Sumac: Sour Without Acid Heat

Sumac has been used as a souring agent in the Levant and Middle East since antiquity — it predates the introduction of lemons to the region (lemons arrived from the Far East in the 10th century CE). The Romans used Roman sumac (a related species) for its sourness before citrus became available. In the Palestinian culinary tradition, sumac is both a seasoning and a cultural marker — its use distinguishes Palestinian cooking from neighbouring traditions that use different souring agents.

Sumac (Rhus coriaria) — the dried, ground berry of the sumac shrub — provides a fruity, wine-red sourness that is qualitatively different from any other souring agent in the Levantine tradition. Where lemon juice provides a sharp, immediate citric sourness and vinegar provides a harsh acetic bite, sumac's dominant acids (malic acid, tartaric acid) produce a gentler, rounder sourness with a fruity depth and the faintest astringency from the tannins in the berry. It is the souring agent of Palestinian, Lebanese, Syrian, and Turkish cooking.

• Dried cranberry or dried barberry in Persian cooking (zereshk) provides a comparable fruity-sour element
• Amchur (dried green mango powder) in Indian cooking provides malic acid sourness in the same structural role
• Tamarind's tartaric acid is in the same acid family as sumac's malic acid — both gentler and rounder than citric acid

Sumac is the Levantine culinary tradition's primary souring agent and as such plays the same structural role as lime in SE Asian cooking, tamarind in Indian cooking, and lemon in Mediterranean cooking. As Segnit would note, the malic acid in sumac is the same acid that gives apples their characteristic tartness — which explains why sumac and stone fruit are natural companions in Palestinian cooking (the acid registers are related), while sumac and fatty lamb is a pairing of contrast: the tannins from the sumac berries cut the fat perception while the malic acid brightens the meat's savoury depth.