BRUSSELS, BELGIUM - At the Cantillon brewery, home to the Brussels Gueuze Museum in the city's Anderlecht district, visitors may find their glasses of kriek, framboise, lambic and gueuze are either half-empty or half-full. Along with the striking flavors of cherry and raspberry-flavored beers, optimists will savor knowing that for twenty years, Cantillon's master brewer Jean-Pierre Van Roy has maintained a commitment to traditional Belgian lambic brewing methods while around him, mass production techniques have all but delivered them a death blow.

Pessimists, on the other hand, may want to cry in their glasses. At the beginning of this century, dozens of micro-breweries like Cantillon were as much a part of urban life in Brussels as the tiny, café-like estaminets where the beers were served.

Today, only Cantillon and the mass-market Belle-Vue still brew beer within the city limits. A tour through the Gueuze Museum and Cantillon Brewery, will transport visitors to a decidedly different Brussels than the modern, Eurocratic one of the late twentieth-century. The Gueuze Museum and even Jean-Pierre Van Roy, too, recall an age when, as the Jacques Bhref lyric goes, "Brussels was brusseling" and the city's inhabitants were known for their unpretentious, bon vivant spirit.

Zwanze Guaranteed
Indeed, the warm and generous Van Roy is particularly proud to be a native bruxellois, a special distinction in a Belgium divided along language lines between French-speaking Walloons and the Dutch-speaking Flemish.

The brewer commonly shifts in mid-sentence from French to Dutch and adds colorful doses of the city's unique patois. A Gueuze Museum visit, Van Roy promises, guarantees zwanze--a bruxellois expression roughly comparable to "good times."

Nevertheless, with a production last year of well under 100,000 liters, Cantillon's unusual "artisanal" beers--Mr. Van Roy calls the more popular Belle-Vue's beers "industrial" by comparison--are decidedly an endangered species.

"To be the last one of anything is very difficult. The fight is getting to be too much for me," he says, though he is determined not to give up.

"I feel an immense responsibility to the next generation. I must transmit these traditions to the future."

A streak of evangelism, at least as far as lambic beer is concerned, runs through Jean-Pierre Van Roy. "People must be informed," he declares, and for Cantillon's newest markets, he has written a bottle-neck tag describing his artisanal beers and their history.

In 1978, he helped found the independent, nonprofit Brussels Gueuze Museum which conducts daily brewery tours. Last year, according to Jan Dorpmans, museum spokesman, more than 25,000 visitors passed through Cantillon.

A Beer From the Past
In lambic brewing, as Mr. Van Roy still practices it, a wheat and barley "wort" is fermented by exposure to atmospheric yeasts and other airborne microflora rather than with cultured yeasts. The technique is a throwback to the Middle Ages. Pitchers of what is likely lambic beer appear in Pieter Bruegel's 16th century depictions of festive Flemish peasants.

Aerobically-fermented beer was once the only kind available anywhere until the Industrial Revolution when brewers and scientists began to understand yeasts and how to control their effects. Only in Belgium are lambic beers still commercially brewed. Mass-market lambic brewers like Belle-Vue pasteurize, however, process and artificially sweeten their beers. Cantillon beers, by contrast, are never pasteurized and are so-called "living beers" which, like wines, continue to ferment after bottling.

If Belgium seems to occupy something like the place of an Australia in beer evolution--preserving strange species which have died out elsewhere--brewing history has hardly came to a halt here. Plain lambic typically has little carbonation and, for beer, an unexpected sourness. A century ago, an anonymous but inventive Brussels brewer discovered a method for blending young and aged lambics to make a sweeter, sparkling beer called gueuze (pronounced GERZ). This "revolutionary" beer probably took its name from the Gueux, 16th-century Flemish libertarians known by Belgians as revolutionaries.

Cantillon's own unique contributions to lambic types include, Bruocsella, a "grand cru" vintage-dated lambic (the name is Latin for Brussels), and vigneronne, a gueuze flavored with Italian white wine grapes.

More commonly, Mr. Van Roy also adds fresh cherry and raspberry mashes to sweeten his lambic. Those brews create respectively, kriek (pronounced "CREEK") and framboise. The cherries and raspberries in Cantillon beer are native to Schaarbeek, a Flemish community northeast of Brussels.

Lambic may be sold within weeks of brewing. For his gueuze, Mr. Van Roy uses a blend of one, two and three-year-old lambics. To make kriek or framboise, he adds the fruit to an 18 month-old lambic; the mixture is, in its turn, aged another six months. In the glass, kriek and framboise have a cheerful, celebratory lustre like rosé champagne.

Honey-colored lambic and gueuze resemble ordinary beer but, as with other wheat beers, they are redolent of citrus.

Old Habits Die Hard
The Cantillon brewery opened in 1900 when, as Jacques Bhref sang, Brussels "was brusseling" with the excitement of an imperial capital intoxicated by industrialization, Art Nouveau style and, of course, lambic beer.

The city population had swelled from 250,000 in 1865 to nearly 800,000 by century's end. Working men and women, crowded in slums, supported the many micro-breweries like Cantillon who delivered only to neighborhood pubs.

The 20th century, however, has taken its toll on Brussels in many ways. The imperial capital has become the so-called "Capital of Europe" as the administrative headquarters for the European Community. Art Nouveau architecture has fallen to be replaced by modernist glass towers and concrete apartment blocks. Likewise, an Americanization of drinking habits has seen lambic give way to lager as the Belgian beer of choice. In the 1958 World's Fair year for Brussels, according to Mr. Van Roy, Cantillon sold 275,000 liters of beer.

A former high school science teacher, Jean-Pierre Van Roy trained as a brewer in the early 1970s under his father-in-law Marcel Cantillon who died last April at 80 years old. The two-story brewery has specially-adapted clay roof tiles with slits that allow air to circulate and spark fermentation in the lambic beer. On the cave-like ground level, rows of enormous casks and stacks of bottles line nearly all the available space.

A science teacher's attention to detail and a quick wit lend Mr. Van Roy a spirited, garrulous character. His semi-annual public brewings, which begin at six o'clock in the morning, offer coffee and croissants to early-risers. Typical daily activity at the Cantillon brewery is less rambunctious and literally defines "family business."

On a recent morning, Mr. Van Roy, watched over a clattering bottling machine as it filled and corked green wine bottles with cherry-red kriek. At the far end of a conveyor belt deep inside the brewery, Mr. Van Roy's wife, Claude, and son, Jean, capped, labeled and stacked the bottles by hand. The bottling machine was new to Mr. Van Roy, though he had purchased it used from a Burgundy vintner, and he eyed it suspiciously. If a bottle of kriek was not filled entirely, he topped it off from a bottle at hand. "Doing the best that I can, that's what keeps me busy," Mr. Van Roy said.

In Brussels, at least, Jean-Pierre Van Roy is not alone in linking the beer's fate with the city's. "Without gueuze, it's no longer Brussels," said Gustave Abeels, 67, president of Cercle d'histoire et d'archéologie Les Marolles, a local historical society. "Gueuze is the champagne of Belgium."

In a Brussels office not far from several abandoned lambic breweries, Mr. Abeels recalled when les bruxellois commonly drank gueuze in crowded estaminets, small, back alley cafés "with seven tables where you are always uncomfortable."

For his fight against the odds, the Cantillon master brewer deserves praise, said Mr. Abeels. He added with a smile that Jean-Pierre Van Roy "is a crazy fellow. He is an artist, an idealist. But we need crazy people to have our traditions."

Birthplace of a Beer
About an hour's drive from Brussels between Halle and Waterloo leads to Payottenland, which takes in Lembeek, Beersel and its castle; as well as several other Belgian towns considerably less picturesque.

We stop first in Lembeek to visit the Boon (pronounced "bone") brewery, which lies at the end of a narrow lane bordered by a meandering canal thickened with weeds. On a splendid spring morning, the air is fresh, the light soft. Flowering bushes and budding trees sparkle with color and life. Lembeek's jumble of low rooftops form a pleasing background pattern of brick and tile.

Inside we find the fair-haired and rosy-cheeked Frank Boon, who has only a few moments to talk before leaving for an appointment in Antwerp. He asks me the time, but before I can cock a sleeve and consult my wristwatch, Boon peers beyond the darkened entry of his brewery toward the town clock high on a church spire. Like flaming arrows, the gold leaf hands on the church clock shimmer and flash. Bruegel's Flemish peasants, gazing from surrounding wheat fields, may have also told time by the Lembeek clock, and with much the same view to charm them. Even more likely, those long-gone peasants celebrated with pitchers of lambic beer the raucous weddings and feasts that helped break up the drudgery and monotony of their lives.

Frank Boon ranks among the handful of lambic brewers working here in the face of technology and encroachment by lagers and ales. Unlike most, though, he is relatively young. Rare enough, too, Boon's business is apparently thriving, owing perhaps to a baby boomer's penchant for marketing. In summer 1993, Boon began exporting to the US his full line of traditional lambic beers (gueuze, kriek, framboise and faro) under the umbrella of Vanberg & DeWulf, a Cooperstown, New York firm which also markets Duvel, Scaldis (sold in Belgium as "Bush") and other Belgian brewing specialities. Last year, the World Beer Championships named Boon "microbrewery of the year."

The Lambic Question
Not surprisingly, the Lembeek native is especially knowledgeable on the pressing question of whether or not "lambic" beer owes its name to Lembeek. As he wanders down aisles of enormous casks holding lambics in various stages of evolution, Frank Boon recites the case for a Lembeek/lambic connection.

Lembeek is a decidedly quiet town for the late 20th-century, but in the 17th-century, according to Boon, it was home to 40 breweries attracted there by the advantages of its status as a "free town" exempt from royal taxes. "When a French revolutionary government was installed in the 1790s," Boon continues, "the tax-free tradition was maintained in Lembeek despite the monarchical antecedents. In fact, the revolutionaries rescinded all taxes on alcohol, as good an indication as any that their support lay more with beer-drinking sans culottes than refined nobles who owed their wealth to tax levies and in any case, would have preferred burgundy and brandy."

Only when the fair-minded Napoleon came to power -- he put a tax on everyone -- did Lembeek brewers finally have to pay the revenuers. By then, "lambic" beer was as firmly established in local language as "port" wine among the English (similarly, a corruption of "Oporto," the Portugeuse city from where port is shipped around the world).

Far less picturesque--and a much shorter story--is the alternative theory, which Boon dismisses, that "lambic" beer was once brewed in distillery kettles known in French as "alambics."

Like Frank Boon, his visitors prefer to believe the Lembeek-lambic connection because it helps elevate the quiet town out of the ordinary. Without the brewing history, Lembeek has little to recommend it to the modern world. The village square on a weekday stands as empty of life as if it were abandoned. In a darkened café, a visitor stumbles through a short conversation awkwardly mixing French, English and Flemish only to discover that the proprietor of another Lembeek concern, the legendary "Congo" café, has recently passed away. His widow, it is said, still opens the place from time to time but has no regular schedule.

In order to avoid as much as possible such harsh reminders that lambic beer drinking stands in the same relation to the late 20th century as novel reading (a quaint habit enjoyed by the old and the eccentric), any tour through Payotennland is best taken on back roads. Crossing Payotennland, we travel cobblestone stretches of the Brabantsebaan, an ancient Flemish thoroughfare. We pass farmers preparing fields for spring planting.

Bottles Signed By the Artist
In Beersel, we halt for lunch at De Drie Fonteinen, a brew pub serving thirst-quenching gueuze in open-mouthed ceramic pitchers of the kind so obvious in such Bruegel images as The Peasant Dance and The Wedding Feast.

Refreshed by the excellent Belgian country cooking as much as the gueuze, we continue to the other side of town, curling around the imposing Beersel chateau, until reaching the Brouwerij Museum.

An Opel flatbed truck has just left behind a load of empty green 100 cl. bottles. In the driveway, brown flakes lie thick on the ground as if left by a flurry of hops. Inside the dark and dusty brewery, Henri Vandervelden is marking bottles with identifying chalk lines (white for gueuze, pink for kriek). A greying man with a thin mustache and worn old hat covering his head, the brewer has no time for a tour. His chores that afternoon, he explains in heavily accented French, include handwashing the newly arrived bottles (to use a machine, says Vandervelden, risks introducing chemicals harmful to the beer).

Quickly enough, we buy several bottles of beer; a pair of gueuze glasses bearing the brewery's Oud Beersel logo; and some post cards. We spend the equivalent of $12. Vandervelden is clearly too busy to bother with making money. He has a personal crusade to occupy him thoroughly, brewing, bottling washing and all.

"Modernism is imposing itself," this Flemish Don Quixote says with a sigh while his eyes consider the dilapidated brewery. "I can do nothing." It's a surprising admission from someone so determinedly tilting at windmills.

We leave not sure how much longer Vandervelden can maintain the façade. He returns to his bottles and colored chalk. Hunched on a three-legged wooden stool, Vandervelden signs his work individually like an artist with a limited set of prints. In no time at all, we encounter a rush hour traffic jam coming into suburban Waterloo.