How to Make Salt Soap Bars

If you're looking for a way to combine the cleansing, exfoliating, and detoxifying qualities of a salt bath with handmade natural soap, look no further than a salt soap bar. It combines the best of both natural soap and a sea salt bath. The final bar is super-hard and produces a lotion-like creamy lather. With a few exceptions, you can make salt soap bars in the same way as any other cold processed soap.

What You'll Need

Equipment / Tools

  • Large pot
  • Spoon
  • Soap molds

Materials

  • Coconut oil
  • Palm oil
  • Olive oil
  • Castor oil
  • Lye solution
  • 24 ounces to 2 pounds salt, depending on preference

Instructions

  1. Pick Your Salt

    You can use regular, fine-grain sea salt for salt bars. You can also select a pink, Himalayan, or another specialty salt, as long as it doesn't have high "other" mineral content, such as dead sea salt. Don't use Epsom salts—the magnesium in the bars makes them gooey messes.

  2. Determine the Recipe

    The first thing to do is create the recipe you're going to use for the soap. For these bars to lather at all, you need to use a lot of coconut oil. An example of a basic recipe uses 30 percent coconut oil, 30 percent palm oil, 35 percent olive oil, and 5 percent castor oil.

    However, a salt bar recipe example looks more like this: 75 percent coconut oil, 10 percent palm oil, 10 percent olive oil, and 5 percent castor oil, though some simple recipes are just 80 percent coconut and 20 percent olive. Some soap-makers feel that more complex combinations of oils make a better lather, so feel free to use your own mix of oils.

    Tip

    You can add colorants and additives to salt bars just like other soap. Keep in mind, however, that you don't have a lot of time to manipulate the soap and it's going to thicken quickly.

  3. Mix the Lye Solution

    Mix your lye solution, measure and melt your oils, and blend the lye and the oils just like you would in any other cold process soap batch.

    Tip

    When you adjust or change an ingredient in your recipe, run the new recipe through a lye calculator.

  4. Add the Salt to Your Salt Soap Bar Batch

    Once the soap has reached a really light trace and you've added your fragrance or essential oil, it's time to add the salt. There are three general models when it comes to the amount of salt used in salt bars:​

    1. One hundred percent of the soap amount: If your recipe makes 2 pounds of soap, you add in 2 pounds of salt. This method is the hardest and saltiest but has the lowest lather.
    2. One hundred percent of the oils in the recipe: If your recipe has 24 ounces of oil in it, add in 24 ounces of salt. This creates a good balance of salt and lathering ability.
    3. A lesser amount of salt: Some soap makers will do 50 to 70 percent of the total oils and are happy with their bars. This has the least salt but is the most like normal soap.

    Dump the salt into your soap pot and start stirring vigorously.

    adding the salt to the soap batch
    David Fisher
  5. Pour the Soap

    Pour or scoop the soap into your mold. It will be a lot thicker than your normal batches of soap. After you've poured the soap, it helps to tap, thump, or slam the mold onto the counter to help dislodge any air that may have gotten trapped under the soap.

    scooping the salt bar soap into the mold
    David Fisher
  6. Cut the Soap Sooner Rather Than Later

    The salt soap will start to harden almost immediately. If you're using a log mold, cut the soap as soon as it's firm enough. The soap will still be warm even as it's going through the saponification process. However, if you wait too long, the soap will be hard, difficult to cut, and result in crumbly bars.

    salt soap bars
    David Fisher
  7. Use Divider Molds or Single Cavity Molds

    Another option for salt soap bars is divided slab molds or single cavity molds where each mold holds one bar of soap. With the slab divider mold, line the bottom of the mold with freezer paper or you'll have a very hard time getting the bars separated from the bottom of the mold. With single cavity molds, you don't have to rush. Let the bars set and cool overnight. They should pop right out of the molds quite easily.

    salt bar batch using slab divider mold
    David Fisher