His had all the silky mouthfeel, power, and persistence of any XO or older brandy, but a surprising sweetness, too, from the fruit flavor that characterizes all his brandies. Also, the XO had life that continued on the palate and as the brandy opened up in the glass. Other XOs have plain power, and become duller as they stand. Another worthwhile gift is the right glass. The wide base encourages too-fast evaporation of the alcohol, and the narrow top concentrates the fumes, delivering heat to the nose and palate at the expense of the subtler scents and flavors that should prevail.
Professional tasters use smaller, narrow glasses with only slightly bulbous bases and flared rims.
When I rented glasses recently for a cognac evening, the only reasonable alternative was a small champagne flute. The outwardly curved rim makes the liquor first hit the front of the palate, which registers sweetness, and then the back, where depth and roundness are felt. His wife certainly doesn't like it. However unappetizing, this has its own logic. Many wine drinkers do no more than rinse their glasses, because detergent residue spoils the taste of wine and liquor.