Home crafts: making homemade lye soap

A guide to making your own lye soap at home with commonly available ingredients.

Photo Credit: Laura Stone
By John Casteele

There are few home craft projects more interesting or useful than making your own lye soap. Not only is it a chance to see exactly how soap is made, but you end up with a product that everyone in your family can make use of! Of course, the best part is that making your own soap isn’t even that difficult… mostly it just takes some time, and a little bit of care.

The first thing that you’ll need when making your own soap are a few ingredients and other essentials. You’ll need to get the following:

1 can lye crystals
2 1/2 pints cold water
5 1/2 lbs. cooking fat or lard
scented essential oil (such as lavender)
food coloring or pigment (to match the scent of the oil)
glass bowls
wooden spoons
glass pans or soap molds
wax paper
safety glasses
rubber gloves
glass cooking thermometers

Start by adding lye to your water, putting the water in one of your glass bowls and pouring the lye SLOWLY into the water. Be sure to wear your safety glasses and gloves, and watch out for splashes–lye is very caustic, and can cause severe burns if it gets on your skin or in your eyes. Stir the lye water with a wooden spoon until all of the crystals have dissolved; the temperature will begin to rise, so don’t worry that you’re doing something wrong. Set the bowl with the lye water aside to cool, and begin to melt your fat or lard.

Once the fat has melted and both it and the lye have cooled to between 85 and 100 degrees, it’s time to begin mixing the two. Making sure that you’ve got your safety glasses and gloves on, pour the liquid fat into another glass bowl, and slowly begin adding your lye water. Again, take great care in pouring the lye, and do so in a well-ventilated area. Use a wooden spoon to mix the fat and the lye, continuing to mix until the lye-fat mixture begins to “trace”… in other words, when you move the spoon through the mixture and you can see the path of the spoon for a few seconds afterwards. This is also when you should add your fragrance oil (a few drops will do it) and colorings (again, only 1 or 2 drops should get the job done.) Be careful with both, since you don’t want the scent to be overpowering and you definitely don’t want the soap to color the skin of the person using it.

Once your soap mixture is tracing, pour it into your molds or into a glass pan that you’ve greased and lined with waxed paper. Place additional wax paper on the top, and wrap the mold or pan in towels so that they can cool and set up overnight. After they’ve set up, remove them from the molds or remove the block from the pan and cut it, and then place them on a rack in a cool, dry place so that the bars can harden over the course of the next two or three weeks. After they’ve had sufficient time to harden, feel free to use the bars or to give them to friends and relatives.