Simple Castile Cold Process Soap Tutorial
Serves: About 2-3 pounds of soap
This soap is made with 100% olive oil, which is called Castile soap. It's scented with Tomato Fragrance Oil which is light and herby.
  • 10″ Silicone Loaf Mold
  • 35 oz. Olive Oil
  • 4.5 oz. Sodium Hydroxide Lye
  • 9.2 oz Distilled Water (20% water discount)
  • 2 oz. Tomato Leaf Fragrance Oil
  • Savon Soap Stamp
  • Optional (but highly recommended!): Sodium Lactate
SAFETY FIRST: Suit up for safe handling practices! That means goggles, gloves and long sleeves. Make sure kids, pets, and other distractions and tripping hazards are out of the house or don’t have access to your soaping space. Always soap in a well-ventilated area.
FRAGRANCE PREP: Measure 2 ounces of Tomato Leaf Fragrance Oil into a glass, fragrance oil safe container. Set aside.
  1. Slowly and carefully add the lye to the water and gently stir until the lye has fully dissolved and the liquid is clear. Set aside to cool. For this recipe, I highly recommend using sodium lactate. Sodium lactate will hep you remove the soap from the mold much faster. Use 1 teaspoon of sodium lactate per pound of oils in the recipe. For this recipe, you’d add about 2 teaspoons sodium lactate. Add the sodium lactate to the cooled lye water.
  2. Pour the olive oil into your mixing bowl, and heat to 120-130 degrees. Once the lye water and the oils have both cooled to about 130 degrees or below (and are ideally within 10 degrees of each other), add the lye water to the oils and stick blend until you reach a light trace. This may take a little longer than usual, since this recipe is 100% olive oil!
  3. Add the Tomato Leaf Fragrance Oil and use the stick blender to mix in. Continue pulsing the stick blender, and using it to stir until there is no longer streaks of fragrance oil. Don’t worry about over stick blending, this recipe gives you plenty of time to work with it!
  4. Continue to stick blend until you reach a thin-medium trace. Pour the soap into the mold, and use a spoon or spatula to even out the top if necessary. Tap the mold on the counter to help get rid of any bubbles. Spritz the top with alcohol to help prevent soda ash. Cover the mold, and insulate the soap for 24 hours to help promote gel phase. Gel phase is not absolutely necessary, but it will help the soap unmold a little sooner! Once the mold can be pulled away from the sides of the soap with little resistance, carefully remove from the mold and cut into bars. With a 20% water discount, sodium lactate and gelling, I was able to unmold and cut this soap in 2 days. Without one, or all of these methods, this soap can take up to 2 weeks to remove from the mold, so be patient. =)
  5. Once the soap is cut into bars, use the Savon Soap Stamp to stamp the soap directly in the center. Check out this video for tips on stamping your soap. I found it was best to stamp these bars after right after unmolding. I also used the soap beveller to clean up the edges of these bars. Allow the bars to cure for 4-6 weeks, and enjoy!
Recipe by Soap Queen at