The Coolgardie safe and the physics we still use
How did anyone keep food cold out here before refrigeration?
Published 09/10/2026. Written by the Pristine Cooling team, Kalgoorlie.
With a wooden box covered in a wet hessian bag, invented about forty kilometres from here. The Coolgardie safe kept food cold in a desert gold rush town that had no power and no mechanical refrigeration. It worked on the same physics running in the evaporative coolers we install today.
The problem it solved
Coolgardie in the 1890s was thousands of people in the desert chasing gold. Food had to come a long way to get there, which made it scarce and expensive. Then it sat in the heat.
There was no ice. There was no power. Whatever was going to keep a bit of meat edible until tomorrow had to be built out of what was already in the camp.
What one man noticed
A Coolgardie contractor named Arthur Patrick McCormick worked out that a damp cloth wrapped around a bottle chilled what was inside. A draught over the cloth made it colder still Museums Victoria on the Coolgardie safe. He put his finger on why. Changing a liquid into a gas takes energy, which has to come from somewhere.
It comes out of whatever the water is touching. That is the entire trick. It is the same reason a wet shirt feels cold in a breeze.
He later became Mayor of Narrogin.
How the safe worked
The build was simple enough that anyone could copy it, which is exactly what happened.
A galvanised tray sat on top, full of water. A hessian bag hung down over the sides of the box with one end sitting in that tray. The hessian pulled water up out of the tray by capillary action, so the whole bag stayed damp. When a breeze blew through the wet bag the water evaporated. The energy that took came out of the air and the food inside. A second tray underneath caught the drips the Coolgardie safe, how it was built and how it worked.
The tray on top got filled twice a day. Some versions hung strips of flannel from it to drip water down the bag and keep it wet between fills Museums Victoria on the Coolgardie safe.
They lived on verandas, because the thing needed moving air to work at all.
The part that makes it a Goldfields story
A cooler that runs on evaporation needs a steady supply of water. Coolgardie did not have one.
What the goldfields did instead was condense it. Salt water went through condensers to produce fresh. By 1898 there were six companies in the business of supplying condensed water Museums Victoria on water supply in the goldfields.
So the first refrigeration out here ran on water that had itself been manufactured, in a town that had neither. That is a fairly Goldfields way to solve a problem.
Did it actually work
It did. Tests have put the inside of a Coolgardie safe somewhere between 3 and 9 degrees below the outside air at midday, depending on how much breeze it was getting measured performance of a Coolgardie safe.
That is not a fridge. It was never going to be. But the difference between 42 degrees and 34 degrees is the difference between meat that lasts the afternoon and meat that does not.
The same physics is still in the shed
A modern evaporative cooler is the same idea with the manual labour taken out.
The hessian bag became a wetted pad. The tray somebody filled twice a day became a pump circulating water over that pad. The veranda breeze became a fan pulling air through it. What happens inside the wet material has not changed at all. Water evaporates, that takes energy, the air passing through comes out cooler than it went in.
There is more on where evaporative sits against the other options in the types of air conditioning.
Why it was invented here rather than somewhere else
Evaporative cooling only works when the air is dry enough to take on more moisture. Humid air is already carrying what it can hold, so the water on the pad has nowhere to go and the whole thing stops cooling.
Goldfields air is dry and it moves. That is the ideal case, which is why the technology was worked out in this part of the country rather than on the coast. It is also why evaporative is still worth specifying here when it would be a poor choice somewhere humid.
A hundred and thirty years on, the same conditions that made a wet bag work in Coolgardie are the reason evaporative coolers still get installed across the Goldfields today.
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