Cabernet Sauvignon vineyard looking north
Vineyard History
From 1928 to 1978, the Costello family ran a plum orchard on the 40 acres of land we now know as O’Brien Estate. After word had reached Napa Valley of the stunning decision by French wine judges that the Napa Valley wines were superior to those of the highest ranked French wines in the Judgement of Paris in 1976, the Costello’s planted their land in 1978 to 33 acres of Chardonnay.
In 1994 the vineyards were attacked by the Phyloxera louse (which wiped all the French vineyards in late 1800s and much of Napa Valley in the mid-1990s) and re-planted in 1995 to 22 acres of Chardonnay & 11 acres of Merlot. As a bit of a historical note, the only rootstock found to be resistant to Phyloxera is American rootstock from Denison, Texas. Most, if not all, French vineyards are planted with American rootstock to which clones of the fruiting stock are grafted.
We have since re-grafted a great deal of the vineyard from its original configuration of 33 acres of Chardonnay to its current configuration of 12 acres of Cabernet Sauvignon, 4 acres of Cabernet Franc, 12 acres of Merlot, 4 acres of Chardonnay, and 1 acre of Sauvignon Blanc (Barb wanted to make a little Sauvignon Blanc for her and her friends – 300 cases to be exact!).
Low Yields Make Better Wine
Our average yield is approximately 2.5 - 3 tons per acre; we drop a great deal of fruit in a typical year to maintain quality. Our vineyards are substainably farmed without the use of pesticides or herbicides. While we have not applied for organic certification, we follow organic farming practices with the exception of the type of sulfur we use for mildew control. The organically certified sulfur spray would require that we make 4 times as many passes with the tractor, which not only raises issues of expense as well as use of diesel fuel and soil compaction. Even though the binder in the sulfur spray we use is not certified as organic, it is biodegradable and has a negligible environmental impact.
Oak Knoll District Facts

The Oak Knoll District Appellation - sea level to 800' above sea level - is the 14th AVA in the Napa Valley. It consists of 15 wineries and 27 grape growers. Comprised of 8,500 viticultural acres - 3,500 acres planted to vinis vinifera - it is the second coolest appellation in the Napa Valley. During the growing season there will often times be a 12-15 degree difference between the Oak Knoll District & Calistoga (the northernmost Napa Valley appellation). With less rain than the rest of the Napa Valley, the Oak Knoll District results in drier, warmer soils and an earlier bud break. Fog from the South and East and cooling breezes from the San Pablo Bay all contribute to the long growing season, leading to the slow development of fruit that is essential for well balanced wines.

Our soils are comprised of the Dry Creek alluvial fan that has been drawn out of an ancient creek bed, that runs north to south from just south of Oakville to the Napa River. It is the largest alluvial fan in the Napa Valley. Because of the varied bedrock types drained by the fan, the base soil is very diverse with a combination of gravel and loam and a subsoil of clay. This soil type is similar to that of Chateau Petrus and Chateau Cheval Blanc from the Pomerol region of Bordeaux. The long and temperate growing season allows slow ripening of the fruit and elegant expression of varietal character.
Wide Spaced Rows Make Great Wine
We have a single vineyard divided into 8 irrigation blocks of 4 acres+ each. Our vineyard is planted with unusually wide spacing between rows. Our rows are 12 feet wide and the grape vines 8 feet apart. The new trend is to go to closer spaced vineyards - as close as 5 feet between rows and meter by meter between vines – which, according to those who practice this method of farming, has the vines fighting for the nutrients which in turn improves the quality of the berries.
However, while this denser spacing has produced greater yields, the quality may have suffered. The key reason for this is that the narrow spacing prevents the afternoon sunlight from reaching the grapes themselves - the canopy from the neighboring plant shades them.  Recent research has found that having sunlight on the grapes themselves helps develop the rich flavors and color found in the grape skin.
We have had many vineyard managers comment on our wide spaced vineyards saying “if you can afford it, this is certainly the better way to grow grapes”. Our grapes have a unique deep flavor to them that comes from our approach to farming. This approach, while leading to lower yields, both improves the quality of the grapes and the sustainability of the vineyard. And the proof is in the bottle.

The old adage, wine is made in the vineyard, certainly holds true at O'Brien Estate 
Hot air balloons fly over every morning
View from our catwalk above the tanks