Orange zest is the thin, aromatic, colored outer layer of the orange's rind, grated or peeled off without the bitter white pith beneath it; this makes it milder and more purely citrus-flavored than the fuller orange peel, which can include some of that pith. It is a common flavoring in baked goods, custards, and puddings, and also appears in savory marinades, vinaigrettes, sauces, and rubs across Mediterranean, Middle Eastern, and Asian cooking. Use a fine grater, zester, or vegetable peeler to remove just the colored layer; grating too deeply into the white pith gives an astringent, bitter taste. Dried zest keeps well and retains most of its flavor for later use.