Maybe the trend-setters thought "brie and chablis" had a nicer ring than "brie and burgundy." Or maybe it was the fact that a blotch of pale riesling is more easily removed from a tablecloth than a streak of ruby cabernet.

Whatever, American wine bibbers are sipping a lot more white wine than red these days, a fact that has uncorked a rousing debate among American winemakers and pressed an unusual regulatory problem on the Treasury Department's Bureau of Alcohol, Tobacco and Firearms.

American winemakers, it seems, were caught purple-footed in the late '70s when consumers began to turn away from the red wines that had dominated the market historically.

Faced with a growing demand for white wine -- and, alas, vineyards heavily planted in red and black grapes -- some wineries turned to the government for help. They got it two years ago, when the BATF agreed to permit the use of activated carbon or hydrogen peroxide as "color reduction" agents.

Thus bleached or filtered, the darkest fruit of the vineyard may be turned into the palest white wine. A bottle blonde, as it were.

But the practice has drawn indignant objections from the industry's traditionalists, who tend to see it as oenological blasphemy, and now the BATF is reconsidering its decision.

Spearheading the fight against the peroxide blancs is California's Wine Institute, which represents more than 480 wineries in the nation's biggest wine-producing state.

"We had felt and still do that these materials were not good commercial practice," said Wendell Lee of the institute's legal department.

Because most grapes produce a nearly colorless juice no matter what the color of their skin, Lee noted, it is already possible to produce, say, a white zinfandel, simply by separating the skins from the juice before fermentation.

Whether the peroxide process is easier or cheaper, Lee could not say. "I'm not a technician," he said. "As I understand it, it's a substance that will strip more color than is possible naturally."

The BATF approved the practice at the request of New York winemakers, who were hoping to turn that old standby, the concord grape, into something besides jelly. New York is awash in concords, and it takes five or six years and several thousand dollars an acre to switch to more marketable grape varieties.

But James Trezise, head of the New York State Wine Grape Growers Inc., said the question "is actually pretty much moot now."

"What's happened is that concords are not being bought for wine anymore," he said. "We can't even get rid of the rieslings. There's a wine glut. We have too many grapes, period."