Any day now, this year's beaujolais nouveau will arrive in Paris and be pronounced (probably) good or great. Vintage 1979 wine will be a reality.

Through the coming winter and spring similar judgments will be made in wineries around the world. Prices will be set and over the next few years the public will be introduced to the wines that nature and man have fashioned over the past seven months. Cards -- vintage charts -- will be printed listing wine regions and a sequence of years ending with 1979. Beside or beneath each you will find a number or symbol, a rating of the vintage.

Knowledgeable merchants and sophisticated consumers deplore these vintage charts. How, after all, can you pour the wines of an entire region into a single number, especially when there is such a rush to judgment? The ratings are released before the wines are. Consumers and the retail trade don't have time to make up their own minds. Show them a low number, 6 or even 7 on a 10-point scale, and sales of that year's wine will be seriously slowed.

Vintage ratings, as they are used topday, are a rather recent phenomenon. There is no official body that makes these ratings. Most come from wine companies, wine appreciation societies and writers. They gained popularity in England and the United States, two statistically minded countries where wine consumption has been a hobby rather than a way of life. In much of the rest of the world, with as much as 90 percent of the wine that is produced, vintage is almost meaningless. Wine is drunk within a year -- perhaps two -- of its manufacture.

Think of the lower-priced jug wines on sale here. There is no indication of the year in which they were made. Chances are, from mid-winter on, it is from the most recent vintage, or it may be a blend of more than one year's wine. This allows the winemaker to balance out abundant and scant production, acids, sugars and flavor to deliver a consistent product.

Vintage wines are not consistent. That's what causes all the interest. Vineyards people like to fuss about most -- in Burgundy, Bordeaux and along the Rhine and Mosel rivers in Germany -- are located on the fringe of climate zones that provide enough warm sunlight to charm grapes into becoming rich enough in sugar to ferment successfully into wine. To make a dangerous oversimplification, the number on your vintage chart is -- in essence -- a weather report. A cold spring, untimely hail or rain, too little sun in late summer -- any of these can affect the quality of the wine and lower the vintage rating.

What, then, should the rating mean to you? By itself, nothing. Too many overeager consumers have bought wine from "great" vintages only to be bitterly disappointed. It may take such wines 10 or 15 years to mature. Few consumers want to wait so long. Bordeaux red wines of the 1962 and 1967 vintages were judged well below 1961 and 1966, yet they matured relatively fast, generally outperformed their medicore ratings and provided considerable pleasure while their illustrious predecessors were inching toward drinkability. Consider your own needs and tastes before demanding the "best" year.

At the other extreme, drinkers have found joy and great bargains in bottles from vintages the overeducated have shunned. Not every wine is successful in a "good" year, nor is every wine a failure in "off" years. But those who have been buying 1972 wines such as Mouton and Lafite at what appear to be bargain prices are receiving little more than a label to save. These wines are pale shadows of what the chateaux can produce when conditions are more favorable.

Knowing the vintage of a wine can help, just as it helps to know your shoe size. But with wine, as with shoes, you still must consider style, comfort and durability.