Thursday, August 5, 2004

Ice makers | New Scientist Lastword

Question

In the summer of 1809 the poet Byron and his friends visited Venice and ate ice cream in the cafes. How was ice cream made when there were no refrigerators?

BN. M. MacNaughtan , By email


Answers

>> Ice can be conserved for a long time if kept well insulated in large volumes. If you visit the famous ruins of Pompeii, you will see the remains of ice-cream stands: the inhabitants brought ice down from the slopes of Vesuvius, and presumably kept it in cellars. ...

Ice was made in the Iranian desert thousands of years ago by simply exposing a very shallow reservoir to the cold night air. At night in the desert there are no clouds to reflect back heat rising from the ground, so the temperature plummets rapidly. The reservoir cooled, and the ice that formed on its surface was collected in the morning. These reservoirs were built with a wall to shade them from the morning sunshine. ...

Robert Cailliau , Prevessin-Moens, France

>> Before refrigerators were invented, in Europe ice was brought from glaciers during winter and stored in underground "ice houses", with a north-facing entrance and very thick walls for insulation. Every large European estate had its own ice house. The ice would remain frozen through the summer months until the following winter. ...

Lynda Wallace , Ayr, UK

>> Before refrigerators, ice cream often relied on ice exported from colder climes. Canada and Norway in particular had a huge trade in ice, exporting it round the world in insulated compartments on ships.

Interestingly, when manufactured ice started to become available, many people still preferred "real" ice because the artificial stuff was the wrong colour and didn't have green bits of vegetable or algal matter in it.

Lynda Wallace , Ayr, UK

>> Ice cream was certainly being made in Italy around 1600, and was known in England a couple of decades later, when it was served at the court of King James I. ...

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