How to Make Lye for Soap Making

Soap makers who use either the cold or hot process methods know how to use lye. This lye is usually store bought, and is also known as caustic soda. However, did you know that lye can be made at home? If you've ever wondered how lye is made, wondered how colonial soap makers made their own lye, or if you simply feel it is important as a soap maker to understand how to make lye for soap making, then you will be happy to read this article!

The type of lye that can be made at home is caustic potash, also known as potassium hydroxide. This is different from the lye you buy in stores, though both of these are types of lye for soap making. Caustic potash is the same type of lye colonial soap makers used to make their soap. It can be used in soap making as well as in the production of biodiesel. So if you're into helping out the environment, this article will be doubly useful!

To make your own lye, you need to prepare the following materials:

  • a rain barrel

  • a wooden barrel

  • a cork

  • a drill

  • hollow blocks

  • river rocks

  • hay

  • hardwoods for burning

  • a pan

  • airtight containers


Then, follow this procedure:

  1. Use your rain barrel to catch rain. The objective here is to store about 2-3 gallons of soft water.

  2. With your drill, put a hole on your wooden barrel (the hole should be about 2 inches from the bottom of the barrel.) Make sure the cork fits around this hole well (enough to stop liquid.)

  3. Place the barrel on top of hollow blocks so as to elevate it. Make sure the entire setup is in a safe place, away from children and animals, or where it may get tipped over. Try not to leave it outdoors.

  4. Cover the bottom of the barrel with river rocks. Make sure it is lined with these rocks well. Then, cover the rocks with six inches of hay.

  5. In a separate container (you can do this in a pit or fireplace), burn your collection of hardwoods. Remember to stick to hardwoods and not to use any of the evergreens. Burn these until the woods are completely dry and brown. Wait for the ashes to cool. Completely.

  6. Take the ashes you can collect from this fire and put them in your barrel. The most that you can fill your barrel with ash is about 1/3 the way to the top.

  7. Remove the cork and put a pan underneath it so it can catch the liquid. Pour in the soft water and wait till you see it begin to trickle out or till it's about six inches from the top of the barrel. Once it reaches this level or begins to trickle out, stop pouring, and cork the barrel. Cover the top of barrel as well.

  8. Leave your barrel for about four days. You can add ash everyday after the first day (by this time the initial ash would have settled. Just be sure to drain it on a specific day that week.

  9. Check to see if your lye is ready by dropping an egg into the barrel. If it floats enough so that the part above water is as about as big as a quarter, then the lye is ready. If this doesn't happen, you will need more ash or drain all the water and re-leach the lye by pouring the drained water back into the cast and setting one more cycle.

  10. If the lye is ready, however, drain your lye out into containers by putting your containers under the tap and pulling the cork free. Remember not to fill your lye containers to the brim. About 2/3 full is ideal.

  11. Store your lye in a cool dry place.

Try to use your homemade lye soon. Homemade lye is really only economical if you are a serious soap maker and will be making very large batches of soap. If you are an occasional soap maker, on the other hand, this process might be too tedious for you to invest in or follow. When you make lye for soap making, remember to be very careful throughout the entire process. Making lye is even more dangerous than handling it. If any of it comes into contact with your skin or eyes, seek medical attention immediately

Finally, throw whatever has been left over in the barrel. Make sure you ditch it relatively far from your home and anything that may be important. For example, the corner of your backyard, may be an okay spot for as long as no pipes are passing through there. Create a hole in the ground and pour the waste into this hole. Make sure not to cover the hole entirely, though. You have to wait till it's all dried up, then you can cover it up with soil again.