Eli5: How did people make and keep ice in medieval times, and how do we manufacture ice cubes now ?
In: Technology
No one here has mentioned that you could *make ice in the desert* as far back as 400BCE.
Humanity was *making ice* looooong before the 1900s, and long before medieval times.
https://en.m.wikipedia.org/wiki/Yakhch%C4%81l
My grandfather had this as a job in Michigan US. In the 1930s. They cut the ice from the lake and transported it for the ice boxes. Marvel to me using this phone as a computer to respond while that was his life. He’s been gone many years but legacy lives on.
In the Jura mountains I know they had two way
There was caves which maintained ice, all year, and produced more ice during winter.
They dug holes, buried in it the ice, and used straw as isolant.
Maybe they had more.
They didn’t. They cut it from frozen lakes in the winter with big saws and then packed it in underground ice houses packed with sawdust. Warmer climates did not have access to ice.
“Manufacture” is a generous. Ice was harvested.
In desert regions, the nights get bone cold when the air is dry. You want ice? Leave a thin layer of water out over night, and collect before sunrise.
In regions with a winter, or atop large mountains, you’d harvest ice from frozen lakes. That opening scene from the movie Frozen? Accurate depiction of the ice trade.
After ice was harvested, people could store it in various types of ‘ice houses’. They’re basically buildings made out of an insulating material to keep the inside cold. They could get very advanced too.
Persian Yakhchals for instance were basically giant trench freezers. Walls were 2 meters of water proof mortar. It’s a massive pit in the ground with a massive spiralling roof designed to suck up hot air, and multiple vent holes abusing physics to suck in cooled air.
In the book Farmer Boy by Laura Ingalls Wilder, they cut it from rivers and stored it in buildings insulated with sawdust.
Now a days it’s mostly just large refrigeration units that are just upscaled version of your home freezer.
Persians developed yahkchal around 400 bc that used evaporative and radiative cooling and a bunch of insulation to create essentially a refrigerated warehouse that could store ice pretty much year round, some were even used to produce ice. They required a fairly specific climate to function namely a dry desert with cold nights and a steady supply of cool water, typically supplied by aqueducts. Some of them used large shallow outdoor pools to freeze water in the cooler months and stored it inside as blocks through the warmer ones. Lot of these were still in regular use right up until electricity and modern refrigeration became commonplace.
For storage, a lot of people have mentioned insulation which is huge for ice houses, another addition to these was to make them deep in the ground, if you had earth you could dig into the temp at anything 10 feet or below (maybe even less) stays around 55 degrees no matter what is happening on the surface so you already had an advantage of not having to insulate against really hot temps as long as you could build your ice house a bit deeper.
If you can find it, the show “how we got to now” did a good episode of history of refrigeration and stuff
There’s an ice house on my old university campus- basically looks like a hobbithouse designed by an S&M fiend. They had an artificial lake that they could drain to be only a few inches deep so it’d freeze easily in the british winter then stored it underground, a good winter could last all year without importing any.
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