Serving

The old rule - white chilled, red at room temperature - comes from a time when a room was about 16°C. A heated house today sits at 21-22°C, and at that temperature most reds taste flabby and alcoholic. The fridge runs at about 4°C, which mutes a white almost completely. So both halves of the rule are now wrong.

Both errors have the same fix, 20 minutes before you pour: put the red somewhere cooler than the room, and take the white out of the fridge.

• Cold suppresses aroma - volatile compounds need warmth to evaporate. Over-chilling makes any wine smell of less.
• Cold accentuates tannin and acid - a chilled red tastes harder and more astringent than the same wine warm.
• Warmth accentuates alcohol - above about 18°C, ethanol starts reading as heat and spirit rather than as body.

This gives a general rule: the more tannic the wine, the warmer it wants to be, up to a ceiling of about 18°C. The more aromatic and delicate, the cooler - but never so cold that it stops smelling of anything.

The industry sells a different glass for every appellation, and the evidence for most of those distinctions is thin. Three things do genuinely matter.

• Size - big enough to swirl a normal pour without spilling. This is the main one.
• A tapered rim - narrower than the bowl, so aroma concentrates rather than dispersing.
• Thin, plain glass - thick rims interfere with the flow of wine, and cut crystal patterns make it impossible to judge colour.

One decent universal glass covers everything from Riesling to Barolo. The genuine exception is sparkling wine, where a flute preserves bubbles at the cost of aroma - which is why serious Champagne is increasingly served in a white wine glass instead.

Two entirely different operations that share a name.

Note that the two goals are opposites, which is why doing the wrong one to an old wine can flatten it within the hour. When in doubt with something mature, open it and pour a glass; if it improves in the glass, it will improve in a decanter.