Frustratingly, I recently opened a bottle of Le Grand Prebois Blanc, and it was faulty. Instead of smelling like peaches, almonds and marzipan, it smelt much like dirty wet socks. The surprising thing about this was: Le Grand Prebois Blanc is sealed by a screw cap, shouldn’t it be more immune to bottle faults?
Wines stoppered under screw caps will not be “corked”, that musty effect that occurs when chlorine, mould and cork meet to ruin an otherwise lovely beverage. Screw caps have their own, if less common, flaws. Because screw caps offer a tighter closure than cork, there is a greater chance of a wine being “reduced”, ie, not having enough oxygen in the bottle. A reduced wine can smell of cabbage or rubber, not great for enjoying!
That said, there have been enough studies now that seem to point to screw caps as a superior preservative of wine, both over time and as a resistance to shorter term faults (see Jamie Goode’s Wine Anorak site for more). On account of the newness of screw caps, we don’t have anything other than laboratory simulation of very long term bottle ageing under caps, though premium wine producers like Bonny Doon in California are optimistic and pleased with early results.
The largest complaints against screw caps seem to be customer perception, followed by adherence to tradition. Personally, I’d rather increase the chances that my wine comes without stopper fault, and to that end my preference must be for screw caps. In the least case, it is worth noting that, increasingly, screw caps are not necessarily a sign of a lower quality wine.