Cooler than you think for reds, warmer than you think for whites.
Most home-served wine is poured at the wrong temperature. The conventional cues — “room temperature” for red, “chilled” for white — were calibrated for European homes in the early 20th century, where rooms were cooler and refrigerators colder. Both numbers have drifted.
Working ranges
Light reds (Pinot Noir, Beaujolais, Loire Cabernet Franc) are at their best between 13 and 15°C. Medium-bodied reds (most Bordeaux, Sangiovese, Tempranillo) at 15 to 17°C. Big tannic reds (young Bordeaux, Barolo, Napa Cabernet) at 17 to 18°C. None of these wines should be served at the 22°C that most modern living rooms hover at.
White wines and Champagne are usually served too cold. A serious white Burgundy or aged Riesling at 6°C is muted; the same wine at 11 or 12°C will reveal twice as many aromatics. Champagne benefits from sitting in the glass for a minute before drinking, especially mature bottles.
Practical fix
For reds: take them out of a 22°C room thirty minutes before serving and put them in a 16°C cellar or a refrigerator door. For whites: take them out of the fridge fifteen minutes before pouring. The wine warms at roughly 2°C per ten minutes outside the fridge.
If you only remember one rule: cooler than you think for reds, and warmer than you think for whites.