The Oak Knoll District’s ideal soils, seasons, and conditions allows for farming Zinfandel using old world techniques. The first Zinfandel vines in Napa Valley were planted in what is now called the Oak Knoll District, which lies within the much cooler, breezier southern half of Napa Valley – nearby San Pablo Bay (the northern section of San Francisco Bay). The historic head-trained vines that we specialize in, in particular, require intensive vine by vine hand work to ensure a balanced crop, and uniformly ripened bunches. Annual soil amendments with cover crops of beans and grasses, and organic compost are used regularly each growing season to promote vine health and grape skin thickness.
In a valley-wide effort to protect the Napa River ecosystem and its native fish populations, Robert Biale Vineyards employs farming practices that are designed to conserve soil and river water levels, and is in the process of joining other Napa Valley grape-growers and farmers in completing the new Napa Green Certification and Fish Friendly Farming initiative. Water conservation is a keystone element of both initiatives.
A glossary of farming practices and terms that we commonly use at Robert Biale Vineyards:
Dry farmed/non irrigated. Vines thrive on natural rainfall only and roots are challenged to find water. Napa Valley’s average rainfall is around 24”, most of which falls in winter and spring.
Head training. The old vine training system whereby the vine is trained aside a grape stake only then eventually shaped into a goblet that gently shades the fruit and allowing the leaves to capture sunlight.
Soil amendments. Organic material that when spread throughout the vineyard drives nutrients into the soil.
Mowing. Usually the first pass of the season in early spring by tractor that reduces the vegetation that has grown among the vines during the winter months.
Disc-ing. The breaking up of the compacted soil usually done by tractor in late spring that drives the cover crops, oxygen and nutrients into the soil
Hoe plowing, Hand hoeing. Removal of weed growth between the vines that precludes the use of herbicides.
Flowering, Fruit Set. The crucial period in late spring when the grape flowers self-pollinate and form bunches of grapes and determines the new crop.
Shoot-thinning. The vine by vine removal by hand of unwanted new secondary growth that can rob the vine of energy needed to promote the primary growth and ripening ability of the fruit.
Trimming wings. The painstaking removal by snipping with hand shears of secondary grape clusters that form on the sides of primary bunches. The wings can rob the primary fruit of sugar and sometimes lead to mold, mildew, and even rot where the bunches conjoin.
Leafing. The hand removal of excess leaves on the canopy according to the season to allow air-circulation around the forming fruit and balancing the leaves and fruit growth.
Veraison. French for “moment of truth” when the grapes turn from green to blackish purple, usually around late July, early August. This is a crucial period to determine which bunches to remove while leaving those that will be fully ripened.
Green dropping. Near veraison, the removal by hand of lighter-colored bunches of grapes that are lagging behind the primary “blacker” crop.
Hand harvesting. Usually starting in September, fully ripened fruit is picked by hand into boxes that are transferred to half ton bins for delivery to the crusher. Night harvesting during the coolest hours of the morning that reduces the need for refrigeration in the winery.
Bird houses. The strategic placement of specially constructed houses among the vines to provide habitat for owls and bluebirds that are predators for unwanted rodents and insects.