases are mostly gone now. With another 200 cases on the way, you should very shortly be able to find the beer--if you're willing to pay more than you would for a bottle of Heineken, Moosehead or Beck's--in approximately 30 area liquor stores and 15 local restaurants.

Tasting the beer explains why the demand has outstripped the supply.

It is a full, rich lager, sort of similar to the English brew Watney's Red Barrel, but heavier hopped, with a spicy, slightly bitter bite to it. It is brewed using only water, barley malt and Cascade and Hallertauer hops. Unlike many American beers, it contains no corn, rice, sugars, or chemical additives or preservatives.

Those who have made it their pleasant business to taste and pronounce on beers (or at least those among them who have tasted New Amsterdam) have rated the beer highly. At the recent Great American Beer Festival, a mecca for serious students of brewing, 3,000 beer lovers ranked it fourth out of 48 contestants (placing ahead of it only Sierra Nevada Pale Ale, Sierra Nevada Porter and Anchor Porter, all highly regarded micro or small brewery beers.

Jackson called the beer very good, and added, in beer talk, "The key to its character is a very hoppy nose, rather more bitterness than one would find in most American beers, malty, and with a firm--but not full--body."

And Fritz Maytag adds, "It's one of the best. If I was in New York and I couldn't get one of my beers, I'd ask for his."

The beer got its beginning a few years ago when Matthew Reich, 32, a natural entrepreneur and a beer lover, got fed up with the blandness of American beers and decided to brew one he liked. Quitting his job as a circulation executive with Hearst magazines, he got 22 investors to put up $255,000 to found The Old New York Beer Co., hired veteran brewmaster Joseph Owades (the man who invented Gablinger, the first light beer, among other creations), and set out with him to invent a recipe. That done, he contracted with the old and highly respected West End Brewing Co., of Utica, N.Y. Reich used their facilities for the brewing and bottling, under Owades' supervision.

Today, sitting in his corporate headquarters, which turns out to be a dingy warehouse in a tough part of town, Reich is planning to open his own brewery in the East Village some time next year. He is optimistic, cheerful.

But, like the other microbrewers, he faces real problems. Maytag estimates that four microbreweries have failed so far and the rest are not making any money yet.

One veteran industry watcher dismissed them. "They don't have a chance. The economics of it are just against them. The big breweries make a better beer, cheaper."

Paul Camusi, of the Sierra Nevada Brewing Co., a West Coast microbrewery, agreed that times can be tough, "Being so small is very hard. The suppliers don't take you seriously; they charge you higher prices because you're not buying a lot, and it's very hard getting your beer distributed at all."

The pessimists are at least half right. Experts guess that some of the microbreweries, faced with higher costs per bottle than the big breweries, and unable to sell enough of their expensive products to defray those costs, will fold. But the same experts are betting that enough of the new companies will survive to make the microbreweries a permanent part of American beer drinking.