Coolgardie safe
Evaporative cooling food safe from the Australian gold rush.
The Coolgardie safe is a simple food storage device that uses evaporative cooling to keep perishables fresh longer. It works on the principle that water absorbs heat as it evaporates. The invention is named after the Western Australian mining town where it was created, Coolgardie, located near Kalgoorlie-Boulder.
During the early 1890s, Coolgardie experienced a gold rush, which was followed by the one at Kalgoorlie-Boulder. Prospectors arriving to seek their fortunes faced the problem of keeping food from spoiling, leading to the development of the Coolgardie safe. It was invented in the late 1890s by Arthur Patrick McCormick. He adapted the same method used by outback explorers and travelers to cool canvas water bags: when wet, the canvas fibers swell and hold water, some of which seeps out and evaporates. This process works best when air moves past it, such as in a moving vehicle or a breeze. Explorer and scientist Thomas Mitchell is often credited with adopting this technique after observing some Indigenous Australians using kangaroo skins to carry water.
The safe was built from wire mesh, hessian, and a wooden frame, with a hot dip galvanised iron tray on top. This tray was filled with water, and a hessian bag hung over the side with one end in the tray to soak up water. Through capillary action, the hessian acted as a wick, drawing water from the tray. When a breeze passed through the wet bag, the water evaporated, cooling the air inside the safe and the food stored there. This cooling occurs because the water needs energy to change from liquid to vapor, drawing that energy from the metal mesh interior. A metal tray underneath caught excess water. Modern tests have shown that, depending on the breeze, the inside of the safe could be 3–9 °C cooler than the outside air during midday.
The safe was typically placed on a veranda where a breeze could reach it. It was a common household item in Australia until the mid-20th century. Safes could be bought ready-made or easily built at home, and some metal panel versions were highly decorated.
- inventor
- Arthur Patrick McCormick
- year_invented
- late 1890s
- place_of_origin
- Coolgardie, Western Australia
- field
- Food preservation / evaporative cooling
- known_for
- Low-tech evaporative food storage safe
Lore & Background
The Coolgardie safe was invented by Arthur Patrick McCormick in the late 1890s in Coolgardie, Western Australia, a town that experienced a gold rush in the early 1890s. Prospectors needed to extend the life of their perishable foods, leading to this invention. McCormick applied the same principle used by explorers and travellers in the Outback to cool canvas water bags: when wet, the fibres expand and hold water; some water seeps out and evaporates, cooling the contents. This technology is commonly thought to have been adopted by explorer and scientist Thomas Mitchell, who observed how some Indigenous Australians used kangaroo skins to carry water.
Reader's Guide
The Coolgardie safe represents a significant low-tech solution to food preservation in hot, arid climates before widespread refrigeration. Its design—a wooden frame with wire mesh and hessian, a galvanised iron water tray on top, and a drip tray below—used capillary action to draw water through the hessian, which then evaporated when a breeze passed through, cooling the interior. Modern tests show interior temperatures 3–9 °C cooler than the atmospheric temperature during midday, depending on breeze. The safe was usually placed on a veranda for airflow and could be purchased ready-made or easily constructed at home. Some metal panel safes were highly decorated. Its legacy lies in demonstrating how basic physical principles—latent heat and heat of evaporation—can be harnessed for practical food storage, and it remained common in Australian households until the mid-twentieth century.
Did You Know?
- The Coolgardie safe was named after the mining town of Coolgardie, Western Australia, where it was invented.
- It uses the same evaporative cooling principle as canvas water bags used by Outback explorers.
- The safe's hessian bag draws water from a tray by capillary action.
- Modern tests show the interior can be 3–9 °C cooler than the outside air during midday.
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