Twist-offs, aka screwcaps, prevent wines from suffering cork taint. But Harry Peterson-Nedry believes that's only one advantage. "In 20 or 30 years we're going to say that other benefits are even bigger," he says.

We were pouring 10 vintages of his Chehalem Pinot Noir Willamette Valley Three Vineyard Pinot Noir to see how well they have aged. No suspense, every single bottle was free of any kind of taint, and the older vintages, back to 2004, had developed extra layers of aromatics and flavors that come with time in the bottle.

Peterson-Nedry was one of Oregon's early adopters of the closure, frustrated that so many bottles he had worked so hard to perfect went bad because of cork taint. Not just the moldy, mildewy, crushed-aspirin "eww" of full-blown corkiness but the stripping of freshness and fruit from lesser concentrations.

The bonus? Twist-offs also prevent oxidation. "Not only does that keep the fruit [flavors] from disappearing," Peterson-Nedry explains, "without oxidation you don't use up the smaller amounts of sulfur dioxide we add these days. You have something left to fight the little bit of brett (another spoilage organism) that's in all red wines."

He has the lab results on all the wines we tasted to prove it, too.

Australia and New Zealand have shown that Rieslings and Hunter Sémillons age gracefully under twist-offs. Chardonnays, too. But what about reds? A cork that lets in air not only oxidizes white wines but actually slows the main benefit of aging reds. Softening tannins requires an absence of oxygen.

Experienced tasters often complain, however, that wines under twist-offs don't develop the aromatics and flavors they expect with age. They say the wines never change. They just stay young and fruity.

That one has always puzzled me. In my experience, wines aged under twist-offs develop along exactly the same track as those under a perfect cork, one that seals completely. These are the bottles with no discernible ullage, the ones that taste gorgeously fresh and vibrant after 20 or 30 years as they soften their textures and develop extra nuances.

Peterson-Nedry's theory, and I agree with it, is that those who drink a lot of aged wines expect oxidation's toasty, nutlike flavors to dominate, not to mention the presence of leathery, gamy notes that come from brettanomyces. They expect the fruit to diminish. They mistrust old wines that still glow with berry, cherry and plum flavors.

In Chehalem's all-twisty vertical, older wines showed freshness and vitality, presence and grace, and they reflected their vintages precisely. The 2007 picked up dried orange peel notes, the 2006 suppleness and purity through a harmonious finish. 2005's chewy tannins may need further aging, but the 2004, fully resolved, rolled out its generous fruit and mint flavors with elegance.

"I wanted to test whether these wines were stillborn and never changed," says Peterson-Nedry, who has shown this vertical to the trade in six cities so far, to positive reviews, and plans at least another half-dozen showings. "But we're pleased that we're getting the same flavors and aromatics that we want, and none of those we don't want."

"We can look at those wines without oxidation masking everything else."

And that's the really big deal about twist-offs.