Tannins are polyphenols from grape skins, seeds and oak barrels that give red wines their characteristic astringency. At a chemical level, tannins bind to proteins and precipitate them — exactly what happens in your mouth when you drink a young Barolo. Protein in food does the same: it binds tannins and neutralises astringency. Red meat, especially grilled or roasted, is therefore an ideal partner for tannic wines such as Cabernet Sauvignon and Nebbiolo. Without enough protein — for example with vegetables or fish — tannins can feel drying and bitter.