Traditional Castile Soap Recipe

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Learn how to make a simple 100% olive oil, traditional Castile soap recipe that’s scented with natural essential oils.

This traditional Castile soap recipe is made using 100% olive oil and is scented with natural basil, lemongrass and rosemary essential oils.

This traditional Castile soap recipe is scented for spring with natural basil, lemongrass and rosemary essential oils. Unlike my Castile soap recipe with bee pollen powder I shared recently, this traditional Castile soap recipe is made using 100% olive oil. However, as 100% olive oil soaps tend to be a softer soap that takes months to harden, I added a small amount of sodium lactate to this traditional Castile soap recipe. I also used a steeper water discount than normal. This allows you to unmold this Castile soap after a day and cut it into bars within 24-48 hours. You can, however, omit the sodium lactate. Just keep in mind it may take a bit longer to harden up.

This traditional Castile soap recipe is made using 100% olive oil and is scented with natural basil, lemongrass and rosemary essential oils.

Traditional Castile Soap Recipe

© Rebecca D. Dillon


36 oz. pomace olive oil

4.5 oz. lye/sodium hydroxide
11 fluid oz. distilled water

.5 oz. sodium lactate (60% solution)
.35 oz. basil essential oil
.35 oz. rosemary essential oil
.35 oz. lemongrass essential oil

Soap Notes:

water as % of oils = 30.5%
6% superfat
+/- .5 oz. essential oil per pound of oils

This cold process Castile soap recipe yields 10-12 bars of soap that will weigh around 4 oz. each depending on how they are cut and fits inside my DIY wooden loaf soap mold.


You’ll need to follow my basic cold process soapmaking instructions for this traditional Castile soap recipe. You can substitute virgin olive oil for the pomace olive, however keep in mind it’s likely to take longer to reach trace.

(If you’ve never made cold process soap before here’s another good, inexpensive beginner’s cold process soap recipe.) Be sure to take all proper safety precautions when working with lye including goggles and gloves.

Begin by measuring out the distilled water in fluid ounces. Pour into a heat safe pitcher. Next, using a digital scale weigh out the lye. Slowly pour the lye into the water in a well ventilated area and stir until all the lye has dissolved. Set aside to cool.

Now weigh out the olive oil using a digital scale and combine in a stainless steel pot. Heat to about 90°-95°F then remove from heat. Prepare you essential oils by weighing them out into a glass Pyrex measuring cup and set aside.

When the lye-water has cooled to around 90°-95°F – you want the olive oil and lye-water to be about the same temperature – you’re ready to make soap.

Weigh out the sodium lactate and stir into the cooled lye-water. Now slowly pour the lye-water into the olive oil. Mix with a stick blender until you reach a light trace. Add the essential oils and combine with the stick blender until you reach a full trace.

Pour the soap into your prepared mold.

Level the top of the poured soap with needed. Leave uncovered so the soap doesn’t overheat. Set aside for 24 hours.

After 24 hours your can unmold your Castile soap loaf. If it’s hard enough, cut it into bars when you unmold it. If it’s still a bit soft, wait an additional day then cut into bars. Allow bars to cure anywhere from 4 weeks to 6 months before use. The longer the cure the better the bar. Typically soaps created using a traditional Castile soap recipe are cured for 4 to 6 months for best results.

This traditional Castile soap recipe is made using 100% olive oil and is scented with natural basil, lemongrass and rosemary essential oils.

Once your Castile soaps have cured, wrap and label as desired. I added butterfly stickers to mine and simply printed them onto blank sticker paper.

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About Rebecca D. Dillon

Rebecca D. Dillon is a soapmaker, DIY-er and blogger whose life is controlled daily by a dachshund. You can learn more about Rebecca by checking out her bio. Or discover more great skin care & beauty recipes by subscribing to Soap Deli News blog via email.


  1. I only have powdered sodium lactate. What ratio should I combine it with water to create a liquid SL? Unsure how to use powdered version in soap making :((
    Please help anyone.

  2. Glad i read this. I just made a batch of soap that was about 80pc olive oil and was worried about how long i should let it cure. now i know! Thanks for sharing…

  3. Very good recipe. thanks.

  4. The butterflies on top are such a good idea. Perfect for the spring =)

  5. Hi can u explain the difference between regular olive oil and olive oil pomace? I know one is less expensive but I’m more curious to know what the difference will be in my finished soaps depending on which oil I use.its confusing because I have some recipes that call for 100% pure olive oil and some that say to use the olive oil pomace. Are they interchangeable?

    • They aren’t really much different as far as soapmaking is concerned and pretty much perform the same way. You can use either or however pomace does trend to trace a bit faster.