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PORTLAND, Ore. - Regular wine drinkers may turn up their well-cultured noses at the thought of synthetic corks or - gasp! - screw on tops for their favorite merlot or chardonnay, but a new study has found they can't tell any difference in the taste.

In a blind taste test conducted by researchers at Oregon State University's Food Innovation Center in Portland, wine drinkers couldn't tell the difference in the taste of the same wine, whether bottled with natural cork, synthetic cork or screw-top stoppers.

Yet a second study, by the same researcher, found that wine consumers who are confronted with a choice of stoppers are much less likely to purchase "screw-top" wine, considering it of inferior quality.

Clearly, the brown-bag image of screw-top wine will be difficult for the industry to overcome.

"Consumers simply couldn't tell the difference between identical wines with each of the three different closures," said Emily M. Jorgensen, an OSU graduate student working with the university's Food Innovation Center in Portland.

The wine industry is moving away from natural cork toward the use of synthetic cork and screw-on tops because of potential fungal contamination or "cork taint" through the use of natural cork.

In the study, Jorgensen researched groups of regular wine consumers to see if they could sense differences in the taste, smell and appearance of the wines, without knowing what kind of stopper with which the wine was sealed. She served identical wines from bottles with each of three types of closures - natural cork, synthetic cork and screw top.

"There was virtually no difference," Jorgensen said. "When they couldn't see the cork, they couldn't make a distinction." She investigated these consumer reactions using both a white chardonnay and a red merlot wine, both provided by Hogue Cellars in Prosser, Wash.

In a second experiment using the same two wines, Jorgensen tested another group of wine consumers to see how knowing the wine bottle closure type altered perceptions about a wine.

Tasting chardonnay from the three types of stoppered bottles, consumers said they were equally willing to purchase a bottle of wine with a natural or a synthetic cork and pay the same price for either.

Wines with screw tops, however, ranked low in people's minds. When presented with the same chardonnay, but from a screw top bottle, the wine drinkers said they had the impression that the wine was of lower quality and said they would be less willing to purchase it.

And they said that they weren't willing to pay as much for it.

When it came to the red wine (merlot), consumers said they preferred the wine from a naturally corked bottle to either a synthetic cork or screw top. And they were willing to pay more for it.

Natural corks have been used to close wine bottles and jugs for centuries. But years of studies have shown that naturally corked bottles just don't keep wine in good shape as well as synthetic corks or screw tops.

"From 3 to 20 percent of wines with natural corks suffer from 'cork taint,' a product of fungal contamination of the cork that gives a moldy or wet cardboard flavor to even the finest vintage," Jorgensen said.

Jorgensen's study reconfirms that there is a commonly held, but mistaken belief among the American wine drinking public that a "real" or natural cork lends a wine a certain high quality that a screw-top or plastic cork just doesn't muster.

"Millions of dollars worth of wines are lost per year from cork taint and other problems associated with natural corks and many in the wine industry are making the transitions to synthetic corks or screw tops," she said. "But there's a major hurdle to overcome - consumer acceptance. A sommelier opening a $100 bottle of wine with a twist of a metal screw top just doesn't go over with many discerning consumers." OSU and Oregon Department of Agriculture jointly run the Food Innovation Center in Portland. The center assists food producers, marketers and entrepreneurs with all types of food research from concept to market, as well as trains tomorrow's food researchers. The staff includes food research scientists, technologists, engineers, economists and business experts.