Sumac

Sumac is a coarse, deep red powder with a tart, fruity bite. Think lemon zest without the juice, with a little tannic grip behind it. The smell is faint and slightly resinous until it hits warm food or oil, then it opens up. It is sour first, mildly salty second, and it never turns bitter the way citrus peel can.

Use it where you would reach for a squeeze of lemon but do not want the liquid. Scatter it over roast chicken thighs as they come out of the pan. Toss it with sliced raw onion and parsley to serve alongside grilled lamb. Stir it into yogurt with garlic for a dip. It works on chickpeas, on fried eggs, on charred eggplant, on white fish, on cucumber and tomato salad, and on flatbread brushed with oil before it goes in the oven. Mixed with sesame seeds and dried thyme it becomes a standing table condiment.

Start with about a teaspoon for four servings and add more at the end. Sumac dulls with long cooking, so most of it should go on late or raw. A heavy pinch over a finished plate does more than a tablespoon stirred into a stew. Keep the jar closed, dry, and away from the stove; moisture makes it clump and heat flattens the sour edge. It stays bright for roughly a year.

• 2 oz (57g): enough to test it on a few dinners and decide if it earns a spot.
• 19 oz (539g): the size for a cook who finishes plates with it most weeks.
• 70 oz (1984g): for catering, a cafe line, or a house where sumac goes on everything.
• Decant from the 70 oz jar into a smaller shaker so the bulk stays sealed.
• Add at the end of cooking, not the beginning.

If you are unsure, the 2 oz jar answers the question in a week of cooking.