Sumac is the common name of the plant Rhus coriaria and its dark purple-red berries; dried and used whole or ground, they lend foods a fruity, sour, astringent flavour. A staple of Middle Eastern cooking, especially Lebanese cuisine, it brightens salads, grilled meats, and the spice blend za’atar with its lemony tartness. Alternative names include sumaq, sumach, shumac, and Sicilian sumac. Its acidity comes from organic acids and tannins, and it must be sourced free of adulteration, since its deep colour invites substitution with inferior material.