Perched high atop Pritchard Hill,Ovid Napa Valley’s vineyard boasts a majestic view of Northern California’s wine country. From the front of the property, you can see all the way to the Mayacamas Mountains that divide Napa and Sonoma counties.
This breathtaking tableau is lost for the moment on Thibaut Scholasch, who’s crouched in the vineyard, gently parting clusters of blueberry-sized cabernet sauvignon grapes. “This is a pipe,” he says, holding a vine between his thumb and forefinger. “Water flows right underneath the surface.”We all learned in grade school how a plant conveys water and nutrients to its extremities. But Scholasch, who holds a PhD in grape growing, understands this distribution process far more intimately. With this particular vine he knows precisely how much water is flowing in the pipe at any given moment. That’s because he can see inside.
Scholasch tugs on a section of Velcro and peels back a layer of insulation, revealing a sap-flow sensor. About 3 inches long, it’s a simple device consisting of a heating element, two thermometers, and a transmitter. “There are two wires that measure the temperature, one before the heat is applied and one after,” he says. The difference between the readings indicates the amount of water present. The system, while simple, is powerful enough to unravel thousands of years of farming practices.