What ageing does to wine

Primary fruit fades. Tannins polymerise into larger molecules and feel softer. Colour changes — reds move from purple towards brick, whites deepen towards gold. Tertiary aromas develop: leather, mushroom, forest floor, honey, dried fruit.

The trade is intensity of fruit for complexity of character. Whether that is an improvement is a genuine matter of preference, and plenty of people prefer young wine.

The wines that age well have high acidity, high tannin, or high sugar — often more than one. That is why Riesling, Nebbiolo, Bordeaux and Sauternes last and most wine does not.

The great majority of wine made in the world is intended to be drunk within two or three years, and keeping it makes it worse rather than better.

Ageing is not a quality signal. An expensive wine built for early drinking is not failing by being ready.