Winemakers must be eternal optimists to survive in their chaotic profession. The job is not easy and there are always risks. The grapes can mature soundly and perfectly over an uneventful summer only to be bloated from torrential late-summer rains or damaged in a freak hailstorm in September.

In France, the grape harvests in all regions are well under way and the fact that the weather is crucial to whether the vintage is fair, good or outstanding now occupies the mind of virtually every grower and producer.

France must have a good 1985 vintage for wine prices to remain relatively stable. The dollar has declined by 20 percent since January and world-wide demand for France's glamor wines has pushed prices for prestigious bordeaux and red and white burgundies to absurd levels. The 1984 vintage was generally below average to mediocre in quality and back-to-back poor vintages would cause a further escalation of overheated wine prices for previous vintages.

However, France should have a very good, potentially excellent, crop if the weather continues sunny and dry for the next two weeks.

For Beaujolais and the Rho ne, the vintage already seems to have excellent potential, as much of the crop has already been harvested. Georges Duboeuf, known the world over as "Mr. Beaujolais," said, "It is the vintage of the sun," and feels that it will be an excellent year for the nouveaux (due to arrive on Nov. 21) as well as the more serious village and cru wines.

The harvest occurred on dry, sunny, hot days and Duboeuf thinks the wine will have the "richness and body of the 1983, but with less tannin and more harmony." Duboeuf is absolutely ecstatic over the quality of nouveau for 1985.

In the Rho ne Valley, the grapes were jet black in color and fully mature when the harvest started on Sept. 20. The only problem is technical, that of controlling the vinification temperature in the high heat; this is the third harvest of the last four to occur in torrid temperatures.

In Burgundy, most growers began to harvest on Sept. 30 for the white wines and last Friday for the red wines. Unlike 1984, there has been no devastating hail, and unlike 1983, there has not been one problem with rampant rot in the vineyards.

Francois Faiveley, the head of one of Burgundy's most prestigious and best firms, said there had been no rain for five weeks when the harvest was scheduled to start on Sept. 30. Additionally, he said that the "drought had caused the pinot noir grapes to attain a very dark color and that the health of the grapes was exceptionally good."

The quantity is expected to be average to slightly below average except in Chablis. There, though the quality is expected to be excellent, the quantity may be 60-75 percent below normal because of last winter's killing freeze.

In Champagne, the harvest was not expected to begin until yesterday, and while the quality looks good, the quantity is expected to be only 60 percent of a normal year.

In the Loire Valley, where the harvest started Sept. 20 in Muscadet and Vouvray, the quantity is normal and the quality is expected to be similar to the very good 1983s. They are expected to be flavorful, yet somewhat atypically soft and fruity. Both Sancerre and Pouilly Fume'' were devastated by last winter's freeze and the crop is one-third normal size. However, the quality is said to be exceptional.

In Bordeaux, the harvest started -- on Sept. 23 for the white wines and Sept. 30 for most reds -- with tremendous enthusiasm and high hopes. The weather had been hot, sunny and extremely dry with drought-like conditions for the last eight weeks.

Jean Michel Cazes of the famous Cha teau Lynch Bages, where the harvest started on Sept. 30, said that if the weather continued for another two weeks, the vintage would produce wines "reminiscent of 1949" and "better than either 1983 or 1981," all very fine vintages for Bordeaux red wines. Elsewhere in Bordeaux, consistent reports indicate that the grapes are deeply colored, fully mature, ripe, have average acidity levels and good to very good sugar readings. In Pomerol and St. Emilion, the cabernet sauvignon and merlot are said to be in excellent condition.

The tiny vineyard of Pe'trus, now Bordeaux's most expensive red wine, was harvested entirely on Sept. 30 and Oct. 1. Other estates in St. Emilion and Pomerol stated that their harvests would be completed this past Monday.

On the negative side, several vineyards planted on sandy soils, or with a high percentage of young vines, have reportedly suffered from the drought of the last two months. These grapes have not achieved the regular and complete ripeness attained by grapes from older vines or vines growing in clay or gravelly soil. The size of the Bordeaux crop is said to be average to above average.

Overall, 1985 seems to be shaping up as a banner year for France's viticultural regions. For the wine consumer, now faced with higher and higher French wine prices, such news can only be "merveilleuses."