Sumac - Ground Red Sumac, No Salt or Citric Acid

Sumac is the dried and ground fruit of a Mediterranean shrub, and it is one of the few spices whose whole purpose is sourness. It tastes tart and fruity with a light astringency - people reach for lemon as the comparison, and it is close enough to be useful, but sumac is rounder, less floral and more like a dried red berry than like citrus.

Its great practical virtue is that it is a dry acid. A squeeze of lemon brightens a dish and also waters it down; sumac brightens without adding a drop. That makes it the right tool for anything you do not want to make wet - a rub for grilled meat, a dusting over rice, a finishing scatter on hummus or on fried eggs.

It is also one of the most commonly adulterated spices on a shelf, which is why the ingredients line here says what it says. Sumac is frequently cut with salt, which bulks it out and flatters the sourness, or with citric acid, which sharpens a tired batch. This is neither: it is 100% ground sumac. If you have bought sumac before and found it tasted mostly of salt, that is what happened.

There is a texture tell worth knowing. Pure sumac is slightly moist and faintly oily to the touch, a deep brick red, and it clumps a little in the pouch. A sumac that is bone dry, free-flowing and bright uniform scarlet has usually been helped along. Break a gentle clump up with a dry spoon and think nothing of it.

The sourness comes from acids in the fruit itself - the same family of fruit acids that make apples and grapes tart - which is exactly why added citric acid is unnecessary in a good batch and why it is used to prop up a poor one.

This is not an Egyptian crop and we are not going to pretend otherwise. Sumac is an Anatolian and eastern Mediterranean shrub, and ours is produced in Turkey, which is the largest commercial source. It has been the everyday souring agent of that whole region for a very long time, seasoning food there before lemons ever arrived.

Use it at the end. Long cooking dulls it, so add it off the heat or at the table: over grilled chicken, lamb or fish, through a fattoush, across a bowl of hummus, on eggs, on rice. One particular trick is worth the price of the pouch on its own - rub a spoonful into raw sliced onion and leave it a few minutes, and the onion softens from harsh to sweet and sour.

It is also the sour third of za'atar, alongside thyme and sesame, and that blend is where most people meet it first. Sumac's long standing in the traditional cooking of the Levant and Anatolia is described here as history rather than as a health claim, and it is not medical advice.