Chauncy, the gardenspun philosopher of "Being There," knew that a well-tended plant will bear good fruit, whether it be a metaphorical national economy or a real vine. For some time the emphasis in viticultural research at the University of California at Davis, and in practical application by California wineries, has been on the climate and the vine. One other elementary, and equally important, factor has tended to be overlooked: the soil. William Hill, a Napa grower and winemaker, says, "Soil factors have not been understood and appreciated until very recently. Now, Davis is coming round."

Without a balance of soil and climate, all the wizardry of the winemaker will not produce a fine wine. A vine needs porous, even poor, surface soils and well-drained subsoils, to encourage the roots to dig deep for moisture. This ensures that the vine absorbs minerals and other nutrients found in the subsoils. The more a vine struggles, so the maxim goes, the better the quality of the wine.

Hill is a proponent of mountain vineyards. He favors the mountains over the valleys because the steeper slopes give him the drainage he wants for his style of wine. They're called mountain vineyards, although the slopes of Napa are rarely as precipitous as those of the Rheingau, for instance. They're hillsides, but the distinction between these vineyards and the gentler inclines in the valley is a clear one.

Hill and others believe that a mountain vine will produce different and more complex characteristics. The vine's fight to survive on a steep slope, to dig deeper for water, gives the grapes an intensity of flavor. As the vine is "stressed" by its limited water supply, intentionally so in the last few weeks before picking, the sugars, acids and flavor components become concentrated and the water content is reduced. Hill cites Burgess, Mayacamas, Ridge and Phelps as examples of wineries that have produced intense wines from mountain vines.

Since the '78 vintage, Hill has been producing under his own label.He's planting his chardonnay and cabernet sauvignon on Mounta Veeder and the Atlas Peak areas, in southwest and southeast Napa respectively. He preferred the cooler climate of the Carneros area, to the south of Mount Veeder, but chose the hillsides because of their more suitable soils.

He sold Diamond Mountain Ranch to Sterling in 1977. It's west of Calistoga, in the north of the Napa Valley and high enough that one can stand among the vines and watch the glinders from the Calistoga airfield circle below. Sterling, equally conscious of the importance of soil, has entered wholeheartedly into the mountain soil philosphy. With detailed records, and patience, the firm is monitoring the development of the vines.

sterling doesn't bottle individual vineyards under separate labels. Rather, its mountain wines are blended, after fermentation, with those of their other vineyards, to produce the style the firm wants. It may not be William Hill's style, just as many other Napa vintners prefer to grow in the valley soils. However, Sterling, like Hill, believes that the high coasts, lower yields and inconveniences of maintenance and harvesting of mountain vineyards will be worthwhile.