Eli5: How did people make and keep ice in medieval times, and how do we manufacture ice cubes now ?
In: Technology
Nobody made ice until the 19th century. Best you could do was collect it and try to keep it cool in designated buildings/rooms
It wasn’t made, it was taken from things like glaciers in thick chunks before being transported. Proper ice houses were used for storage, you can still see some across northern Europe especially. They’re often like outhouse buildings, made with thick stone (I think) where it was insulated and stored.
They didnt make ice in medieval times. Places that were close enough to some where that had ice naturally got ice blocks cut out from there and transported it home or bought it from some one that brought it to town.
Today you put water in a freezer and you have ice.
For mass production there are machines that make the process repeatable but its still putting water in a freezer.
> how do we manufacture ice cubes now?
1. Fill ice cube tray with water
2. Put in freezer
3. Wait
4. Profit
Did you only grow up with refrigerators that have built-in ice makers or something?
You’ve gotten a few answers so let me fill in some gaps:
Up until modern refrigeration, ice was harvested (like in the opening scene of Frozen) and transported to wherever it was needed. Obviously moving ice is hard so to insulate it, the ice was wrapped in all sorts of things like animal fat, straw, or just more ice!
There’s a really great movie from a few years back about a thwarted political coup. The film takes place in a mountainous northern climate where ice and snow are intricately related to daily life. The intro has a great depiction of how ice was harvested, packed, and transported for sale. You should have no trouble finding it–it’s still Frozen in pop culture. Even 11 years later we just can’t Let It Go.
Did you even see the Disney movie Frozen? The character Kristoff has the job of harvesting ice, so that’s how they got it back then.
The opening scene of Frozen shows the process of harvesting ice which has been little changed since medieval times. Blocks would be cut and then transported to cities. In the 1850’s ice was harvested in Alaska, where they build sawmills for the purpose of making sawdust to insulate the ice for shipping to California.
However, going back to the medieval period, once the ice was harvested, it would be placed in stone and earth ice houses. [This giant ice house](https://en.wikipedia.org/wiki/Tugnet_Ice_House) is just down the road from me and was used for preserving salmon. Castles would have their own, smaller ice houses.
Interesting timing for this post. I had some issues with my fridge and had to do a deep defrost, as some drainage tubes were frozen.
I’m aware of how ice houses worked, basically giant igloo coolers. I got a big plastic tub, lined it with a wool blanket, then a down blanket, then a towel. Then I added all the frozen food from my freezer. I moved the tub to my bed because I knew the mattress would insulate the bottom. I then created a pillow fort around the whole tub, and finally piled my bedding on top of all of that.
4 hours later, when the fridge had purged all of the water, and I was putting things back, not only was the frozen stuff still solid, but some meats I had moved from the fridge were also frozen.
Complete success. And my fridge is working fine now.
They would wait for winter when lakes and rivers froze over. They would then bore a hole, insert saws, and cut out blocks.
The blocks would get stored in insulated shacks, caves, or underground cellars. In between blocks they may use materials like sawdust to insulate the ice and keep the cold in, reducing meltage. Ice would keep like this well into the next winter.
As for modern times, we have refrigerators that take city water and lower its temperature long enough to freeze. Usually the system has some sort of mold so the ice makes cube or chip shapes making it easier to scoop into drinks and bags.
Refrigerators themselves use a compressor to force a coolant around the appliance and it pulls in heat. The heated coolant cycles to an exhaust outside the fridge and is basically dumped into the surrounding area. It extracts the heat from inside and moves it outside.
Bear in mind the coolant doesn’t really get “hot” just warmer than it normally wants to be and then cooled outside. So the process is gradual. Once already cold the temperature is easier to maintain. More cold objects in the fridge or freezer help it resist changes in temperature.
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