The Science of WinemakingBy Carol Fowler
The gray overcast summer sky doesn't bother Andrea "Buck" Bartolucci, president and winemaker of Mont St. John Cellars in the Napa Valley. The Carneros district's unique climate is particularly suitable for pinot noir and chardonnay grapes.
Bartolucci has mastered the intricacies of raising and making wine from the pinot noir grape. "Pinot noir is so delicate that you have to do special things each step along the way to preserve its flavor and character," he said.
Science of making wine
According to the third-generation Napa winemaker, the science of raising the pinot noir grape starts with St. George rootstock, the strain he chose when he planted the bare 160-acres in 1970. The hearty, low bearing stock thrives in the district's shallow soil.
When he chose the clonal stock, or mother plant, to be grafted to the roots, he chose a pinot noir with heavy character, which produces a rich Burgundy-style wine. He also dry farms instead of irrigating.
"You don't get as much tonnage per acre with these varieties and with getting all your moisture from mother nature, but you get more intense flavor and complexity in the wine," he said.
By early September, his pinot noir grapes had reached 22-½ percent sugar, when he decided to harvest. Bartolucci also considers the acid and pH level or acidity strength. "As the sugar goes up, the acid comes down but the pH level goes up. You need a pH about 3.3 (out of 7) for a biologically sound wine," he said. The pH level of acidity controls unwanted bacteria.
The hand-harvested pinot noir grapes go through a crusher and stemmer. Red wine grapes are fermented with the skins on, which gives the wine its color. Before putting the crushed grapes into the stainless steel fermenting tanks, he adds 20 percent whole grape clusters to the bottom of the tank. Then he adds the crushed grapes and a dose of yeast.
"When the uncrushed berries ferment in the skin, you get more fruity character. You also get flavor complexity from the stems," he said.
While the must ferments, a thick layer of skins and stems, called a cap, forms at the top. Usually the fermenting red wine must is pumped into a hose at the bottom of the rank and sprayed over the cap to mix the skins with the juice twice a day. Mixing increases color.
"Pumping gave bitterness to the pinot noir, so we use a special plunger to mix the skins with the must," he said.
Aged in oak
Fully fermented pinot noir also stays on the skin and stems several days after fermenting, another exception. "Pinot noir tends to race through fermentation in about three days," he said. "The temperature should be 80 to 85 degrees. At that temperature, the yeast has used all the sugar in a short time. When fermentation is through, we seal the tanks. We let it sit for another 10 or 15 days."
The additional time increases the tannins, which increase the complexity of red wine.
The wine from the top of the tank is drawn off; the remainder pressed. The wine is aged in oak barrels for a year. At least once during that year, the wine is drawn off the sediments that settled out at the bottom.
After bottling, the wine is stored for one year and then released. It's ready to drink then, though it will improve with time.