Ingredient

Sumac

Sumac is the dried, ground fruit of a shrub, and it is sour — genuinely, mouth-wateringly sour, from malic and citric acid, the same acids that make apples and lemons sharp. It is the only common way to add real acidity to a dish as a dry powder, and that makes it more useful than its niche reputation suggests.

What it is, and how it differs from lemon

The berries of Rhus coriaria are harvested, dried and ground, usually with a little salt. The result is a coarse, deep brick-red powder with a slightly damp, clumpy texture and a fruity, tannic sourness.

It is not a lemon substitute, exactly. Lemon juice is bright, volatile and wet — it lifts a dish and it dilutes it. Sumac is dry, deeper, tannic and slightly astringent, with a fruity, almost berry-like note underneath the sourness. It adds acidity without adding liquid, which is the practical reason to reach for it: you can sharpen a dry rub, a dip or a finished grill without making anything wet.

It is also a colour. A dusting of sumac over pale hummus, white onion or grilled chicken does as much visually as it does on the tongue.

Where it belongs

• Over hummus, labneh and yoghurt dips, with olive oil. Almost obligatory across the Levant.
• In fattoush, the Levantine bread salad, where it is the defining flavour rather than a garnish.
• On grilled and roasted meat, especially chicken and lamb, either in the rub or scattered at the end.
• In za'atar, the herb and sesame mixture, where sumac provides the sour note — see za'atar.
• On raw onion. Sliced onion tossed with sumac and salt is a standard accompaniment to kebabs across Turkey and the Levant, and it takes the harshness off the onion while adding sourness.
• Over roasted vegetables, particularly cauliflower, aubergine, carrots and potatoes.
• On eggs, fried or poached.
• In a dressing, whisked with olive oil and a little water or lemon.
• On flatbread, with oil, before or after baking.

Buying it

The quality range is wide and the signs are visible.

Colour

Deep, dark, purplish red. Bright orange-red or brownish sumac is old, low-grade, or heavily bulked out.

Texture

Slightly moist and clumpy, because good sumac retains a little of the fruit's own oil. Bone-dry, free-flowing powder is usually old.

Ingredients

Sumac and salt. Some cheaper products add citric acid, colouring or a great deal of salt — check.

Aroma

Fruity and faintly tannic. If it smells of nothing, it will taste of nothing.

Storage

Sealed, dark, cool. It loses its colour and its sourness over a year or so.

A note on the plant

Culinary sumac is Rhus coriaria. Several North American ornamental sumacs are unrelated to what is sold as a spice, and one distinct species is toxic — which is a reason to buy the spice rather than to forage without expertise.

Sumac onions, and why they work

The single most useful thing to make with sumac, and it takes two minutes. Slice a red or white onion as thinly as you can, put it in a bowl, and toss it hard with sumac and a good pinch of salt until every slice is coated a dusty red.

Two things happen. The salt draws water out of the onion and collapses its cell structure slightly, which takes the aggressive raw edge off — the same effect as soaking sliced onion in cold water, achieved faster. And the sumac contributes acid, which does the same job from another direction while colouring the onion.

What you end up with is a sharp, sour, softened onion that works beside anything rich: grilled lamb, kebabs, roast chicken, a lentil dish, a flatbread. It is standard across Turkey and the Levant for exactly that reason. Add chopped parsley and it becomes a salad in its own right.

Common questions