The reason for his disgust was, of course, because corks have a tendency to become infected with TCA. As I wrote in a previous blog, TCA is a chemical compound that makes a wine smell and taste bad and comes from cleaning the cork with chlorine or unclean winemaking practices. This was an especially problematic issue in the 1990s, when possibly up to 10% of wines were infected with TCA. Things have got a lot better since then as the cork industry has worked hard to remedy the problem, but there's still a 2-5% chance of a wine being faulty, whereas with a screwcap that's nearly zero.
So why doesn't everyone use a screwcap?The downside to screwcaps is that they arguably don't allow a wine to age as well as a cork does. A cork lets small amounts of oxygen to permeate into the bottle, allowing the wine to breathe, develop, and mature. A screwcap, again arguably, does not allow a wine to develop the same complexity as it is completely airtight.
Many wineries are experimenting and coming to different conclusions. A few years ago, I visited the Andrew Will winery in Washington and the maverick, charismatic owner and winemaker Chris Camarda kindly poured me two versions of the 2008 Sorella, one of the great wines of the US. One bottle had been stopped with a cork (which is how the wine is sold) and the other closed with a screwcap. The differences were subtle, but the screwcap bottle was fruitier while the cork bottle felt more integrated and complex, with spicier and more oak flavours. That confirmed my impressions that a bottle stopped with a cork ages more gradually and complexly than with a screwcap. That was again confirmed by the recent decision of a leading Chablis producer, Laroche, to switch back to cork for their Grands Crus, having used screwcap since the mid-2000s but feeling that the wines were not ageing as gracefully as they would have wished.