How did the Persian people manage to keep food chilled in the middle of the Iranian desert more than 2000 years ago? They used yakhchals of course!
When seen from a distance, yakhchals look more like a bee hive or a giant ant hill. However in reality, they are ancient, natural refrigerators used in Persia around 400 BC, long before electricity was invented. Situated underground, the non visible part of these large cones covers a surface area 5000 squared metres.
Yakhchals create a cold internal atmosphere by the process of evaporation. The ancient refrigerator freezes on the inside thanks to cold water carried from the mountains during winter via underground canals and qanats. In some yakhchals, mountain ice could be directly removed to be stored inside.
When summer arrived, the well conserved ice managed to keep food fresh which needed to be stored at low temperatures. This was made possible by an opening at the base of the structure which allowed cold air to enter underground where the fresh food was stored. Hot air was then evaporated thanks to a hole at the top of the conical structure.
The walls of the structure were at least two metres thick. This would have been necessary to keep everything inside isolated. These thousand year old structures were made from a skillful mix of sand, clay, egg whites, goat hair, lemon juice, ash and a water resistant mortar called sarooj. Yakhchals were build with precision so that they remained full watertight. So much so that some of these structures are still used today in Iranian villages, such as in Kerman, Meybod and even Yazd.
Thanks their skillful refrigerating system, Persians could even create an iced specialty called faloudeh. This is a delicious dessert is made from vermicelli, rice, syrup, lemon juice and rose water. (See picture below). The word yakhchal is still used in the Persian language today simply meaning refrigerator.