How to Make Liquid Soap From Bar Soap

Learn how to turn a single bar of soap into bottles of liquid lather

Person washing their hands

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You can either make all-natural liquid soap from scratch or stretch a single bar of soap into a few bottles of liquid suds using a quick DIY process. Making liquid soap from a bar is a simple life hack that takes substantially less time and uses fewer tools and ingredients than it does to make a scratch recipe. All it takes is around 10 minutes of prep time, a few supplies, and you're ready to make your first batch.

Supplies for the Soap

  • Bar of soap (scented or unscented, any brand)
  • Knife, cheese grater, potato peeler, or food processor
  • Water (distilled water is optional)
  • Essential oils (optional)
  • Soap coloring (optional)
  • Saucepan or pot
  • Empty non-food soap dispensers/bottles

Prep and Cook the Soap

Take a typical 4-ounce bar of soap and grate or finely chop it up by hand or food processor to make the soap flakes. For one bar of soap flakes, you'll need to boil a half gallon (64 fluid ounces or eight cups) of water. Put the grated or chopped soap into a large bowl that will be specifically used for making the mixture.

Bring the water to a boil on the stove. Tap water is fine to use for this recipe, but distilled water is pure, which is why many soap makers prefer to use it in their recipes. You can also take it a step further and make a rain barrel to collect rainwater for extra soft soap.

Turn off the heat, pour the boiling water into the bowl of soap flakes and stir to melt using a whisk or a large spoon. Keep stirring to combine. At this point, the mixture will have a thin consistency. Allow the mixture to cool for at least 15 minutes. Then, stir it again. The mixture should be slightly thicker now.

Rest the Soap

Cover the bowl of soap and allow it to cool for 12 to 24 hours. After the soap has rested, stir to check it for consistency. The goal is to have a bowl of congealed soap. If the mixture seems too thin, reheat it and add a bit more soap flakes. If the mixture seems too thick, reheat it and add a bit more water. The moisture content varies from one brand of bar soap to the next, so you'll likely need to tweak the recipe to get it to your preference.

Finalize the Soap

Before pouring your soap into dispensers, you'll have the chance to make the consistency super smooth. Run your finished liquid soap through a blender or use an immersion blender to smooth it out. Once you are satisfied with the consistency of your liquid soap, add a few drops of essential oil and/or coloring, if desired.

If you're using a fragrant bar of soap for your recipe, you might not want to add any fragrance. If you do add fragrance, add it in sparingly so it won't affect sensitive skin. If the soap is to be used by children, use even less essential oil in the recipe. Consider using safe, non-toxic essential oils with antibacterial properties, such as lavender, lemon, eucalyptus, or peppermint for an extra treat.

This type of DIY liquid soap stores well. From one bar of soap, you'll probably produce enough liquid soap to fill four or more of your favorite soap dispensers. Pour your soap into labeled toiletry bottles/dispensers. Enjoy it for weeks to come, thinking of all the money you saved!

Foaming Hand Soap

If you love the look and feel of foaming hand soap, all you need to do is put your liquid mixture into a special foaming soap dispenser that you can repurpose or buy at a craft or household goods store.