What Wine Does in Your Mouth

Before it is an appellation or a label, wine is a liquid that does something in your mouth. From the first sip, four sensations stand apart, as long as you have a word for each.

Acidity gives wine its lift. Without it, a wine feels flat and heavy; when it is bright, the wine feels fresh and makes you want the next sip. You spot it by your saliva: the more it flows, and the longer, the higher the acidity.

Tannin is felt mostly as touch: it dries your gums and makes them grip, which is called astringency. It often comes with a touch of bitterness. It comes mainly from the grape's skins and seeds, and passes into the wine when the skins soak in the juice. That is why it is found mostly in reds: most whites are pressed without long skin contact.

Body is the weight of the wine on your tongue. To place it, think of three liquids: water, skimmed milk, whole milk. Alcohol is felt after the sip, as rising warmth. It comes from the grape's sugar, which fermentation turns into alcohol: the sweeter the grape, the warmer the fully fermented wine. The two often go together: a more alcoholic wine often feels fuller.

You now have a word for each sensation, and each leaves a sign you can notice. Go over them, then practise: recognise a sensation from its sign, and say which of two grapes pushes it furthest.

Sensations do not add up at random. A classic scheme, from the oenologist Émile Peynaud, puts them on a balance: on one side acidity and tannin, which harden a wine; on the other alcohol and sweetness, which soften it. A wine feels balanced when nothing sticks out. It is a guide, not a measurement.