Yakhchal - Persia's Ancient Icemakers

By Heidi Noroozy

Recently, I went shopping for a new refrigerator – a venture that quickly made my head swim. Double doors, top freezer, bottom freezer, pullout drawers, glass or wire shelves, with or without an icemaker that can deliver ice in multiple forms, from crushed to cube, in-door water dispenser, humidity sensors to prolong the life of perishables – refrigerators today can do everything except order groceries. It makes me yearn for simpler times.

Photo by Andreas Praefcke

What I’d really like is a plain old-fashioned icebox, a pretty wooden chest in my kitchen, lead-lined for insulation with a big slab of ice to keep things cold. Well, maybe I could do without lead in close proximity to my food. And I expect the interior might get a bit slushy as the ice melts. Besides, where can you find a reliable iceman these days? But at least I wouldn’t have to battle spoilage when the power goes out.

Or maybe I could just build an ancient Persian yakhchal in my back yard.

Invented around 400 B.C., a yakhchal is a kind of walk-in icebox that looks like a huge, conical beehive. In ancient times, they were built mainly near desert towns to store ice and keep food cold during the scorching summer months.

A yakhchal has two parts: one above ground and the other subterranean. The above-ground dome, which can be as high as 60 feet, is made of a special brick material called sarooj, a mixture of sand, clay, egg whites, lime, goat hair, and ash. The sarooj walls create a waterproof barrier and provide a kind of thermal insulation. Beneath the dome lies the ice pit, a deep cavern dug into the earth for storing ice.

Although “yakhchal” is the modern Farsi word for the contraption we call the fridge (and also a synonym for “glacier”), the ancient versions had a slightly different purpose. Sometimes they indeed stored food, but their main function was to make ice.

Yakhchal near Kerman, Iran

Yakhchals worked like this: a qanat, or underground irrigation trench (sort of like an upside-down aqueduct), transported water to the ice pit, where it would freeze during cold winter nights. The ice was then chopped into blocks and stored in separate chambers, where it could be easily removed as needed.

Some yakhchals operated according to a slightly different principle. Great slabs of ice would be hauled down from the mountains during the cold winter months and stored in the ice pit. As the ice slowly melted, trenches in the floor of the pit collected the runoff, where it refroze during the night and could be cut into blocks for easy transport. Pretty clever, don’t you think?

Most yakhchals had a wall built on the south side to block the searing rays of the sun and shade the ice pit. Tall towers, known as badgirs (wind catchers), were also added for ventilation. By circulating warm air from the surface and cold air from the ice pit, the badgirs acted as a kind of thermostat to better regulate the temperature inside the yakhchal.

I probably won’t build one of these practical ice houses in my small back yard. (Where would I put it?) But I am intrigued by the ingenuity of the ancients, who devised a way to meet the challenges of a harsh climate and enjoy the finer points of life: fresh food and cold drinks on hot summer days.

Water, Water...Underground

The Kavir Desert of central Iran is the last place I’d go looking for a piece of verdant paradise. But in the Fin suburb south of Kashan, on the edge of this great salt desert, lies a beautiful oasis called Bagh-e Fin (Fin Garden). Enclosed by sand-colored brick walls, the garden is a refuge of cypress-lined paths bordering blue-tiled channels that connect pavilions built over shallow pools of clear water. If you sit on a bench by one of the many bubbling fountains and breathe in the cool, jasmine-scented air, you’ll forget the heat and dust of the arid landscape beyond the enclosure.

The Fin Garden draws its water from the Cheshmeh Suleiman (Solomon’s Spring), located a short distance away. According to local lore, this spring has been the lifeblood of the local population for 7,000 years—and it has never dried up in all that time. But the most astonishing thing about this spring is not its longevity or Biblical name, but the fact that it is part of a man-made water system that dates back to antiquity. Known as a qanat, it is like a Roman aqueduct—turned upside down.

Qanats were invented by the Persians in pre-Islamic times as a way to ensure a regular water supply for settlements and agriculture in arid regions.They begin with a reservoir in the mountains for collecting snow runoff. Qanat builders, known as muqannis, dig a channel deep underground leading from the reservoir to the final destination, sometimes covering distances of many miles. Then they sink shafts at intervals to tap into the underground channel and bring the water to the surface. Some qanats make use of existing subterranean streams or a series of natural springs. In Iran, 22,000 qanats are still in operation today. Running the water underground, rather than in Roman-style aqueducts, prevents evaporation in the desert heat.

These Persian aqueducts are so difficult and time consuming to build and maintain that the Achaemenian kings of ancient Persia awarded land grants to anyone who could create one. It is astonishing how they could have been constructed at all without the use of heavy machinery, power tools, or even modern surveying equipment. Yet even in ancient times, the technology spread throughout the Middle East and as far west as Spain. In fact, the term, qanat, comes from the Arabic; the Persians called their water system a kareez.

Ab anbar (cistern) with 4 badgirs, Yazd, Iran
Photo by Michal Salaban

In some desert cities, including Kashan, the qanat is combined with a traditional ventilation system called a badgir (literally, wind trap). This is a wind tower constructed above a building and designed to capture the wind and direct it down into the interior, where the air passes over cool water flowing through the qanat. The result is a natural air-conditioning system.

The oldest qanat still in operation lies in the northeastern Iranian province of Razavi Khorasan, which shares borders with Afghanistan and Turkmenistan. This aqueduct supplies water to nearly 40,000 people in and around the city of Gonabad. It is estimated to be 2,500 years old and is being considered as a UNESCO world heritage site.

The Kashan qanat captured my imagination on a visit to the Fin Garden. Our guide explained how the water system fed the small fountains bubbling along the garden’s narrow water channels by using precisely calculated angles and the force of gravity rather than pumps.  Later, after we left the cool shade of the leafy oasis, the guide led us down a dusty lane to another walled enclosure. This turned out to be the Cheshmeh Suleiman, a pool of dark water surrounded by gray rock. I sat on a stone and gazed into the spring, which looked deep enough to emanate from the very center of the earth. How clever the ancient Persians were, I thought, to channel this unassuming pool of water through the ground and carve a life-supporting environment out of the desert.