Embora pareça inacreditável, nos tempos antigos (mesmo no deserto) eles tinham a capacidade de armazenar gelo.
Existem algumas fontes diferentes para esta informação online. Primeiramente, há este artigo escrito por alguns estudantes de arquitetura da Malásia. Sua pesquisa afirmou:
In 440 BC Iran, Iranian people had already domination the technique of storing ice in the middle of summer in the desert. The ice was brought in during the winters from nearby mountains in bulk amounts, and stored in a specially designed, passively cooled refrigerator, called an Earth refrigerator. This was a large underground space that had thick walls made out of a special mortar called sarooj, composed of sand, clay, egg whites, lime, goat hair, and ash in specific proportions, and which was resistant to heat transfer.
Isso é feito por outras fontes, como o livro de medicina Criocirurgia Cutânea , que analisam essa questão em relação à medicina antiga. Declarou:
At first glance it is not clear how ice or snow would have been available at such latitudes, but even in hot countries there were means of acquiring it. Ice could be stored, from the winter time, in ice houses where it was packed in large quantities and covered with straw or other insulating materials...Ingenuity was at its foremost when methods were developed to produce ice or slush in desert areas when extreme low temperatures at night were manipulated to freeze evaporating water. The Romans and later Iranians would dig a pit and line it with insulating straw. In it was placed a water contained and the opening was covered by a sun-reflecting shiny metal in the day but open to the elements at night. Evaporation at night led to ice forming around the edge of the container. This was collected and stored.
Por mais incomum que pareça como primeiro som, os antigos certamente tinham a habilidade e o know-how para fazer isso.