How I Make Lavender Castile Soap

Cold process lavender castile soap

Note: Since I retired, many people have asked for directions for making my soap. I’ve finally published the full recipe and directions for plain Castile soap here.


I made a new batch of Lavender Castile Soap this morning and thought that readers might be interested in seeing how cold process soap is made. A note: there are many so-called “castile” soaps advertised, but if it contains anything other than olive oil, water and lye, it isn’t true castile soap. The true castile soap’s only oil is olive oil – it’s named castile because originally it was made using the olive oil from the olive groves around Castile, Spain.

The first step is to mix the water and lye. I use pure rain water because it’s soft, which contributes to the soap’s sudsing ability. Many people are afraid of lye, but you can’t make soap without using lye. (See my post about “saponification” and how it relates to lye.) This mixture heats up significantly when first mixed, so you wait until it gets to the correct temperature (in this case, just under 100°F). While that’s happening, I slowly warm up the olive oil to the same temperature.

When both parts are equal in temperature, it’s time to mix the two:

making soap-1
The water/lye has just been poured into the olive oil & mixing begun

After you can see “trailings” (when the soap is thick enough that it leaves ‘trails’ when a bit is drizzled over the top), it’s time to add the lavender flowers & lavender & rosemary essential oils. I use a full five tablespoons of lavender essential oil and half that of rosemary for forty bars of soap, which is why it smells so amazing. Then I mix then thoroughly.

Making soap-2
Lavender flowers & the two essential oils are added
Making soap-3
Mixed & ready to pour

Then I pour the liquid soap into molds that hold eight bars each.

Making soap-5
Five molds = 40 bars of wonderful natural soap!

Finally, the soap is  tucked in to keep it warm and cozy, so it cools slowly. This takes about three days for this particular soap.

Making soap-6
All tucked in!

When the bars are quite solid, they’re popped out of the molds, cut & laid out on paper covered screens to cure for anywhere from two to three weeks, depending on the weather.

The result: pure, natural, and safe on the tenderest skin! Now available here in my shop.

Lavender Castile Soap
The final product – pure, natural and smelling sweet!

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