This podcast episode discusses ancient Persian refrigerators called yakchals. The hosts explore their construction (using a unique mortar of sand, clay, egg whites, lime, goat hair, and ash), functionality (utilizing shade, convection currents, and the freezing of water in layers), and uses (storing food and making ice for desserts like Faluda). They highlight the yakchal's impressive insulation, equivalent to a 3-inch-thick concrete wall surrounded by a foot of styrofoam. The episode concludes by noting that while modern refrigeration replaced yakchals, some remain and are being preserved for their cultural and engineering significance, offering lessons in passive cooling techniques.
