How to Rebatch Homemade Lye Soap
Saponification is the chemical reaction that occurs when fats and oils, lye and water are mixed. The end result is soap. Rebatching is essentially melting down soap a second time to add ingredients, pour into fancy molds, or make it last longer. Rebatching soap and hand-milling soap are two phrases that mean the same thing. Good, usable soap can be hand-milled. Usable soap that is perhaps misshapen or ugly can be hand-milled and poured into fancy molds. Caustic batches of soap that are not usable, however, must be thrown away.
Things You'll Need
- Batch of finished soap
- Sharp knife
- Cheese grater
- Kitchen scale
- Measuring cup
- Cooking pot
- Wooden spoon
- Candy thermometer
- Additives (optional)
- Soap molds
Instructions
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1
Start with a finished batch of soap. Cut into smaller blocks with a sharp knife. Grate with a cheese grater.
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2
Place the cooking pot on your kitchen scale and set it to read 0. Place the grated soap in the pot and weigh it. For every 12 ounces of soap, fill the measuring cup with 9 oz. water and add it to cooking pot.
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3
Place the pot on the stove over medium heat. Heat the soap until it melts and reaches between 150 and 160 degrees F. Stir gently with the wooden spoon while it's melting; vigorous or too much stirring will result in a layer of suds on top.
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4
Add optional ingredients such as essential oils or finely ground oatmeal.
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5
Pour the mixture into molds, and place the soaps in the freezer for a few hours. Remove them from the freezer when they are hard, and pop them out of the molds.
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6
Allow the bars of soap to air dry for a couple of weeks.
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Tips & Warnings
As the rebatched soap dries, it may change shape. The soap is still good.
Keep soap-making supplies and other kitchen supplies separate.
