Leave it to the French to market a new brand of wine, as if 430 registered vintages and hundreds of other table wines aren't a sufficiently diverse selection.

The Touraine Primeur, a light refreshing red wine, was christened here with all the effusive fanfare due the newest infant in a long, noble tradition.

It's "very agreeable," "goes down easy," "supple, don't you think?" said one wine aficionado to another, as if proud parents would say anything unkind at a baptism.

The wine growers, sellers, testers and promoters of the Loire Valley pushed and shoved to empty the 700 bottles ordered for the occasion in the classical garden reception hall of the Renaissance chateau, which was silhouetted by moonlight in the distance.

Endlessly replenished trays of caviar canapes, garlicy escargots, cream pastries and brandied pate spreads moved up and down the crowd as someone delivered a six-page testimonial to the new addition and of course, nobody listened.

This modest reception inaugurating the wine was nothing compared to the promotion for the Touraine Primeur planned for Paris. Even a necatar so naturally seductive as a freshly bottled wine depends on good PR for success.

That is particularly true here in the Touraine, a northern and relatively small region whose smokey red wines are not highly praised outside a long-cultivated clientele and whose whites, such as Vouvray, are slightly sweet for the preferences of the average consumer in today's dry wine market.

A "primeur" is an extremely young wine, produced in an accelerated six-week process, while most reds don't go into the bottle for a year. The French government has allowed it to be sold since Nov. 15. The agency which regulates the quality of the better wines in France, the Institut National des Appellations d'Origine (INAO), permits only four red primeurs, and two of them -- the Touraine and the Galillac -- were just approved this past fall.

Yet the development of a primeur wine -- which has clearly not reached its potential fullness -- is a curious phenomenon in a country that has boasted of the benefits of aging and maturing its most notable product. Promoters of the Touraine Primeur say, however, that the latest vogue among consumers -- particularly the younger, less wine-savvy sipper -- is an uncomplicated wine, lower in alcohol and in price.

Its main drawback is its life span. A primeur fades dramatically after three months.

"The mode is a light simple wine which goes down easily. We call that quality gouleyant after an old French, slightly coarse word, used by Rabelais," said Bernard Thevenet, director of the Comite Interprofessionel des Vins de Touraine.

"Part of this is the cuisine of today and the style of living. Many people don't have time for long elaborate meals. Some of it is ecological -- consumers want something a little closer to nature, more natural, if you will."

In Tours, the main city of the Touraine, the manager of a moderately priced hotel and restaurant said that Burgundy wines are too expensive and too heavy for his customers. He sells the Touraine red primeur made from the Gamay grape at $6 a bottle, two or three times cheaper than a bottle of Burgundy.

"And the primeur goes very well with all dishes from start to finish of a meal without being shocking," added Henri Malliet. "It's as good at the bar as at the table."

The Touraine wine patrons knew a market for a primeur wine existed because the most popular variety, the Beaujolais Primeur, was introduced with such hoopla on Nov. 15 that hardly a bar or restaurant is without a colorful Beaujolais promotional sign. The Touraine Primeur at $1.75 to $2.50 a bottle in the grocery undercuts the Beaujolais, priced from $2.50 to $3.50.

Now that a simple but decent lunch or dinner out (appetizer, main dish, vegetable and dessert) costs at least $8 in the neighborhood bistro, the practice of changing wines for each course is hardly affordable to moderate spenders.

A primeur or the later nouveau wines (marketed after Dec. 15 but still immature) have certain guarantees on grape varieties and soils attached to them, lifting them a few steps higher than ordinary table wines.

For years, the Touraine wine growers, who typically farm only about four acres each, have produced small quantities of the primeur for themselves and their friends. Its freshness from the newness, above all, is captivating.

Then in 1975 the local wine association petitioned the INAO to approve the production of the new red primeur from the Gamay grape. With permission finally granted in November, 1979, the producers bottled about 400,000 bottles from the latest crop. That is less than 5 percent of the region's red wine harvest this year, but in five years they hope to triple the quantity. One-fourth of the Beaujolais annual crop is bottled as a primeur.

Unfortunately, the Touraine Primeur won't be shipped to the United States this year, and possibly never, even though its zesty flavor would probably appeal to the bar and brunch set. The Touraine growers ship little of their crop to the U.S. "What would 3,000 bottles of the primeur mean to that immense U.S. market?" said Thevenet, shrugging his shoulders.

Undaunted, one Touraine connoisseur, mustering his chauvinism, offered an alternative. "Americans ought to charter planes to get it. They do that for our vegetables and bread, don't they?"