How Sullivan Rutherford Estate Made the Best American Cabernet Sauvignon of the Year

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Seeking a spot in Napa Valley to grow grapes and make wine, Sullivan Rutherford Estate founder James O’Neil Sullivan and his wife, JoAnna, purchased a particular 26 acres of land in the heart of region in 1972, on the advice of André Tchelistcheff, a man referred to as the dean of American winemaking. The flagship bottlings of the estate, J.O. Sullivan Founder’s Reserve Merlot and Cabernet Sauvignon, score highly with critics year after year and are snapped up by in-the-know collectors, but they somehow fly below the radar of the wider wine-loving public. As we tasted through samples during the past year, we marked the 2021 Founder’s Reserve Cabernet Sauvignon as one to watch and were not surprised that after our final Best of the Best blind tasting, we’d crowned it the Best American Cabernet Sauvignon of the Year. But after we gave it an honor, we wanted to dig further into how this great wine came together.

The Sullivan Estate vineyard is on the valley floor at the northern edge of the Rutherford appellation, where predominantly gravel, sand, and loam soils provide excellent natural drainage and result in reduced vigor and low yields in a good year; 2021’s was reduced by 30 percent.  Hailing from a vintage marked by sporadic heat spikes, Sullivan Rutherford Estate 2021 Founder’s Reserve Cabernet Sauvignon was made with smaller-than-usual grapes, which had a higher skin-to-juice ratio that allowed winemaker Jeff Cole to “push fermentation and extract more phenolics,” resulting in a concentrated, powerful wine. “This vintage really highlights the character of our Rutherford estate, with its dark fruit, savory undertones, subtle dried herbs, and signature minerality that define both the site and the broader appellation,” he says.

Once grapes arrive at the winery, Cole does a seven-day cold soak with three pump overs a day. He then raises the temperature to 85 degrees Fahrenheit, inoculates with yeast, and reduces pump overs to two times per day. When the wine is completely dry, the temperature is reduced to 70 degrees Fahrenheit and the wine sits on its skins for four to six days. After that, the free run juice is drained to another stainless-steel tank and kept warm for a week before being moved to 80 percent new French oak barrels.

Rather than opening each barrel about once a month to top them off and check sulfur-dioxide levels, Cole utilizes a method he calls “hard bunging” to create a more concentrated, extracted wine. This is when the magic happens. “The idea came to me when I started thinking about how much wine we lose to evaporation,” Cole says. “I thought, what if I could create a hermetically sealed environment that allows for evaporation, ultimately concentrating the wine?” Under normal circumstances, as wine evaporates from both natural conditions and regular sampling it creates headspace, which allows the wine to come in contact with oxygen. Most winemakers use silicone bungs on their barrels, which form a good seal on them, but are easy to remove so that barrels can be refilled to the top to mitigate the headspace and oxygen contact.

Cole’s hard-bunging protocol takes a very different approach. Instead of regularly opening barrels, he uses wooden bungs and rotates them so they swell and fully enclose the barrel, creating a hermetically sealed, anaerobic environment. “The only oxygen exposure comes from the natural micro-oxygenation that occurs through the barrel staves themselves, not from opening the barrel,” Cole says. “This process helps preserve freshness, reduces the risk of volatile acidity, and ultimately results in wines that are more vibrant, stable, and concentrated.” This is a different philosophy than most winemakers use, “one based on minimizing oxygen and maximizing the natural concentration that comes through controlled evaporation,” he says.

Through trial and error, he found six months to be the “sweet spot,” offering enough time to maximize evaporation without causing the wine to become reduced. “Every six months, I reopen the barrels, check sulfur levels to protect against microbial activity, and top them off with wine that has undergone the same process,” Cole explains. He reseals and repeats the cycle with each wine for a total of 18 months, allowing for three full cycles of evaporation and concentration. The final blend is made prior to the last sixth-month sequence so that the wine comes together in the barrel until he is ready to bottle. Cole believes that most Napa wines are already excellent, but the challenge to winemakers is how to push them even further. For him, it is about finding small, incremental gains to bring out the best, and this process—which he doesn’t think anyone else in Napa or even the world is using—results in denser wine that is rich in color, tannin, and the phenolics that give red wine its depth and complexity.

Some credit must go to Rutherford itself; Cole acknowledges the daily coastal breeze coming up from San Pablo Bay, which cools the vineyards down and helps retain acidity along with hot, sunny days in the center of the valley to bring the perfect combination of ripeness and freshness to the wine made here. Tchelistcheff himself coined the term “Rutherford dust” at nearby Beaulieu Vineyard over 30 years before he convinced the Sullivans to purchase their estate here. Cole thinks that the phrase was meant to capture the unique, old-world qualities you only get from fruit grown in Rutherford. “It’s that dark, savory profile, the dried herbs, the minerality, the bitter baking chocolate, the earthy undertones,” he says. “These are the true hallmarks of Rutherford Cabernet.”

Cole admits that there is a touch of “secret sauce” in the Sullivan Rutherford Estate 2021 J.O Sullivan Founder’s Reserve Cabernet Sauvignon: the 11 percent of estate-grown Petit Verdot that is blended in. “While most winemakers use Petit Verdot to boost color or structure, I already get plenty of structure from my Cabernet. What it brings to this wine is a plushness, an added layer of depth and complexity,” he explains. He says it amplifies the dark, savory notes that Rutherford and the estate are known for. “I like to say I want to make the most Rutherford Cabernet in Rutherford, and the Petit Verdot helps me do exactly that,” he says. Surrounded by high-profile neighbors like Inglenook, Beaulieu, Realm Cellars, and Quintessa, it takes a lot to stand out, but between hard bunging and secret sauce, Cole made what we consider the best American Cabernet Sauvignon released in the past year.

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