This pungent Middle Eastern spice is the berry of a type of rhus tree, of which there are over 150 varieties, including poison ivy. The tree that produces sumac berries is known as Rhus coriaria, but as many rhus trees are highly toxic, I would advise caution on the off chance that you were to stumble across one.
Sumac is native to the Mediterranean and is related to the mango tree. It grows to a height of 3 metres (8 feet), with dense dark green foliage. The spice itself comes from the red berries that festively adorn the tree in clusters around 10 cm long. The berries will transform from a pinkish colour when immature to a deep red when ready for harvesting.
When packaged for sale in a spice shop, sumac will almost always be powdered, its colour a glorious burgundy. The flavour is a hedonistic melange of sweetness, peppery pungency and acidity. Indeed in Roman times, when lemons were unknown in most of Europe, sumac was an important souring agent.
Once the berries are ripe, they are harvested and dried in the sun for 2 - 3 days. They are then ground in special stone mill that separates the aggressively acidic husk from the berry. At this stage salt and oil is often added to sumac as a preservative and colour enhancer.
Sumac has numerous uses in the kitchen. Lamb, chicken or fish that has been rubbed with the spice and some garlic oil is delicious when grilled. It provides a tantalizing depth to a Middle Eastern salad containing tomato, onion and avocado and if you sprinkle a little onto homemade flatbread before cooking, your pre-dinner snack will be lifted towards gastronomic heaven.