ONE FASCINATION in the study of wine is delving into why certain winemakers consistently outperform their adjoining neighbors; why certain wines seem to have an extra measure of interest, depth of flavor and character. The most significant factor in making fine wine may be the weather, but that is synonymous with chance or luck, and therefore beyond human management or control.

Regardless of the expertise of the winemaker or the conservative winemaking techniques employed, great wine cannot be made unless nature provides abundant sunshine, adequate rainfall and a long enough growing season to insure optimum grape maturity.

But the art of fine viticulture also includes factors within the control of the winemaker. And by observing the finest of the profession one can identify clues to their success, which I have distilled as the 14 keys to making great wine:

Soil--The French have always attributed paramount importance to the soil in the production of great wine. Soil does indeed significantly influence the style and quality of wine. Simply taste the wine made from grapes grown in gravely, well-drained soil, versus a wine produced from the same type of grapes grown in heavy clay soil; the differences are immense. The greatest wines come from those soils that are composed of a great deal of gravel and limestone.

Location--The world's finest vineyards are always planted on slopes. There are no great wines made from vineyards that are situated on plateaus or valley floors. The angle of a hillside vineyard influences drainage and available sun. It is not surprising that great vineyards usually have an eastern or southeastern orientation.

Management--No great wines, regardless of the soil or vineyard location, can be made without a human commitment to produce top wine. Effective, firm leadership and management are absolutely essential; I know of no world class-wine that does not possess a good management team.

Pruning--Those vineyards that are aggressively pruned to limit the yield produce the finest wines. While the more rigorous the pruning, the less the production, the wine from a rigorously pruned vineyard is richer and more concentrated. Greedy producers who do not prune and therefore overcrop, produce weak, diluted wines. As the French say, the cardinal rule for making great wine is "faire peu mais faire bon," make little but make good.

Spraying--The best made wines are a result of the use of chemical sprays--despite the expense of new anti-rot sprays--particularly in years when the weather conditions have promoted the development of rot in the vineyards.

Fertilizers--The overuse of chemical fertilizers results in abundant crop yields with the final wine lacking varietal character and intensity. The world's greatest wines are produced from vineyards that permit only the use of organic fertilizer or judiciously limit the use of chemical fertilizer.

The Harvest Dates--Great wine producers are usually the ones who pick as late as possible, thereby obtaining the maximum ripeness necessary to achieve full-bodied, intensely flavored grapes. However, waiting until the last moment to harvest grapes can be very risky, as rains or stormy weather can wash out the hopes of a great vintage. For this reason, the majority of wine producers, not concerned with making great wine, pick much earlier than producers who are attempting to render great wine.

Selection of Harvested Grapes--The best managed estates and wineries make a strict selection of incoming grapes. Conscientious producers will normally separate grapes from old vines and young vines, and vinify them separately. Grapes from old vines always produce the deepest, richest and most interesting wine. Therefore, the top wineries frequently sell off the wine from younger vines under a second label, or sell it in bulk. Producers who seem to be concerned only with the quantity of wine produced, make no selection of the harvested grape.

Vinification--The style of wine desired by the winemaker is dictated by the style of vinification chosen. If big, rich, tannic red wines are preferred, a long, warm vinification is utilized. If a short-lived, fruity, soft red wine is sought, a cool, short vinification is selected. Today's best white wines are fermented at relatively cool temperatures to preserve their inherent freshness and charm. Regardless of the type or style of wine preferred by winemakers, good estates closely monitor vinification and insure that the temperature does not get too high or the fermentation stops altogether. This requires constant monitoring for 24 hours for every day the vinification lasts.

Assemblage--This French word meaning, "to assemble," refers to the process that occurs after the wine has been made and the fermentation is completely over. At this point the wine is transferred to holding tanks. Conscientious wine producers will then make extensive tastings of all the different tanks to determine which lots, or cuvees, are the best. If quality rather than quantity is the winery's guiding philosophy, only the finest tanks of wine will be allowed to be assembled or used for the estate's wine. The other tanks will be sold off under a second label or in bulk. The best wineries today will often discard 20 to 25 percent of their total production in a good year, and 40 to 50 percent of their production in a poor year. It is this selective process which insures that only the best wine gets bottled.

Use of Small Oak Barrels--Many red wines and a few white wines benefit enormously from exposure to new, small oak barrels. Use of these barrels can add a complex, spicy, oaky component to the wine. However, overaging of wine in small oak barrels masks, and sometimes obliterates, the character of the wine, and can frequently be employed by a crafty winemaker to conceal the faults of a poorly made wine. Nevertheless, the controlled use of new oak barrels is usually a sign that a winery is committed to making fine wine.

The Elevage (racking, topping, fining)--The French term "elevage" means to bring up, or raise the wine. It refers to the period of time that the wine spends in the winery prior to bottling. It is at this time that great attention and fastidious detail must be given to the young wine. If the wine is kept in small barrels, it must be racked, or transferred, regularly from the deposit that it throws, or it will become spoiled. Careful attention must also be given to keeping all barrels topped off with fresh wine so that no air space is present in the barrel. Such an air space would promote the formation of dangerous bacteria in the wine, causing it to become vinegary and flawed. Last, the wine must be fined. Fining clarifies the wine so that it is clear and brilliant to the eye. If these steps are not properly and regularly done during the period of the wine's adolescence, the wine will usually possess off-odors, disagreeable flavors and a poor, hazy appearance. The best wines are produced by estates that maintain a large enough staff to insure the proper racking, fining and topping of the wines.

Cleanliness--While many great wineries are old, they can not produce great wine if they are dirty. The finest winemakers I have met have always underscored the importance of cleanliness. Off-odors in bottled wines are the result of dirty conditions in the wineries. The top wineries all share a fanatical desire for clean equipment and wineries.

Filtration--One of the great tragedies of modern winemaking is the increasing number of great wines that are filtered so that the formation of sediment is precluded or, at the minimum, retarded. This process, which serves to strip or eviscerate much of the wine's character, has come about as a result of ignorant buyers, both in the trade and at the consumer level, rejecting bottles of wine that contain a deposit in the bottom of the bottle. There are many winemakers here and abroad who simply refuse to filter their wines, in hopes that the consumer will eventually get smart and realize that unfiltered wine with sediment has a great deal more flavor and interest than filtered wine. If you don't think so, the next time you visit a winery that filters, and is in the process of bottling the wine, taste the wine from the bottle that has been filtered, and then compare it to the wine in the holding tank, which is unfiltered and awaiting bottling. It takes no special wine skills to taste an astonishing difference. The unfiltered wine is always more interesting. Certainly, the greatest wines today remain those which are unfiltered.

There are numerous other factors that impact on the making of great wine; however, these are the fourteen I have found to be consistently shared by the leading vineyards and wineries both here and abroad.