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1. Fridges are an ancient invention.

An early form of ice house was built in 400 BC. Located in the Dasht-e Lut desert in Persia, this huge conical stone structure remained cool inside despite the arid weather outside. It was called a yakhch膩l. At the bottom of a pit within this large chamber, ice covered the floor beneath a layer of straw. These early ice houses were used to store surplus crops.

Mysterious conical adobe and brick wall and structure of old ice storage in Abarkuh, Yazd, Iran.

2. Yakhch膩ls weren’t even the oldest fridges.

According to cuneiform inscription dating from 1780 BC, King Zimri-Lim built a form of ice house in the city of Terqa on the banks of the Euphrates. There were probably versions of this structure built by ordinary people – but unfortunately no one inscribed anything about that.

3. Ancient China used ice houses to make ice cream.

It was made from frozen buffalo milk, flavoured with fruits and spices. These included camphor, which tastes like mothballs. Yum.

4. Ice stores were for the rich in society.

Right up until the 17th and 18th centuries, poorer people had to find other ways to keep food cool. In the Orkney Islands, Bronze Age people dug rectangular pits into the floors of their homes and covered them with stone slabs, for example.

5. The modern fridge had many inventors.

In Australia, a Scotsman called James Harrison was the first to build an ice making machine. He even patented one in 1860, but he didn’t find commercial success. He built on the work of inventors such as Scottish Professor Thomas Cullen, who used rapidly evaporating liquid to build a small refrigerating machine in 1758. Michael Faraday also invented his own system of refrigeration in 1821. But the innovation that truly caught on came in 1856, when Ferdinand Carré used rapidly expanding ammonia to create a chill. The basic principle is still widely used today. In 1876, Carl von Linde patented a new system of liquefying gas, which led to the development of a reliable ammonia refrigerator.

6. The fridge became a household name in the 20th century.

As the supply of electricity spread, so did electric refrigerators. These work by causing the coolant circulating inside them to turn from a liquid into a gas. In the 1920s, engineers replaced ammonia with synthetic coolants like freon – a chlorofluorocarbon or CFC, which we now know damages the ozone layer. Since then, new coolants have been developed that don’t include CFCs – although they are still greenhouse gases.

7. Over 98% of homes in the UK have a fridge or freezer today.

And 99.8% of homes in the US. Now that food can now be stored and shipped more safely, this humble appliance has significantly changed the way we eat, shop and live.

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