If it’s December, it’s time for a flute of sparkling wine, in particular “le champagne.”

That’s just one thing I learned at a recent champagne seminar in San Francisco: The proper term for the world’s most celebrated sparkling wine is “le champagne.”

Another: That it comes only from “La Champagne,” the French wine region 90 miles northeast of Paris.

I’d long thought that “Champagne” stood for both.

The clarification was the first of several lessons that two members of the North American chapter of the Institute of Masters of Wine – Charles Curtis and Joel Butler – presented at North Beach’s fittingly chosen Bubble Lounge. (Butler, of Seattle, is a wine educator and the author of the book “Divine Vintage: Following the Wine Trail From Genesis to the Modern Age,” while Charles is a New York-based wine writer and consultant.)

The upshot was that for all the romance, magic and joy that “le champagne” generates, it originates in a remarkably rigid culture. Just about everything involved in making champagne is sternly regulated – the type of grapes that can be grown in the region, the spacing of rows in vineyards, the kinds of trellis systems, how much juice can be squeezed from a load of grapes, and so forth.

Maybe that’s what it takes to produce the world’s most exhilarating drink.

The champenoise hope to renew interest in champagne in the United States, where annual shipments slipped to 17.7 million bottles last year from a pre-recession high of 23.1 million in 2006. More growers are hanging on to their grapes and making champagne under their own brands rather than selling all the fruit to negociants and cooperatives, their traditional outlets.

The large champagne houses, called “grande marques,” still dominate the trade, accounting for 88 percent of shipments to the United States last year, but that proportion has fallen from 94 percent a decade ago.

These houses include such long-established, high-profile brands as Moet & Chandon, Veuve Clicquot, Dom Perignon, Bollinger, Pol Roger and Krug.

In the meantime, the proportion of grower-made champagne shipped to the United States has been inching up, from just 2 percent of shipments a decade ago to 4.2 percent last year.

“There’s no need for antipathy between the two,” cautioned Charles Curtis at the outset of the seminar. Growers share with the grande marques an appreciation of Champagne’s regulations, but when those standards permit some flexibility, the growers are likely to take advantage of it. Several growers, for example, have returned to the early Champagne practice of fermenting juice in barrels, whereas larger producers rely on more-efficient stainless-steel tanks.

For the most part, the grande marques have developed standing with styles of champagne that are relatively steady. For them, consistency trumps variability, with the winemaker’s skill at blending taking precedence. Their champagnes not only are likely to represent a blend of the three principal grape varieties in Champagne but a blend of vintages to compensate for wild fluctuations in the availability and quality of grapes from year to year, due in large part to the region’s extreme weather.

Some producers, however, are “throwing consistency out the window,” says Butler. And those producers are apt to be growers going their own way.

Growers also are at the forefront of a movement within Champagne to lower the “dosage liqueur” – a mixture of wine and sugar added to champagne near the end of its processing – for a better-balanced and less-sweet champagne.

Aside from that, what are the stylistic differences between grande-marques champagnes and grower champagnes, if any?

For Charles Curtis, who says he drinks three or four bottles of champagne a week, grower champagnes have more “vitality, energy and zip.”

For my part, based on a tasting of nine champagnes during the seminar, followed by a second champagne tasting later that day at the Ferry Building, where 90 examples were poured, I found the grower champagnes leaner, drier and racier than the grande marques.

Broadly speaking, grower champagnes had more vigorous beads of bubbles, more mineral tones and snappier finishes. By and large, they were champagnes that would stand out more at home during an intimate dinner party than during the tasting at the Ferry Building.

The grande marques, in contrast, were larger wines, with more-forward fruit, more-languid bubbles and more overall richness. They showed a comfortable authority and could be relied upon to deliver the weighty nobility that over the centuries champagne has come to represent.

For sure, exceptions could be found in both camps, with some grower champagnes husky and complicated, some grande marques taut and direct.

While grower champagnes constitute an exciting movement in Champagne, they aren’t yet especially easy to find in the United States. Of the nearly 18 million bottles of champagne shipped to the United States last year, only about 750,000 were by growers. But take heart, that figure represents a jump of nearly 100,000 bottles over the previous year.

If you are tempted to explore grower champagnes this holiday season, keep an eye out for the Gaston Chiquet Tradition Brut ($50), whose fine beads of bubbles belie the concentrated flavor it delivers; the solidly structured, mouth-filling and earthy Pierre Paillard 2002 Grand Cru Brut ($60); the citric, stony and wonderfully aromatic Pascal Doquet Grand Cru Le Mesnil sur Oger Blanc de Blancs ($50/$55); the fine-boned, strawberry-scented and downright gripping Henri Billiot Brut Rose ($50/$60); and the hefty yet sharp-edged Pierre Gimonnet & Fils 2005 Special Club Millesime Brut Cuvee ($70/$90), a veritable cross section of all that champagne can be, revealing apples and lemon rind, mushrooms and tea, brioche and nuts, and on top of all that the tallest, densest mousse of the day.

Of champagnes from larger producers, my favorites were the nutty and persistent Piper-Heidsieck 2002 Rare Brut ($150); the full-bodied, apple-scented Bollinger Special Cuvee Brut ($55); and the concentrated and soulful Charles Heidsieck Brut ($55).

The French, incidentally, have a shorthand on their labels to alert shoppers to whether a bottle is made by a large producer or a grower. “NM,” for “negociant manipulant,” designates a traditional champagne house that has purchased its grapes, while “RM,” for “recoltant manipulant,” and “RC,” for “recoltant cooperateur,” signifies that the bubbly has been made directly by a grower or by a cooperative under his direction.

Now it’s time for that flute of sparkling wine, by whatever name or code.