Couple of weeks ago I came across these sumac berries in the local farmers market in Erdek Turkey. After contemplating and asking around what I can do with them I bought some the following week.
Apperantly locals here soak them in water for a short time like 10 minutes and use the water in dishes like stuffed peppers instead of lemon juice. I kept a few branches to do exactly that when I go back to London.
I have found online that I can get sumac spice from these berries using a food processoor and a course sieve. That's what I did with the rest of the berries.
They were already dried so I did not need to dry them at home. I separated the thick wooden parts and stems as best as I can and let the food processor do the rest of the work on the highest setting for a few minutes.
Then I sifted the processes berries through a rice washer strainer which was the most coarse strainer I got at hand. Result is lovely homemade sumac that I will carry to London and hope that it will last a long time.