Sumac

Sumac is a dried, crushed fruit: coarse rather than powdery, matte and dark red. The sourness it gives is not sharp the way lemon is. It sits behind the food and works with salt. On a Syrian table it goes over fattoush, over onion salad, over grilled meat, and along the edge of a plate of hummus. It is also the red, sour part of a za’atar mix.

Where the sourness comes from

Sumac comes from the fruit of a shrub, Rhus coriaria. The ripe berries are dried, then crushed and sieved. Before lemons spread through Mediterranean cooking this was the main source of sourness; the Romans used it in vinaigrettes for the job lemon does now. Its place in the kitchen is older than lemon, and it never gave that place up.

Where it lands on the table

It is a finishing spice, scattered over the food and usually at the last moment. In fattoush it carries the sourness that sits beside the fried bread. Thinly sliced onion, rubbed with sumac, loses its bite and arrives that way next to the grill. The red line along the rim of a hummus plate is the same thing. In Aleppo za’atar the sourness comes from sumac, not from citric acid; two mixes with the same name are not always the same mix.

How to choose it at the stall

Good sumac is matte, dry and deep red. Treat anything damp, glossy or eye-catchingly bright with suspicion. The quickest test is to ask the spice merchant for a pinch and taste it: sourness should come first, and if salt arrives before it the mix has been weighted with salt. It is sold by weight, and a small amount lasts a long time.

Before the spice: the tanner’s shrub

The leaves and bark of the same plant do not go to the kitchen. They go to the tannery, because they are high in tannin, and one of the plant’s Arabic names comes straight from that trade. Different parts of it yield red, yellow, black and brown dyes. The grains on the spice merchant’s shelf come from the same plant that supplied the dyer and the tanner.