An ice house in Iran - Image from Gardens of Persia, Penelope Hobhouse, photo by Jerry Harpur, published by Floriligium (yes, the same wonderful gardening bookshop in Glebe)

Four hundred or so years ago Persian engineers made ice without electricity.

Ice houses (yakhchal in Farsi, or icehouse) kept ice in the burning heat of the Iran plateau.  They’re rarely used today.

They’re up to 20 metres high and 6 or so metres below ground.  A single door is insulated with thick, dry grass.  Thick walls, 2 metres at the base, and their shape – an inverted funnel  which allows cooling wind to spiral down the exterior – keep the ice frozen for the summer.  The walls are made of sand, clay, egg white, lime, ash and goat hair. During the winter there are shallow ponds with high walls on the sunny side which are filled with water which becomes ice.  Thus, Persian wealthier classes ate ice cream several centuries ago without electricity.

Thanks to the author of this book for the text: Two wings of a nightingale – Persian soul, Islamic heart by Jill Worrall, on the road in Iran, Exiles Publishing 2011 P 68