“We’re just beginning to figure out where our good terroirs are,” Dr. Pogue said. “Most plantings have been driven by things like cost, or whether water was available, or whether it’s easy to farm.”

Some of the newer projects are most definitely not easy to farm. Ryan Johnson, a top vineyard manager, has recently planted a vineyard in 12 acres of rocky soils on the steep upper slopes of Red Mountain, including syrah, grenache, mourvèdre and tempranillo, an area Dr. Pogue calls “primo Washington terroir.” And three years ago, Mr. Baron of Cayuse planted a little more than two acres of syrah on another steep, rocky slope overlooking the north fork of the Walla Walla River, where the Walla Walla appellation dips into Oregon near the city of Milton-Freewater.

“It’s a crazy project, but it’s not about the money,” Mr. Baron said. “What drives me is the passion. Kevin gathered hundreds of samples to document the soils. It’s an incredible mix.”

Mr. Baron, who said the site reminded him of Côte-Rôtie, said he was inspired by legendary northern Rhône vignerons like Marius Gentaz and Noël Verset: “I want to do it exactly the same way, very traditionally, fermented in concrete tanks with lots of stems, and age in big old barrels with no new oak.”

Such projects are just the leading edge of the Washington wine business, accounting for only a minute fraction of the state’s production, which is dominated by behemoths like Chateau Ste. Michelle Wine Estates and Hogue Cellars.

They make good, sound wines, but the excitement for wine lovers is with smaller producers who are striving for something more distinctive, like Cayuse, Buty, Maison Bleue, Kerloo Cellars or Analemma in the Columbia Gorge. With Dr. Pogue’s work, the hope is that more and more producers will seek out the sort of cool-climate, steep-slope vineyards with the potential to make distinctive wines.

Dr. Pogue didn’t start out to study terroir. His original fieldwork involved studying the geological composition of the Himalayan foothills near the Peshawar Basin in Pakistan. But research in the area became too dangerous after the 9/11 attacks, so he shifted his academic focus closer to home. It helped that he had become a wine lover as well.