Some years ago the admired New Zealand producer Vidal, sister company to Villa Maria in George Fistonich’s empire, the biggest independent wine company in the country, sent me a case of wine. Normally I demur if anyone sends me more than two bottles of the same wine (see our statement of ethics), but this unsolicited dozen was different. It contained 12 bottles of exactly the same wine, Vidal Estate Reserve Cabernet Sauvignon 2000 Hawke’s Bay, but half of them were stoppered with screwcaps and half under natural cork. They sent them explicitly asking me to compare bottles of...