Randy Dunn was up on Howell Mountain before it was Howell Mountain. That is, back when only Dunn and a few others realized the potential of this lofty environ (2,000 feet above sea level) as a great grape growing region. Even though Dunn, the owner and winemaker at his eponymous Dunn Vineyards, has been growing grapes in these eastern hills above St. Helena since 1979, he says he still doesn’t know what differentiates a Howell Mountain wine from a Diamond Mountain wine.

That’s because Dunn, one of the most forthright vintners you’ll ever encounter, thinks that the panoply of technologies available to winemakers and vineyardists has muddied the waters. It’s mucked up any hope of terroir expression in wines grown in this country.

Dunn, who was the winemaker at Caymus from 1979 to ‘85, bought 14 acres the year he started at Charlie Wagner’s Rutherford winery. At the time, only Bill Smith and his La Jota Vineyard were producing wines on Howell Mountain. There were only a few others such as Mike Beatty, Frank Stout and Bob March (who would later sell his property to Duckhorn) and Summit Lake Vineyard, who were even growing grapes here.

Dunn produces two Cabernet Sauvignons most from his 35-acres of vineyard and from a vineyard he leases, all on Howell Mountain. They sell for $70 and $65 a bottle, and both are built to age.

The outspoken Dunn, in this interview with Appellation America’s Napa Valley Regional Correspondent, Alan Goldfarb, rails against high-alcohol wines that are in vogue; and acknowledges that his finished wines come in at under 14 percent because he dealcoholizes his wines via reverse osmosis. In addition to talking about his own wines and vineyards, Dunn spoke about the AVA’s distinctive climate. Along with La Jota’s Smith, Dunn was instrumental in getting Howell Mountain to be named the Napa Valley’s first sub-region.