Making Sea Water Drinkable: Desalination With and Without Fire

You can make seawater drinkable relatively easily if normal water is not available. In this article we will show you two methods for desalinating seawater – with and without fire.

Making sea water drinkable with fire

Instead of vacation, do a survival training near the sea, learn how to use fire to make the salt water drinkable.

• You will need a larger and a smaller vessel, such as a drinking glass, a piece of plastic wrap, and a fire source, such as a campfire.
• Place the small vessel in the middle of the larger one and fill the larger vessel with seawater. There should only be so much more water in the large vessel that there is sufficient distance to the edge of the smaller vessel.
• Place the foil over the larger jar and secure. It’s even better if you have a lid for the large jar. Then put it upside down.
• If you use foil, weigh it down in the middle of the smaller container, for example with a small stone. A trough should form where the condensed water will later collect.
• Now heat the seawater over the fire source. However, keep a sufficient distance between the fire and the vessel with the sea water.
• The water should only heat up very slowly. When it begins to steam, the water vapor will condense on the inverted lid or the trough of the foil. From here, the condensed and therefore salt-free water drips into the small vessel in the pot.
• Be careful not to boil the seawater to the point where bubbles form. As a result, it could slosh into the smaller vessel – and again salt the drinking water obtained.
• The condensed water that collects in the smaller container is free of salt and therefore safe to drink.

Making sea water drinkable without fire

If you don’t have a fire source available, you can harness the power of the sun to desalinate seawater.

• The principle is the same as desalinating seawater using fire. You just have to be a lot more patient.
• The structure is the same: you need a larger vessel in which you place a smaller one. You’ll also need something to cover the larger vessel.
• With this method, foil works much better than a lid. The foil allows the seawater to heat up and condense better if you use the sun as a heat source.
• So place the small container in the middle of the large one, place a foil over it and weigh it down in the middle so that a hollow is formed.
• Put the whole thing in the sun. Sea water warms up and condenses. The condensed water drips from the trough of the foil into the smaller container.
• By the way: In a real survival emergency, you hardly have cling film or anything similar to hand. You can use any type of foil to extract drinking water from seawater, including your rain poncho.

Why desalinate seawater at all

Even if you are very thirsty, you should not drink sea water.

• The reason for this isn’t that seawater doesn’t taste good due to its high salt content.
• When you drink seawater, a chemical process called osmosis takes place. Roughly speaking, osmosis is about the fact that liquids always seek a balance in terms of the concentration of certain substances.
• The salinity of seawater is higher than the salinity in body cells.
• In order to compensate, the salt water draws fluid from the body cells – and since sea water has a very high salt concentration, a lot of fluid is drawn from the body cells.
• In principle, if you drink a lot of salt water, you will die of thirst internally.
• Therefore, knowing how to desalinate seawater and thus make it drinkable is definitely helpful when planning an adventure vacation.