When you taste the red wines of Santa Ynez," Andre Tchelistcheff warned, "clear your mind. Don't seek comparisons. They're completely different."

Tchelistcheff is the great winemaker who produced Beaulieu Vineyards' standard-setting cabernet sauvignons from the late 1930s through 1972. Now he is a consultant to more than a dozen wineries in California as well as one in Oregon and Chateau Ste. Michelle in Washington state. These wines and the vines they come from are Tchelistcheff's grandchildren. They will be his legacy - an invaluable one - to the wine industry that he, more than any other individual, awakened to its potential for quality.

They also serve to underline one of Tchelistcheff's strongest arguments: that soil, as well as climate and grape selection, is a vital factor in winemaking. He has conducted along campaign for recognition of the regional characteristics of California wines.

As the wineries he advises come of age - from Firestone in the Santa Ynez Valley near Santa Barbara, to Simi and Jordan in the northern part of Sonoma County - evidence is accumulating in bottle after bottle.

Just as it is nonsense to declare, as simple-minded propagandists still do, that "every year is a great wine year in California," it is equally apparent that the wine areas of this state should be personalized as are Burgundy, Bordeaux and other regions of France.

"Napa Valley" still is the symbol for California wine to many Americans. But nearby Sonoma County now boasts 65 winteries. There is dramatic growth and great promise in the coastal range area between San Francisco and Santa Barbara. In the often maligned San Joaquin Valley, with its desert climate, the banal Thompson seedless has given way in many vineyards to grapes such as chenin blanc and ruby cabernet.

A chardonnay wine from the Alexander Valley may possess quite different characteristics than one from Napa. Botrytis-infected rieslings picked in Sonoma have made some spectacualr dessert wines, while botrytized grapes in the central valley often contain harmful bacteria as well. The central Napa Valley, Tchelistcheff has long argued, is not suitable for growing pinot noir. He is encouraged, however, by pinot noirs made from grapes grown in the Carneros Creek area, at Firestone and at the Hoffman Mountain Ranch near Paso Robles.

Regional distinctions are complicated by several factors, however. Several varieties of grapes grow in each region, and indeed in almost every vineyard. Also, grapes may be shipped to a winery from several miles away or from another area altogether.

The ranks of well-financed wineries with high artistic ambitions have been swelling. A number of them plan to use only grapes from their own vineyards. To stay solvent while the vines mature (it takes about seven years, with no usable grapes at all for the first four), wines are made from purchased grapes. In time, these European-style production centers should set the standards for regional identification.

Some high-minded wine lovers have been pressing the government to insist on clearer definitions and stricter regulation of growing areas. Without such action, the potential for consumer deception - inferior wines in misleadingly labeled bottles - clearly exists. On the other hand, a tour of wineries and vineyards in several different regions proves that an impressive amount of genuine research and experimentation is being conducted.

Wineries try aging cabernet and chardonnay in American, French or Yugoslavian oak. At Sonoma Vineyards, Rod Strong laughed as he explained how "a guy with a $2 pitchfork" is used "to put the stems back in the pinot noir that our $30,000 crusher removes so efficiently." There's a movement back to traditional methods of fermenting wine from this grape. Frank Woods of Clos du Bois talked about how much was learned from the drought year of 1976 and as a result how differently his grapes fared during 1977, also a drought year.

"How good are our wines?" said Brooks Firestone. "We really don't know yet. I don't think we can make any claims until we've been through at least five harvests and have some age on our reds."

"How long will our reds last? I don't know," said John Parducci several hundred miles to the north in Mendocino County. "There's no track record. Our 1969 pinot noir is just becoming drinkable. We have new appellations, new vineyards, new ways to do things. The challenges keep you going!"

It seems far too early to draw the lines and limit the grape varieties. Winemakers should be given time to impart a discernible style to the range of wines coming out under the banner of a single winery, and to develop a shared philosophy of what each area does best and how to achieve its potential.

In the meantime, cheaters may thrive. But the criteria of excellence in wine are so subjective and competition is so keen that a strong argument can be made for a laissez faire policy by government. (This is not to say the push for tighter and unambiguous label regulations should stop. Allowing the winemaker freedom to experiment doesn't negate the consumer's right to know what is in the bottle.)

Amid all the theorizing and experimentation, there appears to be a steadily increasing realization - perhaps underlined by the two years of drought and this year's rich harvest - that great wine comes from great grapes.

"This year we made some long-term contracts to ensure a supply of the best grapes," said Tom Farrell, the senior winemaker at Inglenook. "We take the credit (for a superb wine), but often the vineyard has done the work for us. We only need to babysit with it. Some of the greatest winemakers we have are the guys who turn out decent, drinkable jug wines vintage after vintage."

"I can't imagine myself standing at the door of the winery waiting for the grapes to come in," said Rod Strong, who supervises Sonoma Vineyard's 1,600 acres as well as making the wines. "I don't know any magical tricks I can do in the winery with mediocre grapes."

Most wineries have to buy grapes, which may lead to a conflict with the grower. The quality-conscious winemaker wants to limit production by severe pruning, by denying the vine water and other methods. The natural instinct of the grower, who usually is paid by the ton, is to maximize yield.

Gallo long ago established a grower relations department to set standards and disseminate technical information. Contract vineyards are inspected by Julio Gallo personally. The winery monitors grape health and quality at the harvest site and again before crushing. Chateau St. Jean in Sonoma has been an innovator in writing contracts that not only pay higher rates for reduced production, but contain restrictions and incentives intended to produce thoroughbred grapes with specific personality traits winemaker Richard Arrowood desires.

The rub comes when a winery gives credit to the grower on the label, building his reputation, then sees the grower go into production for himself. For this reason, some wineries are leery of designating the vineyards that produced their grapes.

Another problem has arisen due to the rapid increase in wineries (there are now nearly 400 bonded wineries in the state, almost double the number in 1961.) Competition for the best grapes is fierce. "Some newcomers," said Francis Mahoney of Caneros Creek, "will pay any price for grapes to get going - to make a wine that will establish their reputation."

Mahoney contracts before the season for a fixed price per ton. He paid $750 a ton this year across the board for several varieties of grapes. "It provides insurance for the grower," he said, "and makes life easier for me because I can lay out a cash protection for the cost of grapes."

If buying wine and judging quality is hard for the consumer, creating it is even more difficult. "We learned everything by touching," said Andre Tchelistcheff as he talked of his struggle to rebuild the industry wiht a quality image after Prohibition. That was 40 years ago and while the infant has grown impressively, it is still only a child.