Over the last few weeks, I had some interesting experiences drinking mature red wine from different types of bottles and bottle closures and the outcomes were different from what the press want you to believe.
In relation to white wine, some results are pretty clear. Natural cork is not a good closure. Even if there is no fault, cork often dulls the wine. Other closures are clearly better. It remains to be seen how often chemicals leak from screw caps.
Red wine is more complicated in this regard. The other day, I drank a 2005 Mt. Langhi Shiraz under screw cap.It was no different from the first year after bottling - no maturing effects whatsoever. I find this disappointing. If I open an eight year old bottle, I am seeking complexity of flavour, a mellowing of the tannins etc.
Magnums are priced at a premium in Australia (in contrast to many countries), mainly because the surface area of the cork is less relevant than in normal bottles, and the wines should mature more slowly, thereby offering more value. Generally speaking, I find this to be true. But are Magnums becoming superfluous with screw caps on the scene, other than for celebratory reasons? Not in my experience. The 1996 Wynns I reported on was still fresh, but was also maturing - just slowly. I have no doubt there is a minuscule air exchange occurring under cork, whereas there is none under screw cap.
The regular size 1998 Cullen under cork was also perfect. There was nothing wrong with the cork, and the wine had developed beautifully.
So, what does all this mean for me? Very simply,
1) The move to screw caps is important, because it is a wake-up call to cork manufacturers. They must improve quality control and I expect faults to reduce over time.
2) Opening a corked wine bottle is very disappointing, in particular if I had stored the wine for many years. However, this does not happen very often, maybe in 2-3% of bottles. Leading winemakers establish special relationships with quality cork producers to get better quality control.
3) Cork allows a quality wine to develop flavours through aging, which screw caps do not necessarily do. I have not enough experience with other closures. The glass closures used by Henschke could be interesting.
4) Some wines seem to mature nicely under screw cap, for example Moss Wood. It happens, just more slowly. But others do not.
In conclusion, and perhaps paradoxically, I am somewhat weary about buying a red wine I want to age under screw cap (Penfolds?), while I am happily buying one under cork if the cork management is good.