Ever wonder how to make liquid soap? It is a fairly easy process which you can do from the comfort of your own home. All you are really going to need is a bar soap of your choice, some sort of container and water! You can make it more difficult for yourself by making your own bar soap, but that will be another topic altogether. Let’s learn how to make liquid soap from a soap bar.

However, if you do have a passion for chemistry magic, you can give making the liquid soap with basic materials you can usually from the pharmacist such as potassium hydroxide. Go to Part 2 to learn how to do it this way!

Part 1: How to Make Liquid Soap with a Bar Soap


  • Distilled water

  • A container (e.g. bowl)

  • A bar soap

  • Cheese grater

  • Blender

Optional ingredients

  • Essential oils

  • Natural food coloring

  • Honey


  1. Find a bar soap you are going to use, any kind of bar soap. Be it half used or leftovers, all can be turned into liquid soap for your personal use. Consider the function of the final product too. If the base soap you are using is meant for a facial wash, then the liquid soap made from it should only continue to be used for the face. If you want to have your own customized scented or colored liquid soap, then use an unscented bar soap or one with a relatively plain color, e.g. white.

  2. Grate the bar soap into the container. A fine cheese grater is recommended for this step. Make sure to grate all the bar soap you are using. The finer the grate is, the better the soap will melt and the faster it will be done. Chop the bar in chunks for easier grating. Aim for one cup or so of the soap flakes, or about one average soap bar.

  3. Boil the distilled water and pour the water into the soap flakes. Make sure the water to soap ratio is one to one, i.e. one cup of water to one cup of soap. Pour the mixture in a blender and whip it to a pasty consistency.

  4. Alternatively, you can use a microwave instead. Boil a cup of water in a microwave (use a microwave safe dish), then add the soap flakes. Let the mixture melt for two minutes or more. Then place the mixture in the microwave. Heat the mixture up for thirty seconds at a time, and continue to do so until it reaches the consistency of paste.

  5. Customize the liquid soap! Get creative with your liquid soap. If you did start with plain colored and unscented soap bar, this step will be what gives life to your liquid soap. Consider the following ingredients to enhance your very own liquid soap!

  • Essential oil of your choice (lavender, tea tree, etc.) for scent. A few drops are enough.

  • Food coloring for color. Try 1 drop of green and 2 of blue for a cool aqua.

  • Honey for additional moisturizing effect.

Part 2: How to Make Liquid Soap from Basic Materials



  • Slow cooker

  • Stick blender

  • Quart jar or wide mouth jar

  • Stirring spoons

  • Kitchen scale

  • Thermometer

  • Ladle

  • Potato masher

  • Large jar

  • 7 ounces coconut oil

  • 16.5 ounces olive oil

  • 5.5 ounces potassium hydroxide

  • 16.5 ounces filtered or distilled water

  • 40 ounces filtered or distilled water

  • 6 ounces filtered or distilled water

  • 3 ounces borax

  • Large pot with lid


Optional ingredients

  • Essential oils

  • Natural food coloring



  1. Pretend that you are baking a cake, which means that all the ingredients should be measured close to the weight required for the best results. Pour the coconut oil and olive oil into the slow cooker. Turn on the heat to low.

  2. In the quart jar, add 16.5 ounces of water. Slowly stir in the potassium hydroxide, be gentle for this step. You will hear some popping sound from this process due to the reaction the chemical had with water.

  3. Once you had the two ingredients mixed together (i.e. clear solution), pour in the solution into the oil mixture in the slow cooker. The heat would not be a problem here yet.

  4. Hand stir the mixture carefully for five minutes. This is to make sure that the oils have contact with most of the potassium hydroxide.

  5. Followed by stirring the mixture with a stick blender. This step might take around thirty minutes to achieve what in the industry is known as “trace”. Usually, it will look like vanilla pudding, but since we are using potassium hydroxide, the mixture should resemble applesauce.

  6. As you stir, the solution will constantly look it they are going to separate. Don’t stop until the separation stops or you reached the “trace” consistency.

  7. Close your slow cooker and cook them for thirty minutes. If they separate, stir them and close the lid. You are going to do this step every thirty minutes for the next three to four hours.

You will expect the mixture to look like the following during the cooking stage:

  • Applesauce

  • Custard, small bubbles at the top

  • Mashed potatoes with too much milk added in

  • Taffy

  • Creamy, chunky petroleum jelly

  • Translucent petroleum jelly

Each stage should be achieved every thirty minutes or so. Time is your best friend here. Every stage should be easy to stir with the spoon or blender, except on the taffy stage. For this stage, make use of a potato masher instead.

Once you reach the last stage, i.e. translucent petroleum jelly, it’s time to test it. Dissolved in two ounces of boiling water with one ounce of the soap paste, let them sit for two minutes or more. The mixture is ready only if it turns slightly cloudy or clear. If you did find it milky or very cloudy, cook it for another thirty minutes. Continued testing and cooking. If it remains cloudy, then you probably mismatched the ingredients, you can, however, still continue the steps but only use the soap for laundry detergent.

Once you had your clear tested mixture, boil 40 ounces of water in a pot. Make sure it has a lid. Pour in the entire soap paste and stir well. The potato masher is going to help a lot at this step. When they are fully incorporated, turn the heat off and put on the lid. Now wait for an hour.

After an hour of waiting, stir the mixture. If they are goopy or chunky, let them sit longer. You can also leave the mixture overnight.

Once the mixture is smooth and chunk-free, grab your borax to neutralize the mixture. Two ounces of boiling water need to be added to one ounces borax, in order to make the borax dissolved and to keep the solution hot. You will generally need two ounces of the solution. Add the solution to your soap paste, half an ounce each time. Mixed them and it is time to add the scent and color to your liquid soap (use the essential oil and food coloring)

Now for the longest wait time. Ladle the soap into your storing jar. Tightly secure the lid and have it rest for another week. This is to make sure any solid particles will sink to the bottom. At the end of the week, the soap will look much clearer.

Your soap is now ready for use. The only thing left to do is transfer them into smaller bottles for convenient use!


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