How long can a red wine age in a bottle with a screw cap? A friend and I each purchased a case of 2007 Strong Arms Shiraz a couple years ago. When we first bought the cases, the wine was well balanced. Now, every time we open a bottle, it tastes very harsh and is not drinkable. I'm afraid we are going to have to use it for cooking! Raeann Koerner
Answer From Expert Roger Bohmrich MW
The subject of closures, including the relative merits of various types of corks and screwcaps, is very much a hot topic in the wine world. The choice of closure rests with the winery, and there are differing opinions as to the benefits and disadvantages of natural, technical and synthetic corks and screwcaps. Studies have examined the question of taint (cork-related and other) and now are focused on the transmission of oxygen with each closure type. Scientific research indicates - despite strongly held opinions to the contrary - that aging of wine in bottle is an anaerobic process; in other words, it occurs primarily without the influence of oxygen. Studies of how wines under screwcap age have been undertaken in Australia, and while the results are somewhat complicated they appear to confirm that wine does evolve and can improve as it might with a natural cork. Coming back to the Australian wine you have, if by harsh you mean astringent, the taste is likely to be unrelated to the closure and could come from the tannins. If so, this may change chemically with further aging, and the wine will become smoother. Or do you mean sharp and acidic? To compensate for low natural acidity, winemakers in Australia may add acidity, and sometimes this can be excessive. It is true that winemaking needs to be adjusted if screwcaps are to be used, particularly with respect to the addition of sulfur dioxide, but in this instance the culprit could be the wine itself.
