How to Make Bastille Soap for Sensitive Skin

By
David Fisher
David Fisher

David Fisher is a highly regarded professional soaper with over 15 years of experience, sharing his knowledge of the craft, science, and chemistry of saponification. He currently owns Bath Rabbit Soap Company and is the author of "The Complete Photo Guide to Soap Making."

Learn more about The Spruce Crafts' Editorial Process
Updated on 09/16/20
white soap bars

ondacaracola photography / Getty Images

Project Overview
  • Total Time: 2 hrs
  • Yield: 12 bars (approximately 3 pounds of soap)
  • Skill Level: Beginner
  • Estimated Cost: $20 to $30

Most soap recipes carefully balance the soap's cleansing ability with its moisturizing effects. For instance, cleansing can be accomplished by the abundant bubbles of coconut or palm kernel oil, while moisturizing is achieved through combinations of olive oil, shea butter, and more. However, some people with sensitive skin might find soap with strong cleansing power irritating and must choose a more moisturizing soap, such as Bastille soap.

This Bastille bar soap recipe contains roughly 70% olive oil (as well as roughly 10% shea butter for an added moisture boost), but it still mildly cleanses thanks to the low amounts of coconut and castor oils in it. The steps to make it are fairly quick and easy to follow. Then, the soap bars need four to six weeks of curing to harden. But after that, this mild soap is a great treat for your skin, and the bars make wonderful homemade gifts as well.

DIY Basic 4-Oil Soap Recipe

What You'll Need

Equipment / Tools

  • Kitchen scale (with ounces)
  • Bowls for measuring ingredients on scale
  • Safety gloves and goggles
  • Pitcher (for lye solution)
  • Teaspoon
  • Stainless steel spoon
  • Liquid cooking thermometer
  • Medium-size microwavable bowl or pot
  • Immersion blender
  • Soap bar mold

Materials

  • 10 ounces distilled water
  • 2 teaspoons sugar
  • 1 teaspoon salt
  • 5 ounces lye flakes
  • 6 ounces coconut oil
  • 4 ounces shea butter
  • 28 ounces olive oil
  • 2 ounces castor oil
  • 1 ounce essential oil of your choosing (optional)

Instructions

  1. Mix the Lye Solution

    First, make the lye solution. Put on your safety gloves and goggles. Then, add the salt and the sugar to the distilled water in your pitcher, making sure they are both completely dissolved. Gradually add the lye flakes to the water, and gently stir with your stainless steel spoon until the lye is completely dissolved.

    Lye creates heat as it dissolves, and adding it too quickly or stirring too fast can cause the water to boil over. Likewise, adding water to lye rather than lye to water can cause it to have a volcano-like reaction and bubble over.

    After the lye has dissolved, set the solution aside in a cold, secure spot to cool. Also, wash your spoon and anything else that has come in contact with the solution to avoid spreading it. (You will need the spoon to stir ingredients later.)

    Warning

    Lye is a dangerous chemical that can burn the skin and eyes and is harmful when inhaled. Always wear protective gear when using lye, and work in a well-ventilated area.

  2. Melt the Coconut Oil and Shea Butter

    Measure the coconut oil and shea butter. Then, melt them in the microwave or on the stovetop.

  3. Add the Olive and Castor Oils

    Measure the olive oil and castor oil. Then, add them to the melted coconut oil and shea butter either in the microwavable bowl or pot, stirring well.

    Tip

    If you wish, you can use an oil that's been infused with a skin-friendly herb, such as lavender or chamomile.

  4. Mix the Oils and Lye Solution

    When both the oil mixture and the lye solution have cooled to about 100 degrees Fahrenheit, it's time to mix them. Slowly add the lye solution to the bowl (or pot) with the oils, and give the mixture a few short bursts with an immersion blender.

  5. Add Fragrance (Optional)

    If you want to add essential oil for fragrance to your bar soap, now is the time to do it. Simply add it to the mixture, and stir well. This is also the step to incorporate any other desired additives, such as chamomile or lavender flowers. However, if you're making this soap for someone with sensitive skin, make sure they aren't sensitive to the additives.

  6. Mold the Soap Bars and Let Them Cure

    Finally, pour the mixture into your soap bar mold. An olive oil soap like this will be soft initially, but after four to six weeks of curing, it will get nice and hard. The lather will be milder and less bubbly than a bar soap with more coconut oil in it.