Mr. Cakebread looks after the flavor of his wine in part with the help of a neutron probe, a hand-size device with a built-in radioactive source that measures soil moisture during the growing season. If a lot of water' is percolating through the soil, neutrons will be slowed by collisions with the hydrogen atoms in the water. The device measures the number of slowed neutrons, a reliable indication of moisture.
     Of course, not every winemaker has a laptop in the tasting room. At Ridge Vineyards in the Santa Cruz Mountains above Cupertino, Calif., for instance, no computer is permitted to monitor the temperature of the winery's complex, highly regarded reds as they ferment in their stainless-steel tanks. "We measure the temperature by hand," said Paul Draper, who has been the winemaker at Ridge for 29 years.
     Indeed, Mr. Draper, who laughs at the thought of entrusting the temperature of his wines to sensors immersed in the liquid, oversees the making of wines so natural that no yeast is added to speed fermentation. "We allow the natural yeast on the grapes to carry out the fermentation," he said. "And no probes, of course. We prefer to smell the fermentation and determine how it's going--to be in direct human contact with each tank."
     But at wineries like the Robert Mondavi Winery in Oakville, Calif., highly sophisticated technology is used to check beneath the vines to improve the taste of ripening grapes as well as to check the vines from above, using fly overs with digital sensors and cameras.
     Since 1993, Mondavi has collaborated with the
National Aeronautics and  Space Administration on two projects designed to adapt NASA's remote-sensing technology to the wine-grape industry.       
     Although the French, after centuries of grape growing, may know every inch of their vineyards, Daniel Bosch, the technical manager of the vineyard at Mondavi, said: 

"Technology can help us play catch-up. Aerial images give us the data to see the differences that Europeans have learned by taste over hundreds of years.
     "The images are taken by aircraft flying 13,000 to 15,000 feet above the vineyards. The planes are equipped with special digital sensors that collect multispectral images-images taken not only in the visible but also in the near-infrared parts of the spectrum.
      The images yield a sensitive measure of the chlorophyll content of the vines,   which says a lot about the taste of the fruit.
     "The images were sensitive enough to show us that some of the grapes were high-vigor, others medium-vigor, others low-vigor," Mr. Bosch said. "Each level of vigor is unique in its taste."
     Using multispectral images of a special demonstration vineyard, Mondavi could identify reserve or high-quality grapes. "The block had never before yielded re-serve-quality grapes," Mr. Bosch said. "We could locate them because of the differences in their images."
     Lee F. Johnson, a scientist at the NASA Ames Research Center in Mountain View, Calif., was responsible for the pilot projects at Mondavi. "The French have had many years to adapt their management practices perfectly to the countryside," he said. "They don't need us as much as Napa does."
     Mr. Johnson became interested in wine grapes in the early 90's, when vineyards, particularly those in the Napa Valley and to the west, in Sonoma County,   were severely afflicted by phylloxera, or root lice, and forced to replant up to 80 percent of their vines.
    "At first we collaborated to transfer our technology
to help detect phylloxera and improve vineyard management in the face of it," he said. "It turned out, that the aerial images were one way to customize and get the best grapes possible out of the system."
     Mr. Johnson expects that

satellites will start carrying this kind of digital sensing equipment next year. "At present, no satellite systems can give the spatial resolution you can get from aircraft," he said. "But several companies will be launching systems that will work for precision farming so that vineyards can do vegetation analysis from multispectral data."
     Paul Skinner, the president of Terra Spase in Napa, Calif., a technological consulting group that specializes in the wine industry, agrees."Planes get buffeted and tilted," he said. "lt's going to be a lot easier to get precision images once satellites are up that can use the resolution now available on airplanes."
    Dr. Skinner coordinates the collection and analysis of multispectral data taken from airplanes for about 30 California vineyards. He combines the data with the information gathered by his soil and moisture programs to create profiles of the vineyards.
     "People can't just walk out and see what's ripe with a 40-acre vineyard," he explained. "Even if they pick clusters off at random to decide, they may miss very significant areas within the vineyard. Now we have the data from above and can put it together with the data on the ground and below to make a powerful connection between the grapes and their vigor or strength."
     What will this mean to anyone who is toasting the New Year? Will all this specialized information produce a tastier wine? Mr. Bosch, of Mondavi, said that even tile French thought so: "When I was speaking in Burgundy this summer to wine growers about our project, they said the new technology had brought the United States forward 1,000 years. From the French, that's a compliment it means we have only about 500 years to go."