When I peruse the wine aisle these days, I can't help but notice more and more screw caps. Can this really be happening? Californian, German, Australian and 80 percent of wines from New Zealand are being bottled with twist-off or Stelvin closures; even French wineries are getting in on the act. What is going on?

The trend can likely be attributed to industry concern about "corked" wine — wine that is tainted by 2,4,6-trichloroanisole, or TCA, or other chemical compounds that result from complex interactions between micro-organisms and various pollutants. TCA, which is extremely potent, can come from a bad cork or from inside the winery itself if barrels, walls or floors are moldy or contaminated. Industry estimates on corked wines range from 1 to 2 percent (this from the cork industry) to up to 15 percent of wines (this from Wine Spectator magazine).

So how can you tell if a wine is corked? As with everything else, people's perceptions of corked wine can vary greatly. But there are telltale signs. A corked wine will have a musty smell similar to that of wet newspaper or cardboard. Also, the fruit flavors in the wine may be muted. In a restaurant, if you believe a wine you are served is corked, ask the wine manager for a second opinion. Also, double-check the glass for soap residue, as that can impart the same characteristics as a corked wine. Many times, wine professionals rinse out the glass with a small pour of wine before tasting it.

Wineries are justifiably concerned about corked wine. If one of their customers happens to get a tainted bottle, that person may very likely think the wine itself is bad and never purchase it again. Odds are that most wine drinkers will come across a corked bottle once in a while. The use of screw caps greatly reduces the likelihood of coming across a corked wine.

Still, most people equate screw-tops with cheap jug wine. But does this form of closure really deserve this stigma? In 1997, a famous high-end winery, PlumpJack, bottled half of its reserve cabernet in cork and half in twist-offs. The wine sold out immediately in both formats, and tasters say they cannot tell the difference between the two. No bottles of the screw-cap version have been returned to the winery because of TCA.

But let's be honest: You may buy a screw-cap bottle for yourself, but would you be bold enough to give one as a gift? Will restaurants begin serving wine with screw caps anytime soon? How will the sommelier present this wine to a table? And what about the anticipation and ceremony that surrounds the pulling of the cork from a bottle of fine wine?

All this remains to be seen as more wines will be showing up with this new closure. You may already have been surprised to see the new vintage of an old favorite sold with a screw cap.

But let's give the screw cap its due. For a start, with a screw-cap bottle, you don't have to fumble with a cork puller any more, or remember to bring one on a picnic. That's a real plus for that impromptu bottle of wine. And now that corkscrews are banned from airline carry-on bags, with a screw cap you could still enjoy a bottle when traveling. Screw-capped wines can be stored upright without your having to worry about the cork drying out. And perhaps best of all, if you don't finish a bottle of wine, it is a cinch to reseal it.