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Castile Soap Recipe

Castile soap (only olive oil ) Very simple recipe, but you can play around with it in many different ways.

Lye 208 g

Water 483 g

Olive oil 1588 g

Essential oil about 60 drops

All tools should be safe for use with lye:

1. Something to pour the soap into such as molds or a box , spoons, bowls, pans, mask, gloves, goggles, vinegar, rubber spatula. This is natural soap, so you can use pans etc from your kitchen, but I prefer to have separate pans that I only use for soap.

2. Have two stainless steel pans with lids ready. One for the oil. One for the water with Lye mixture.

Step 1: Lye. Make sure to do this outside or somewhere with air flow. Also make sure no one will touch it, such as children. It gets very hot. Add the water to the first pan. Measure the Lye and slowly, while stirring ,carefully add the Lye to the water a little at a time. Do not do it the other way. Only add lye to the water. Use gloves , mask and goggles if you'd like. (If any splashes onto you, use the vinegar where it burns on your skin . It neutralizes the lye.) Once the lye is all dissolved in the water, let it sit in the pan with the top just a little open to let out some heat. Make sure it is sitting on something that can handle heat. The pot will get very hot. I usually leave it on a large rock outside so that there is airflow around and under the pan to cool it down. Let it cool to room temp. Takes at least 30 minutes or more. You can speed this up by placing the pan in a water bath in the sink, but I prefer to just wait. You can use thermometers for all of this, but I just feel the outside and bottom of the pans to know.

Step 2 : Oil. While that is cooling, measure the oil and add it to the other pan. (Because it is only olive oil it is already melted, but if you ever want to add other oils, make sure to melt them together and return to room temp). You can speed this up by placing the pan in a water bath in the sink, but I prefer to just wait.

Step 3: Mix. Once both pans are at room temp, you slowly and carefully add the Lye mixture to the oil. Not the other way around. Once it is mixed with a spoon, you can continue to mix with a spoon or use a stick blender until a "trace" is formed. This is when you can see the trail of the soap as it falls from the spoon. It leaves a trace. Add essential oil, or powdered herbs, if desired at this point.

Step 4. Pour into molds quickly . Scrape the pan to remove all of the soap. Let it sit 24 hours then remove from the molds. It must cure in open air. I use screens or trays and put them somewhere where they won't be bothered, such as on top of the fridge . Flip them every once in a while over the next few months to allow them to cure evenly. After 1 year they are ready to use. They are safe to use immediately, but they won't be hard, so they would melt in the shower . Let them harden for a year.


1. Important to let the Lye and oil get to room temp. If it is even a little hot, it will harden too quickly while you are mixing and you won't be able to get the soap into the molds .

2. What I like to do, is infuse herbs into the oil ( and or the water) before I use it for soap. So I would put some (example) nettle, henna, mint, cinnamon, oats, geranium flowers, lemon peel, lavendar , lemongrass, flax, etc. ( can be fresh or dried herbs) Into the oil in a jar and let it sit in the sun for at least a month ( or heated slowly over the stove for an hour) . Then I use the oil for soap .

3. Also the water portion can be made into a strong tea of any of these or other herbs and then mixed with the Lye. These extra steps just make for interesting and extra nourishing soap. But they aren't necessary.

4. Important to note: You slowly and carefully add the lye to the water, not the other way around. Then add the lye/water mixture to the oil, not the other way around. Pouring anything into lye can cause an explosion that can splash onto you. Very dangerous if done the wrong way.

To wash the pans , spoons etc, pour vinegar on them or let them sit in the pan in vinegar before washing to neutralize the lye. You are washing soap, so it's self cleaning.

Ps. Soap can be made using wood ash instead of lye, but that's another lesson for another time. For more information on this technique see my related links on my page

If you have any questions, please ask.


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