Bar of homemade soap from ash and animal fat

When you find yourself in a wilderness survival situation, cleanliness and hygiene are often not at the top of your list of priorities – but they should be. Maintaining proper hygiene in a survival situation is much more than just a mental or emotional boost. While you’re battling elements you can visually see – terrain, animals, and weather – there are unseen foes attacking you. Keeping your body clean helps you fight off, and avoid, infections and disease which can easily kill a person in a dangerous survival situation.  Soap of course, is key to that battle. As it turns out, making soap in the wild is not as difficult as you might think and utilizes materials that you would already have left over from your day-to-day survival activities (animal fat/grease and ash).

How soap works

Evidence of the use of soap-like materials dates back to around 2,800 BC in ancient Babylon indicating its potential to “clean” has been known for thousands of years. It’s even quite likely that soap was used in prehistoric times since it’s probable that at some point, cave-dwellers would have accidentally mixed ash with cooking grease creating the white-foamy substance that works well as a cleaner.

Soap’s action is fairly simple – it makes otherwise insoluble particles become soluble which allows water to rinse the particles away. In chemistry lingo, it’s an emulsifying agent capable of dispersing one liquid into another immiscible liquid. This means that while oil doesn’t naturally mix with water, soap can suspend oil/dirt in such a way that it can be removed. In simpler terms, soap causes drops of grease and dirt to be pulled off your hands and suspended in water – that’s how it gets you clean.

How ash and animal fat make soap

When fatty acids (present in animal fat or oil) are mixed with an alkali (present in wood ash), the alkali causes the fatty acid to split into fatty acids and glycerin. Through the process, the fatty acids that remain are chemically joined with potassium present in the alkali giving us “potassium salts” (potassium hydroxide) which form the basis of soap.

Making simple ash soap in the wilderness

Wood ash thrown into grease is quick and easy to make but may not be as suitable as you like for keeping your body clean (however, it certainly serves well as a cleaner for kitchen utensils, tools, etc. and does a suitably well job cleaning your body).  Here’s a method to create better homemade soap bars using common materials you’d have available in the wilderness.

  1. To begin, we need to remove potash or pearl ash (a more purified form of potash), which are forms of potassium based alkali that are present in plant and wood material, from our ashes by leaching.  To begin, make a container with a small hole (or several holes) punched through the bottom.
  2. Place a one-inch layer of small gravel into the bottom of the container.
  3. Place a one-inch layer of sand or straw on top of the gravel. Note: the gravel and sand function as filters. If you cannot find these substances, any type of filter material placed over the hole will suffice.
  4. Fill the rest of the container with ashes from a cooled campfire.
  5. Place a cooking container under the first container to catch the runoff.
  6. Slowly pour about a gallon of water onto the ashes allowing the brownish-gray water (which is lye) to exit the hole in the container and into the second container. Pour slowly, about 2-3 ounces per minute. If the ashes begin to “swim”, you are pouring the water in too fast. During this “leaching” of the ash, if the lye coming out starts to lose its color and become clear, more ash can be added as needed.
  7. Boil the lye water in your cooking container until more than half of the water has evaporated. The mixture may foam or froth with small bubbles rising up the sides of the pot. The resulting solution is potassium carbonate or potash.
  8. Add 1 ½ cup lard, grease, or animal fat to the boiling mixture and continue cooking for about 30 minutes. If animal fat is used (which is a likely scenario if you’re making the soap in the wilderness), ensure it is free of blood, meat, or food particles (which may be present if the animal fat was obtained from a recently cooked meal).  If the animal fat is not pure, the soap may spoil during the drying process.
  9. Place the mixture into molds. The shape of the mold does not matter and a simple wooden mold carved from tree wood will suffice. A large mold can be used too and the resulting bars cut into pieces using a wire or fine cord after the soap has hardened.
  10. Allow the mixture to dry for about 2 days. Remove the soap from the mold. The soap will have likely shrank so it should be easy to remove from the mold.
  11. If a large mold was used, cut the soap into smaller bars.
  12. Place the soap bar(s) in a well-ventilated area and leave for about 10-14 days.  If there are many bars, do not stack them but rather, lay them flat to aid in the drying process.

Additional notes about making soap in the wild

Animal fats used in the soap making process

Old lye-making barrel used to leach lye from wood ashThe cleaner the animal fat (called “tallow” if it came from cattle or “lard” if it came from a pig) used in the soap-making process, the better smelling (and pure) the soap will be. Animal fats can be cleaned by a process known as “rendering”. Rendering removes all of the animal meat tissue that may be embedded or surrounding the animal fat.

To render fat into more pure form, put the fats (which should be chopped into small pieces) and/or cooking grease into a cooking container and add an equal amount of water. Boil the mixture until all of the fats and grease have completely melted. Remove the mixture from the fire and add more water to replace water that has boiled off. Allow the solution to cool overnight. By the following day, the fats will solidify and float to the top forming a very clean later of fat (impurities and animal meats will sink to the bottom). The more times this process is repeated, the purer the resulting fat residue.

Softness and hardness of the resulting soap

If the resulting soap bar seems to be too soft, next time toss in a bit of salt (called “graining” the soap) during the boiling process. The salt will absorb some of the water and will help harden the soap giving it a texture and feel similar to commercial soaps. Often times the soap-making process can be impacted by the type of water that is used in the mixture. Purer water from a spring or rain water (soft water) works best because it does not have many metallic or acidic chemicals present. Well or river water (hard water) can be used too but may require salt or baking soda to harden the soap. During the cooking process, you can tell if the water is ideal or not – water with ideal properties will produce more “soap bubbles’ present during the cooking process.

Making the soap smell good

Natural fragrances can be added to the mixture to scent the soap. For instance, oil squeezed from lavender or wintergreen can be added to the mixture to make the soap smell like a commercial soap. Vinegar or lemon juice can also be added to rid the soap of any undesirable smells.

The proper strength of lye

In the early steps of the process, when the lye solution is leached out of the ashes, the strength of the lye is determined. Pouring the resulting solution back through a new container of ashes will strengthen the lye (and thus, make it more caustic). In turn, pouring the solution more quickly through the ash will weaken the lye solution.

Getting the correct strength of the lye solution is the most difficult, and variable part of the soap-making process. An uncooked egg (or potato) can be floated in the solution to test the lye water’s strength (or a feather can be used – it should begin to dissolve when placed in the lye solution). The lye is considered to be the correct strength if an area of the egg about the size of a quarter bobs above the surface of the water (you might want to toss the egg afterwards since it’s been floated in caustic lye).


If the lye solution is too strong, add more water. If it’s too weak, you can boil it longer to strengthen it. If too much lye is left in the soap it will “burn” the skin when used and may not solidify as well when setting.

Safety note: lye water can be dangerous and should be stored away from children and animals.

Other uses for lye water

Lye water itself can be useful in the wilderness and can be used to sanitize (it kills bacteria) outhouses and latrines.

What is Potash and pearlash?

Women in the early 1900's making soap at homePotash is the residue that remained after boiling off the water in the lye solution. Pearlash is a more purified form of potash and is created by baking the potash in a kiln until the carbon impurities have burned off leaving a white powder. This white powder not only makes extremely pure soap but can also be used glass making.

The best lye ashes

White ashes make the best lye ashes meaning ashes from a very hot fire work best. The best woods for producing white ash are palm, dried out banana peels, kapok tree, oak tree, hickory, ash, beech, and apple tree wood. Still, any wood ash from a hardwood tree (or a softwood tree if you want softer soap) will suffice for soap made in the wilderness. Even ashes from kelp or seaweed will work.

Using plant oils rather than animal fat

Plant oils can be used instead of or in addition to animal fat in the soap-making process. The best oils for soap making include coconut oil, shea butter, cocoa butter, and sun flower oil although any vegetable oil will suffice.

Green soap

When the soap is first poured into the molds, it is in a form called “green soap”. At this state, the soap can be caustic so if your hands are sensitive, be careful when handling it.

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