2,000+ years ago, Persians enjoyed cool beverages, sorbets, and other chilled treats in the desert, even in the searing heat of summer.

How?

With this: an ancient refrigerator called a Yakhchāl ("ice pit") that helped them create and store ice year-round.

Pastaitaken

There were several types of Yakhchāl, but the best studied and most iconic was a dome perhaps 15 m high and 13 m wide that was situated atop a deep pit and was likely constructed from a waterproof and highly insulating mixture of sand, clay, lime, ash, egg whites, and goat hair.

Here's how it worked: On cold nights they poured water into shallow pools dug in the shade of large walls and allowed it to freeze. Then they chopped up the ice and and transported the pieces to the Yakhchāl. In some cases water was also channeled directly into the structure.

Warm air rose and escaped the dome through vents at the top, while a mix of evaporative cooling and insulation (sometimes supplemented w/ straw) kept the ice in the underground chamber cold, even in summer. Windcatchers may also have helped pull cool air in and push warm air out.

At first, ancient Persians, like many other early cultures, likely used ice to cool and preserve food and drinks, but over time they also created frozen treats by flavoring ice, as well as chilled milk and syrups, with flowers, fruit, honey and spices.

Ice cream is OLD!

Sources & Further Reading

http://jfa.arch.metu.edu.tr/archive/0258-5316/2012/cilt29/sayi_2/223-234.pdf

http://www.ccsenet.org/journal/index.php/ach/article/view/13822/12244

https://misfitsarchitecture.com/2013/02/22/its-not-rocket-science-2-yakhchal/

http://jhre.ir/article-1-1176-en.html

Image Credits

Faloodeh, Rka11111: https://en.m.wikipedia.org/wiki/File:Faloodeh1.jpg

Sherbet, Renee Comet:
https://en.wikipedia.org/wiki/Sorbet#/media/File:RaspberrySherbet.jpg

Bastani Sonatti, Ewan Munro: https://commons.wikimedia.org/wiki/Category:Saffron_ice_cream#/media/File:Gilak,_Archway,_London_(5241860049).jpg