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The title basically says what I need to ask, but I have been wondering this. I currently just say a wizard comes in and cools down the drinks, but I have started to grow out of Magic and Sorcery and more into realism. Say the city is in roughly 1100-1300 AD and placed somewhat near a desert. How would a city realistically get somewhat cold drinks?

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    $\begingroup$ Having seen you have accepted an answer just after 1 minute, you might want to wait some more. In 24 hours you might get more/better answers from users all around the world, and a question with an accepted answer may quench the answer effort. $\endgroup$ – L.Dutch Sep 25 '17 at 6:02
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    $\begingroup$ Adding to @L.Dutch's comment above, you may want to see also Please wait at least 24 hours before Accepting an answer on Worldbuilding Meta, which discusses this in some more depth. $\endgroup$ – a CVn Sep 25 '17 at 6:38
  • $\begingroup$ I have seen this in movie Kingdom of Heaven and here is related answer on Movies StackOverflow $\endgroup$ – Rahul Sep 25 '17 at 10:36
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    $\begingroup$ Define COLD - because with all respect, underground is quite cold. Unless you want frozen - most wells are quite cold. $\endgroup$ – TomTom Sep 25 '17 at 17:44
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    $\begingroup$ You probably seen the animated movie "Frozen". In the opening scene, what those people are actually doing, and why? $\endgroup$ – Alexander Sep 25 '17 at 18:50

18 Answers 18

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Sal ammoniac and water

Sal ammoniac (ammonium chloride, NH4Cl) can be mixed with water, 5 parts to 16 parts water, to form a frigorific mixture at −15°C / 4°F. This is more than cold enough to form ice.

Sal ammoniac is a rare crystal that is found "as encrustations formed by sublimation around volcanic vents[,] volcanic fumaroles, guano deposits and burning coal seams". Sal ammoniac was known to the Roman empire, hence well before the medieval ages.

enter image description here

Sal ammoniac, image by Robn Lavinsky, CC-BY-SA 3.0, source

It would be a very exclusive thing, but none-the-less possible with mundane means when deposits of sal ammoniac are available.

This would probably be combined with measures mentioned in other answers — evaporation clay pots and root cellars — to get the water somewhat cooled to begin with, which makes the ice last longer. Also if we are talking hot desert, people would probably bring out water during the night to let it cool (hot deserts can be quite chilly during the night) and then bring it inside in the morning before the sun warms everything again.


However(!)... reality check, part 1

You asked for more realism so...

Be aware that this is not a thing that medieval desert people would do, at least not for the purposes of keeping yourself cool. Drinking something cold on a hot day does not actually cool you. It feels nice, but for all practical intents and purposes you do not get any colder, and so the chilling is a wasted effort. The notion to drink something cool on a hot day is a modern thing that only came about with the invention of refrigeration in the early 1900s, and we suddenly had the luxury of having some excess cold.

In fact, it may even be more advisable to drink something hot in order to cool off. This is because if you can fool the body to think that it is overheating, the body will take steps to cool itself, the most salient such step being to open up the superficial blood vessels to dump more body heat to the skin and from there to the surrounding air.

Hence serving a cool drink in a hot desert medieval town would be more of a novelty thing; a sort of bragging where your hosts show off that they can do something very peculiar and nigh magical, namely create cold.

So if you wanted to use this to actually keep cold, you would chill water, soak a rag in it, and press this rag against an area of the body where you have a lot of superficial blood vessels — like the hands, wrists and head. This will create actual relief from heat that is much more effective than drinking, since that rag will quickly soak heat from your skin, cool the blood in the skin, and that cooler blood will then be transported back to the core of your body.


However(!!)... reality check, part 2

Also note the following:

  • Drinking something ice cold when your body is subjected to a lot of heat is actually dangerous.

  • Do not — under any circumstance — give a person that seems to be overheating cold water to drink.

Drinking something ice cold when you are warm can cause a very rapid drop in blood pressure in your head. You essentially create a temporary circulatory shock. The result is that you can faint on the spot without any warning, by simply drinking something very cold.

This happened just a couple days ago to an acquaintance of mine. We were out by the hotel pool on the Mediterranean, sunbathing and sweltering in the heat. A waiter brought drinks that were like slushies: 50% crushed ice, 50% liquid. My buddy took a big swig of his drink, said "Ooooh, dat brain freeze", and then — just like that — he keeled over, fell out of the beach chair, and hit his head on the ground earning him a black eye.

Again: the proper way to cool off if you are overheating is not to drink cold liquid but to use a cold rag on the head, wrists and hands.

So your hosts in this hot desert town would most likely tell their esteemed guests "Drink slowly and very carefully", because it does not leave a good impression to have their guests faint from being offered a drink. :)

Then again: that would make for some light comedy.

— What... why am I on the floor?!

— My dear friend, the rich merchant chuckled, that sometimes happens. I suppose I should have warned you.

— Oh... is it...

— No, no, not at all. It fades really quickly. Just sit up slowly on that chair over there.

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    $\begingroup$ I like your howevers. In fact, there is a good reason why people in actual deserts prefer HOT beverages, because it creates a perceptual cooling for the rest of the bodies. $\endgroup$ – Weckar E. Sep 25 '17 at 13:03
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    $\begingroup$ @WeckarE. Exactly... in fact I think that is is not just perceptual cooling but actual cooling. This is because if you can fool the body that you are even hotter than you already are, the body will expand the superficial blood vessels, which in turn will transport heat from the core of your body to the skin, which will cause an increase in the amount of heat that is being radiated away from your body. $\endgroup$ – MichaelK Sep 25 '17 at 13:42
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    $\begingroup$ Good answer. No coincidence that in the Middle East Coffee and hot tea are the most common beverages, even during the heat of the day. Also: everyone seems super addicted to sugar and nicotine, which may not have anything to do with cooling, but might just give a nice rush. $\endgroup$ – JBiggs Sep 25 '17 at 15:54
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    $\begingroup$ "More of a novelty thing" makes me thing of A Hundred Years of Solitude, a magical-realistic novel in which people paid money at the circus to see ice. It was at least as amazing as the flying carpet which the circus brought on a different occasion. $\endgroup$ – Peter Taylor Sep 26 '17 at 19:55
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    $\begingroup$ I'm a little dubious on this often repeated statement that drinking cold things doesn't cool you off. Mainly because of laws of thermodynamics. When you feel hot, it's because your body is struggling to remove excess heat. When you put cold liquid inside of you, it will immediately start to warm up. Not because your body is working to heat it up but because it's already warmer than the cold liquid. This cold liquid must absorb some amount of heat from your body that would otherwise need to be removed mainly through sweating. $\endgroup$ – JimmyJames Sep 27 '17 at 16:30
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Get snow from the mountains and/or in the winter. Pack a great heap of it in insulating material like sawdust in a deep basement. Sell small amounts during the summer.

  • Difficult in a hot desert without ice/snow source (not all deserts are hot).
  • Extremely expensive.

Store the drink bottle in wet sand in a porous clay container. Evaporation will help keep the drink slightly cooler than the outside temperature.

  • Affordable.
  • Not very effective.
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    $\begingroup$ Regarding the storing of ice, this was actually done. And caused protests from the ice workers unions when electrical freezers was introduced in the early 1900eds. $\endgroup$ – lijat Sep 25 '17 at 5:49
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    $\begingroup$ See the Wikipedia-Article about pot-in-pot cooling: Given a constant flow of cool dry air the inner pot can achieve temperatures as low as 4.5 °C (40 °F) I would call that very effective - an excellent temperature to serve drinks at! $\endgroup$ – Falco Sep 25 '17 at 8:39
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    $\begingroup$ Ice storage was very common in the UK. Underground basements were used, they filled them with ice during winter then had a steady supply of cold during summer. This city could be near a mountain and harvest blocks of ice from the top of the mountain or a glacier. $\endgroup$ – Tim B Sep 25 '17 at 11:08
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    $\begingroup$ @Falco It depends on the Wet-bulb temperature. It doesn't work that well in hot regions with high humidity. E.g. DesertWeather.com has a chart for the Coachella Valley in Carlifornia (found that one easily). It shows an average of 22 °C in July. $\endgroup$ – Christoph Sep 25 '17 at 11:55
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    $\begingroup$ en.wikipedia.org/wiki/Ice_house_(building) $\endgroup$ – AllInOne Sep 25 '17 at 16:47
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They would build a root cellar and use it to store the beverages.

A properly built root cellar will maintain a temperature above ambient (and above freezing) in the winter, and well below ambient in the summer.

Root cellars are rather simple constructions, easily achievable with medieval technology. In fact, they were a common solution to the problem of keeping crops and other goods at a reasonably stable, above-freezing temperature year-round until refrigerators (initially iceboxes, later electrical refrigerators similar to those of today) became commonplace, and in places are still used for their original purpose even today.

This has the advantage that it doesn't depend on availability of ice (which, since you say this is in a desert region, could be a problem either because of temperature or because of lack of precipitation, depending on whether they are in a hot or cold desert), but it does require some land that can be devoted to construction of the cellar. In the scenario you describe, that shouldn't be a major showstopper; most medieval "cities" would be more like what we'd call villages today.

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    $\begingroup$ This was my first thought as well. If you go deep enough - and "enough" depends on your location's latitude, enough for a couple feet of dirt above you in some areas, enough for at least 6 feet of dirt above you in my colder area, so 10 feet deep is good - then you should be able to keep a constant temperature in the 50's or 60's, less if you combine this method with other methods. $\endgroup$ – Loduwijk Sep 25 '17 at 13:03
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In 400BCE, Persia had special structures that collected water in the winter, turned it into ice, and kept it cold for the entire summer:

See: http://en.wikipedia.org/wiki/Yakhchāl And: http://www.ccsenet.org/journal/index.php/ach/article/view/13822/12244

Yakhchāl (Persian: یخچال‎‎ "ice pit"; yakh meaning "ice" and chāl meaning "pit") is an ancient type of evaporative cooler. Above ground, the structure had a domed shape, but had a subterranean storage space; it was often used to store ice, but sometimes was used to store food as well. The subterranean space coupled with the thick heat-resistant construction material insulated the storage space year round. These structures were mainly built and used in Persia. Many that were built hundreds of years ago remain standing.

By 400 BCE, Persian engineers had mastered the technique of using yakhchāls to create ice in the winter and store it in the summer in the desert. In most yakhchāls, the ice is created by itself during the cold seasons of the year; the water is channeled from the qanat (Iranian aqueduct) to the yakhchāl and it freezes upon resting inside the structure.

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  • $\begingroup$ I've seen the natural form of this. $\endgroup$ – Joshua Sep 29 '17 at 15:22
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By using a two-pot clay cooler. (expanding on what L.Dutch mentioned in their answer)

The basic premise is that when water evaporates, the medium that it leaves is cooled down.

To quote the Wikipedia article:

A pot-in-pot refrigerator, clay pot cooler1 or zeer (Arabic: زير‎‎) is an evaporative cooling refrigeration device which does not use electricity. It uses a porous outer earthenware pot, lined with wet sand, contains an inner pot (which can be glazed to prevent penetration by the liquid) within which the food is placed - the evaporation of the outer liquid draws heat from the inner pot. The device can be used to cool any substance. This simple technology requires only a flow of relatively dry air and a source of water.

Using this technique you can get your drinks pretty damn cold, ~5°C even, although this reference is from a cooler built using modern materials and not medieval ones!

I don't have a full reference, but Wikipedia mentions this type of cooling was used in Ancient Egypt, so it would stand to reason that this sort of knowledge would be prevalent by 1100-1300 AD. Evaporative cooling techniques such as this are most effective in dry climates such as a desert or mediterranean climate. In a climate with high humidity, not so much, since the amount of cooling achieved depends on the rate of evaporation.

EDIT: thanks to Falco for advice on what to include in my answer :)

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    $\begingroup$ You should add the amazing effectiveness (since many people may believe this technique will only provide little effect) - from the article: Given a constant flow of cool dry air the inner pot can achieve temperatures as low as 4.5 °C (40 °F) - a cool coke at 5° is no problem with this pot... $\endgroup$ – Falco Sep 25 '17 at 8:37
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    $\begingroup$ You could use ether or alcohol to get an ever better effect : it would be possible to produce ice cream in the desert! $\endgroup$ – Eric Duminil Sep 25 '17 at 9:42
  • $\begingroup$ @EricDuminil Great idea - vodka cooled ice-cream, who knew? I actually want to try this now! $\endgroup$ – Korthalion Sep 25 '17 at 10:39
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They would do what we did on Earth before electric refrigeration. Harvest big blocks of ice in winter and store them in insulated ice houses for the summer. If your city doesn’t have a cold winter, they’ll have to ship the ice in from somewhere that does, in insulated wagons that travel at night.

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They have various options:

  • harvest snow during winter from nearby mountains and store it in underground rooms insulated with straw (it was done in my home region in the hearth of Mediterranean sea). Add salt for further cooling.
  • dip them into wells, rivers or sea water (again, this was a trick used by farmers to have cold wine and fruits when working in July under the scorching sun)
  • collect water from underground (either from wells or collecting rain water in underground rooms. Having had the chance to try that water I can assure you it is deliciously fresh)
  • use clay containers: clay is porous, and water permeating through the walls of the container ends up evaporating and thus cooling the container itself.
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If there's a river nearby, they could simply submerge the drinks in the cool water, and pull them out when they want to drink them. It might not be as cold as getting blocks of ice, or snow, but it might be a better if it doesn't get cold enough to get ice, or if it is too far to import it.

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  • $\begingroup$ Agreed. Fast flowing mountain rivers (or melt water rivers) can be quite cold, even during the summer. $\endgroup$ – Michael Sep 25 '17 at 8:01
  • $\begingroup$ This was my second thought (after digging below the front line), and I was looking to see if it was already here. Not as cold as ice, yes, but still plenty cold in many areas. Where I live, even when it gets quite hot during the summer the water is still cold enough that it feels freezing if you just jump in. A container of water kept submerged in naturally cold water would be plenty cold to satisfy most people. $\endgroup$ – Loduwijk Sep 25 '17 at 13:09
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    $\begingroup$ How consistent is this with being next to a desert? $\endgroup$ – Mad Physicist Sep 25 '17 at 18:27
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    $\begingroup$ @MadPhysicist I can tell you from experience that a river through a desert isn't necessarily going to be cold. The Escalante river in southern Utah is about 85 degrees F in the summer. Not incredibly refreshing, though cooler than the 100+ degrees outside. $\endgroup$ – BlackThorn Sep 25 '17 at 21:05
  • $\begingroup$ @TBear I think that as long as it's cooler than the outside temperature, it would seem cool in comparison. A city that can't get snow or ice might not even know that there is a way to make drinks colder. $\endgroup$ – Ant Sep 27 '17 at 15:59
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The Sahara gets sub-zero temperatures at night during the winter

So water should be able to freeze if present in the open in the winter and could then be carried into a deep cellar before dawn. Repeat throughout the winter and then store with sufficient insulation and you have ice in the summer.

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That's how a fridge is created for a scouts camp:

Dig a hole in a shady location outside and put the stuff to refrigerate into it. After that you will pin a tarp over the hole and keep it wet by pouring a little water over it. Through the continuous evaporation, it gets actually really cold inside the hole, even during summer. Out of my own experience I can say that it is definitively effective enough to cool down drinks, especially for a medieval setting. Instead of a tarp, you can just take a large skin. This might be even more effective as it has a bigger surface.

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  • $\begingroup$ Silly question, but do you pour the water on the tarp, or in the hole below the tarp? $\endgroup$ – Sidney Sep 25 '17 at 14:44
  • $\begingroup$ You pour it on the tarp. The tarp always needs to have some water on it (Only a small puddle, no need for a "water sack"). Your refrigerator hole itself will stay dry. $\endgroup$ – Herr Derb Sep 25 '17 at 14:50
  • $\begingroup$ I can picture this idea being discovered by medieval people, but I'm not sure anyone actually did so (?). It's not obvious how and why it would work if you're 500 years away from discovering thermodynamics. (In fact, if you had that knowledge, you could build an actual fridge with medieval technology; e.g. bit.ly/2bZGRfW ) $\endgroup$ – bobtato Sep 26 '17 at 22:50
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    $\begingroup$ @bobtato Well, why did our ancestors use fire then? I'm pretty sure they had no idea why or how it works. It just did, and it was useful. Also it's most likely that someone has built a similar construction and figured out, that after rain, it was always very cold inside. the link you have posted contains complex mechanics, which depend on thermodynamic knowledge, as such a machine is not beeing constructed on coincident. $\endgroup$ – Herr Derb Sep 28 '17 at 16:02
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In desert climates people build houses with covered (underground) trenches that travel away from the home a ways and then open to the air. Ventilation at the roof of the home draws air through the trenches where it is cooled by the earth - keeping the home cool.

Large versions of this style of dwelling will produce thick sheets of ice when water is left in these trenches overnight as convection draws the cold night air through the trenches. Example: http://www.amusingplanet.com/2013/01/ancient-ice-houses-of-iran.html

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    $\begingroup$ The OP doesn't ask how to cool a house (which is what you answer). $\endgroup$ – L.Dutch Sep 25 '17 at 7:17
  • $\begingroup$ Hi, GregM, welcome to Worldbuilding, please expand your answer to make the obvious point if you can form ice in the underground trenches this can cool drinks. This will improve your answer. $\endgroup$ – a4android Sep 25 '17 at 8:54
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    $\begingroup$ @L.Dutch If this ventilation system can form ice in its trenches, surely that can be used to cool drinks or am I missing something obvious? $\endgroup$ – a4android Sep 25 '17 at 8:56
  • $\begingroup$ @a4android, it can't form ice but it can keep the building at a low enough temperature to maintain ice in the medium to long term $\endgroup$ – Separatrix Sep 25 '17 at 8:58
  • $\begingroup$ @Separatrix For their houses, certainly, but the Iranians were able to make ice. While their houses may not have been able to make ice by themselves, ice should have been obtained from the ice houses. As I said, the answer can be improved -- by explaining this. $\endgroup$ – a4android Sep 25 '17 at 9:06
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Their is an evaporation method.Take a large pot, put a smaller pot inside(same height though), fill that gap with sand, put whatever you want cooled inside the small pot, put a large, wet cloth over it all and put it in the sun

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There was actually a trade in ice as late as the 19th century. For example, people in New England would cut ice out of ponds, put it in ships, and send it to the southern states. That trade even existed in North Africa, with ice being shipped by riders on relays of fast horses or camels from the Atlas Mountains to desert cities. It was a luxury item.

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Put it in the creek or the well. I guess a desert has a well. That's what we did when I was a kid. Should work here too.

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As noted by most others: people didn't drink cool drinks to get cool. That became only possible when industrial refrigeration became affordable (1880-1920).

Giving a guest a cooled drink was a real luxury. Akin to serving pink champagne, that kind of a luxury. Especially in a desert environment.

Ice had to be harvested during winter in cooler climates. It had to be shipped to the nearest port. Then carefully packaged transported on presumably camels or donkeys to your oasis. The local ruler would have had a specially constructed ice cellar dug deep underground where the ice was stored until it melted away. All the old great houses in Europe have one. Perhaps a few very rich rulers in an oasis had one too.

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Don't know if you already found your answer but I'll give my input anyway. Here in Portugal we learned in history classes that the king used to eat ice cream and serve it to his guests during the 1800's, so in order to do it he would have ice and snow merchants, that would drive their carts to our only snowy mountain over about 200km away. In order to preserve most of the ice and snow, they would wrap it in heavy hay and straw bundles. Somehow it didn't completely melt.

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  • $\begingroup$ Welcome to WorldBuilding.SE! You're welcome to answer questions even if there's already an accepted answer, so don't worry about that. I'm not sure whether your example can be applied to the scenario in the question, but it's not a bad first answer. $\endgroup$ – F1Krazy Sep 29 '17 at 15:55
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Water is heaviest at 4 degrees plus celcius which is the temperature a bit down in wells or other outdoor water things. Should be cold enough to cool any water based drink.

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You can achieve this by using the zeer or pot in pot method In some parts of India and some other countries, even now people use this method.

Also another relatively less successful is to suspend the drinks tied in cloths into a well.

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  • $\begingroup$ That answer was already given several times. Please take time to read through the other answers to avoid posting duplicates. $\endgroup$ – MichaelK Oct 2 '17 at 9:20

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