For many years now there has been a certain stigma associated with wines having a screw-top closure. They were felt to be slightly inferior to the overwhelming majority of wines who followed the centuries old tradition of using the cork as a seal. The problem with the cork is that it is a living organism and can change over time. Sometimes these changes are not for the better and they result in cork “taint” which has ruined many a bottle of good wine. Some claim as many as 2% of all wines are contaminated by bad corks. In an effort to solve the problem, some wineries began using synthetic corks while others tried the screw cap.
Well, if your image of wines with a screw cap was right up there with boxed and bagged wines you can forget that association. An article in the current issue of Wine Spectator Magazine (May 31, 2010) by Harvey Steiman reports on the results of a ten year study by the Australian Wine Research Institute (AWRI). “The trial used 14 different closures including corks, synthetic corks and screw caps on thousands of bottles of the same wine, a 1999 Clare Semillon made at Leasingham. Once a year the testers would open bottles to analyze and taste a range of wines in the lab.”
The picture on the left shows the wines at various points during the testing from 2 years on the top to 10 years on the bottom row. The wine on the far left in each row is the bottle of Semillon with the screw cap closure. Researchers reported that only the screw cap bottles were wonderful to drink after ten years. Most of the bottles with other closers were “completely undrinkable”.
So much for pre-conceived notions.