92 points
Vineyard Brands sales rep Emmanuel Lemoine's view in New Zealand during his 
Jay Schiering of McCarthy & Schiering Wine Merchants in Seattle with 
Glazer's Domaines & Estates staff in Kansas City tasting Jaboulet Perrin with wine producer
Natural cork
Natural cork closures have a centuries-long heritage; however, they allow for a bottle of wine to be "corked" as the saying goes. A "corked" bottle has a musty smell and taste that stems from TCA (2,4,6-Trichloroanisole) - a substance used to sanitize the natural cork prior to bottling. The result is a flat, moldy flavor devoid of fruit-filled taste and aroma. It is estimated that about 5-10% of wines available on merchants’ shelves are "corked."
Synthetic Corks
Synthetic corks, derived from plastic, appeared to be a viable alternative to traditional corks. However, their track record has been tarnished due to their inability to keep oxidation at bay for any real length of time, significantly decreasing the shelf life of a wine and short-changing the maturing process of select wines.
Screw Cap
Screw caps provide the best seal for bottled wines, and eliminate the "corked" and oxidation problem in one fell swoop. Hogue Cellars completed a 30-month study comparing natural and synthetic cork closures with the Stelvin screw caps, their findings suggest significant benefits in utilizing screw caps over either natural or synthetic cork closures. While, screw caps do diminish the drama and romance of bottle opening it is well worth the sacrifice to ensure a taint-free wine that offers consistent aging, maintained flavor and freshness with optimum quality control.
The Stelvin screw cap appears to be the industry’s cap closure of choice. With producers such as Hogue Cellars , Beringer, Bonny Doon, Penfolds and many others utilizing the Stelvin screw cap closure for wines of all price ranges. We are sure to see this trend take hold as winemakers and wine enthusiasts alike place a higher priority on overall quality and less on "corked" tradition.
Read the complete article: http://wine.about.com/od/storingwines/a/Screwcaps.htm
