The controller on each new tank is the TankNet system (Acrolon Technologies, Sonoma CA).

The winemakers are very pleased to have automated control of heating/cooling and pump-overs. The system can be set for all-heat, all-cool, or automated rotation of temperatures.

In 2007, the tanks were filled only once as the winery is testing the design and functionality of the new tanks. In 2008, they hope to complete two fermentations per tank.

Cabernet Sauvignon grapes were sourced from three estate vineyards in Yountville, Rutherford, and west of Soscol Avenue (north of Napa). Grapes from each property were divided into straight tanks (for control), truncated tanks, and older conventional fermentors. The first harvest to go into the new fermentors came from the Yountville Vineyard at approximately 25° Brix.

Grapes were sorted and went through a Delta-E2 destemmer (18mm hole diameter cage) with an electronic variable speed control. About three tons per hour of grapes were handled very slowly. "The rollers on the destemmer were set as wide as possible to pop berries, but not smash them," reports Damian Parker, vice president of production. A Waukesha- 220, 4-inch positive displacement pump transferred the must to the fermentor.

At Joseph Phelps, the juice is left on the skins for about 20 to 30 days total skin contact. Winemakers typically do a four-day cold soak, then inoculate. Pump-overs are one to four times per day depending on the stage of fermentation.

Between 18° and 12° Brix, one complete delestage is done.

Joseph Phelps Vineyards usually macerates to or past dryness, though Hepworth says, "The decision on when to press off the skins is made by taste. In Bordeaux, my observation was that enologists perform more extended maceration than California winemakers tend to do."

The winemakers at Joseph Phelps eagerly await the results of their new fermentation system. Gentle handling and delestage should ensure a highquality wine with enhanced color and soft tannins.