The Oldest Icebox

Even 2,300 years before the invention of refrigerators, there was a significant need to store perishable items like cheese, butter, and meat. And so, in 400 BCE, the ingenious Persians devised an efficient storage solution capable of making and preserving ice even during the scorching summer of the desert. Enter the yakhchal, a voluminous structure resembling a solid conical bowl with a deep cellar that could extend up to 20 meters underground, employing a combination of architectural features and natural cooling techniques. Typically, water was directed to the yakhchal from an aqueduct in autumn, filling the cellar. As the winter set in and progressed, the water froze, producing ice that could be used throughout the following year.

Constructed with massive walls measuring no less than 2 meters in thickness, the yakhchal was made from a mixture of clay, sand, goat wool, and ash, a composition that boasted significant thermal insulation properties. The entrance to the yakhchal also served as a ventilation opening, allowing air to cool as it entered and pushing the warm air upward, which escaped through the opening at the top of the cone. Some yakhchals were equipped with a wall covering the structure from the south, the direction from which the sun's rays were most intense. They also often had badgirs, or windcatchers, that enhanced air circulation and cooling.

Workers descended the steps along the cellar wall and packed large pitchers with chunks of ice, which were then delivered to the townsfolk. The ice served various purposes, from cooling wine and water to preserving perishable goods in private ice chambers. Yakhchals were constructed and utilized in Persia—and later in other countries in the region—until the twentieth century, when they were eventually replaced by electric refrigerators.