How to Make Salt Soap Bars

How to Make Salt Bars

salt soap bars
A variety of salt soap bars. David Fisher

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 bar."

Salt soap bars, or salt bars, combine the best of both natural soap and a sea salt bath. The final bar is super hard and produces a lotion-like creamy lather. Make them like any other cold processed soap with three big exceptions:

  1. Adjust the recipe so that it contains at least 70 to 80 percent coconut oil. The salt counteracts the lather of the soap, so the high coconut amount is needed to make lather.
  2. Add salt at trace, even though it will seem like a lot of salt. There are three general models when it comes to the amount of salt used in salt bars:​
    • 100 percent of the soap amount. If your recipe makes 2 pounds of soap, you add in 2 pounds of salt
    • 100 percent of the oils in the recipe. If your recipe has 24 ounces of oil in it, add in 24 ounces of salt
    • Some lesser amount of salt. Some soap makers will do 50 to 70 percent of the total oils and are happy with their bars.
  3. Unmold and cut the soap as very soon as it sets up, often in as little as two hours after pouring.

Create Your Salt Bar Soap Recipe

mixed soap ready for the salt to be added
David Fisher

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.

A basic recipe is one like this:

  • 30 percent coconut
  • 30 percent palm
  • 35 percent olive
  • 5 percent castor

A salt bar recipe should be modified to this:

  • 75 percent coconut
  • 10 percent palm
  • 10 percent olive
  • 5 percent castor

Some simple recipes are just 80 percent coconut and 20 percent olive. Some soap makers feel more complex combinations of oils make better lather. Feel free to use your own mix of oils. As always, when you adjust or change an ingredient in your recipe, be sure to run the new recipe through a lye calculator. 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.

Add the Salt to Your Salt Soap Bar Batch

adding the salt to the soap batch
David Fisher

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. The three theories of salt addition tend to yield different results. Method #1 is the hardest and saltiest but has the lowest lather. Method #3 has the least salt but is the most like normal soap. Method #2 is a good balance of salt and lathering ability. There's no special technique necessary to add the salt, just dump it into your soap pot and start stirring vigorously.

Pour the Soap

scooping the salt bar soap into the mold
David Fisher

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/slam the mold onto the counter to help dislodge any air that may have gotten trapped under the soap.

Cut the Soap Sooner Rather Than Later

salt soap bars
David Fisher

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

Using Divider Molds or Single Cavity Molds

salt bar batch using slab divider mold
David Fisher

Another option for salt soap bars is divided slab molds or even single cavity molds where each mold holds one bar of soap. With the slab divider mold, be sure to line the bottom of the mold with freezer paper, otherwise, 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.

Soap Making Tips

Use these helpful hints for successful salt soap making:

  • Use regular, fine grain sea salt for salt bars. You do not want to use Epsom salts. The magnesium in the bars makes them gooey, sweaty messes.
  • You can use pink, Himalayan, or other unique soaps as long as they don't have high "other" mineral content, like dead sea salt.
  • You can add colorants and additives to salt bars just like other soap. You don't have a lot of time to manipulate the soap and it's going to thicken quickly.
  • Some folks find that the salt seems to lessen the fragrance oil effectiveness.

Enjoy this exotic and fun soap variety!