Riesling, an off-and-on success in Oregon, has started to shine brighter in recent vintages. Of the 40 Oregon Rieslings to receive scores of 90 points or higher (Outstanding on the Wine Spectator 100-point scale), 26 have come since the 2010 vintage.

What's causing this? Partly, it's the emergence of wineries concentrating on the varietal, most notably Trisaetum (first vintage 2007). James Frey's operation makes eight different Rieslings, sorted by vineyard source and whether they're dry or off-dry, and no Chardonnay or Pinot Gris, Oregon's signature white wines.

Most Oregon Rieslings tend to correspond to typical kabinett or spätlese wines from Germany, and Trisaetum's dry style follows the contours you might expect from a Mosel or Nahe. Harry Peterson-Nedry at Chehalem produces consistently fine Rieslings that lean more to a dry Alsace model, though usually with more forward fruit. Chehalem also vineyard-designates Rieslings.

To learn about these wines, Frey and Peterson-Nedry put together a three-by-three tasting that also included Brooks Vineyard, another Riesling advocate. Each contributed a barrel of pressed juice from the vineyards next to their wineries—Trisaetum on sedimentary soils in Ribbon Ridge, Brooks on volcanic soils in Eola-Amity Hills and Chehalem on loess soils at Corral Creek in Chehalem Mountains. Each fermented the juice dry. We tasted the wines in Trisaetum's conference room, complemented by takeout sushi.

"You'd be hard pressed to take any two and say, same wine," Peterson-Nedry said after we tasted them all. "That's what Riesling is so good at."

Indeed, the three wines made from Brooks' grapes showed a distinct toasted walnut aromatic, although they had very different textures and structures. Brooks' own wine had a raw edge while the Chehalem version was prettier, more fresh and sleek, and Trisaetum's softer, with impressive length.

A lime note emerged on the Corral Creek wines, the Brooks showing more elegance and pear, Chehalem's tangy acidity with a distinct glint of star fruit, Trisaetum's less obvious, lighter.

A fresh-cut pear character ran through the three Ribbon Ridge wines, with Brooks' very dry and mouth-tightening but hinting at apricot, Chehalem's fresh and open with a floral note, and Trisaetum's balancing the elements most perfectly.

"The important thing is there's a serious community working on Riesling," said Peterson-Nedry, a veteran of nearly 30 vintages. Among other outstanding Rieslings in recent vintages are those from Alexana, Argyle, Hyland, Big Table Farm, Harper Voit and Elk Cove.

"It hasn't always been that way. It used to be a cash-flow wine, but it's becoming something worth aging and keeping."

Frey noted that he budded over Pinot Gris to Riesling in his Wichmann vineyard in Dundee Hills. "That should be a metaphor for Oregon. Let's lop off the Pinot Gris, and graft on Riesling," Peterson-Nedry laughed. "We still grow the same amount of Gris as we did 14 years ago, but Riesling …," he made a gesture like a plane taking off.