This method is used by gardeners in the village of Dulab in the western Iranian Province of Kordestan.
To produce raisins, gardeners boil wood ash in water, let the water cool down and the ash to settle down. The result is what they call “Khoushab”.
The gardeners then soak the grapes with Khoushab and let them dry on rooftops, under the sun. It takes almost 15 days for the grapes to dry.
The Boulav tradition has its roots in the past and has turned Dulab into a raisin hub in the region. Dulab is a terraced mountainous village, which is located 40 kilometers away from the Kordestan capital of Sanandaj.