Lye, fat and water are the three basic ingredients that combine to make soap. Lye dissolves protein and oily deposits, lending itself to cleaning applications in the home as well as being one of the main ingredients in making soap. It is a common ingredient in oven cleaners. Lye can strip paint finishes, but will leave wood grain raised. Lye dissolves protein and oil -- meaning it can degrade soap and hair -- making it useful as a drain cleaner.
Chemically, commercial lye and homemade lye are different. The chemical name for lye made with wood ash is called potassium hydroxide. Lye manufactured for retail is called sodium hydroxide. These products require different measures for the same application. The amount of lye you use in a recipe varies based on which product you are using.
Hardwoods such as oak and maple or fruit trees like apple are the best sources for ash to produce a good quality lye. Evergreens and pine trees are not suitable woods for ash for this purpose. A consuming fire with lots of air should be used to produce thin, white papery ash free of charcoal chunks.
You will need enough ashes to fill a lye-safe, waterproof container (non-metal) to within three to four inches of the top rim. Ash containers may be large (wooden barrels) or small (5 gallon buckets).
Get 2 containers that are not metal. One bucket will hold the ash, the other container will catch the runoff. At the base of the ash container drill a small hole. The opening should be small enough that it can be sealed with a toothpick, a piece of corking or a wooden rod -- something which is not metal.
A layer of small pea gravel should be placed in the bottom of the ash bucket. Top this with a four inch layer of packed hay, grass or straw. Pressing down firmly, fill the rest of the bucket with your wood ashes. Be sure to stop 3 or four inches below the top.
At least five gallons of soft water will be needed, possibly more. Water which is soft has few metals and minerals. Sources of soft water include water that is specially filtered, from sandstone, peat or lava rock (granite, for example). Another alternative is to distill the water you have. However, the simplest way to acquire soft water is by collecting rainwater.
Be cognizant that the location of your container should be well away from animals or children that could upend it. The drainage can be caught in a glass jar, wooden bucket, or an enamel coated pan. Don't use metal or the lye could burn a hole in it. Find a position for this catch container that is close enough to the ash bucket to prevent unnecessary splashing during drainage.
Lye may cause blindness. If swallowed it can be fatal. It is possible for lye to sear all sorts of surfaces, in particular fats and oils on the skin. The chemical action of lye with fats and oils creates salts which can result in severe burns, permanent injury and scars. Lye burns can be so severe as to cause nerve damage, so you may not feel the burn right away.
Safety precautions should be undertaken before beginning. Work in a well ventilated area. Have contact information for emergency services and poison control on hand. Dress appropriately. Don't expose your arms and legs by wearing short sleeves or shorts. Protect your eyes with safety glasses and your hands with rubber gloves. A container of vinegar should be within reach to neutralize burns to the skin. Do NOT wash with water following contact with this substance as this will merely exacerbate the corrosive affect.
Create a recessed spot in the surface of the ash using a dowel or other wooden rod. Heat 1 gallon of soft water to boiling. Carefully pour this into the ash bucket. The ash and water will spit, spew and bubble. Wait until this simmers down before adding another gallon of soft water. The ashes may settle to a lower level. Add more ash to the container to keep it filled. Repeat this process until the ashes in the container are covered with water. Close the lid on the container.
Unstop the drain hole you drilled into the ash container and allow the liquid to runoff into the other container. A full day may be required for this.
On the second and third day, pour the water that has runoff of the ashes back through again. This will add to the strength of your lye.
A variation of this method is to leave the bucket sitting without draining it. Seal the bucket and leave it for three days in a place where it will not be disturbed. Take care that you choose a location where the bucket won't be tipped. After this time you should drain the bucket.
The resulting liquid is lye water (potassium hydroxide). To test its strength place a fresh egg (still in its shell) into the liquid. If your lye solution is the right potency, the egg will float exposing a nickel or quarter sized portion of its shell above the surface. This equals an area of 2 to 2 1/2 centimeters in diameter. A weak lye solution won't work well in most soap recipes. A weak lye solution will allow the egg to sink. If the egg bobs on top of the surface, the lye is too strong and needs diluting with more rainwater. Destroy and discard the egg when you are finished.
Heating weak lye water will strengthen your solution by reducing the water content. Enamel finished pots have a protective coating that covers the metal, making them safe to use for this purpose, though they may not be utilized again for food preparation. Take care not to scorch lye when heating your solution. If a chicken feather starts to melt when held to the hot liquid, you know your solution is the right strength. Set the pan of lye water aside to cool.
Store lye water in jars with plenty of head room to allow for safety in pouring. Close jars firmly and store them in an unlit, cool area where curious children haven't any access.
Dig a hole in an out of the way area to dispose of the spent ashes. When the ashes are cool, the hole may be safely filled.
To make potash crystals, place the lye water in a safe container. You'll find that glass is a good choice for this project. Left in the sun, uncovered, the water will evaporate and crystals will form. Follow the same storage precautions with potash crystals as you would the lye water.
This and other skills are discussed in the new book, The Vision by Debi Pearl, the compelling new novel from international best-selling author who also co-wrote To Train Up A Child and the Good and Evil comic.