Within the European Union there are requirements as to the standard sizes for bottles. These standards have been adopted by the rest of the wine world. A normal wine bottle holds 0.75 liter, and a half bottle 0.375. A magnum bottle, prized by connoisseurs because the wine ages better, is 1.5 litre. The convenient amounts of I liter, 0.25 and 2 litres are also permitted.

The standard bottle held 75 cl long before this was standardized by law. Why? In the time when all bottles were blown by individual craftsmen, this size was what a glassblower could form with one breath.

Decanting is usually associated with aged red wines and port, which have formed sediment over the years. Decanting (pouring the wine carefully into a carafe) ensures that the sediment remains in the bottle. But decanting can also be good for young wines, which are sometimes harsh. In this case the wine is exposed to oxygen to soften the taste.

Do take care, though — too much exposure to the air can lend an unpleasant and oxidized taste to a wine, especially more mature, noble wines. Conventional wisdom in Wine 101 guides for a long time was to open the wine an hour before serving to let it ‘breathe’, but research has shown that the surface area in the neck of the bottle is much too small to be effective. Decanting into a carafe is often the best method for serving young wines.