100% Olive Oil Soap: My Favourite Zero Waste Facial Soap Recipe

Hello zero wasters! Today we will make soap using again just 1 oil: olive oil!

100% olive oil is also called Castile soap has been produced for centuries

Olive oil produces a very low lather and is incredibly moisturising. This make this soap perfect for most skin types, and the perfect candidate for a facial soap!

olive oil castile soap zero waste facial soap recipe

Castile soap will need to be left in the mould to harden for a little longer than the normal 24-48 hours. This is because olive oil is a very soft oil that will cure in a hard soap over time, so we need to give it the time to harden.

If you are new to soap making, please ready through my blog post here and familiarise with the safety measures that you must adopt when making soap.

Want to watch it instead of reading it? Here is my Youtube tutorial:

100% Olive Oil Soap: The Perfect Facial Soap Recipe


200 grams / 7.05 ounce Olive Oil
38.61 grams/ 1.36 ounces water (40% discount)*
25.74 grams / 0.91 ounces lye

optional, but it helps the soap harden faster: half teaspoon of sodium lactate (usage rate is normally 1 teaspoon per pound/450 grams of oil)

Event though 100% olive oil soap is quite easy and fast to make, there are a few things we need to consider when formulating our recipe.

For this recipe, I have applied a 40% water discount and added sodium lactate to make the soap harden faster. These are both tricks you can apply once you know how to formulate your own recipes. You can read more about water discounts in my blog post here.

We also want to soap at higher temperatures, about 48 to 54 C/120-130 F degrees. When we are soaping at these temperatures, there is a higher chance that the soap will get through gel phase. When the soap goes through gel phase, the saponification process speeds up and the soap hardens faster. 

If you follow these tips you should be able to unmould the soap in about 3 days, otherwise you can leave it in the mould for up to 1 week.

48 to 54 C/120-130 F degrees

soap facial zero waste

 Interested in getting started with soap making? 



As always, we will wear our safety goggles and gloves to prepare our lye solution. Remember, always add the lye to the water and never the opposite! When the lye solution drops down to the desired temperature, add the sodium lactate and stir well before pouring the solution onto the oil.

If you follow these tips you should be able to unmould the soap in about 3 days, otherwise you can leave it in the mould for up to 1 week.

Our lye solution is then added to our oil making sure they are roughly at the same temperature (48 to 54 C/120-130 F degrees). It will take you slightly longer than usual to reach trace because olive oil is a slow-moving oil. Start stick blending until you reach light trace, and then add your essential oils (if any!).

olive soap facial soap zero waste

Once brought to light trace, I will add the essential oils – this is an optionall step, you can keep the soap unscented. I choose my favourite scents: lavender and grapefruit.

Olive oil soap zero waste

Stick blend until you reach a medium trace, then pour into the mould!

olive oil facial soap recipe zero waste

Cover the soap in a warm blanket or on a heating pad for the first 15-20 minutes after the unmoulding. This will force gel phase, speed up the saponification process and the soap will harden and unmould quicker. 

Once unmoulded leave to cure for at least 6 weeks, even up to 6 months before using it. The more you cure it for, the harder, milder and bubblier it will be.

Thank you so much for watching, I hope you enjoyed the recipe, and let me know: how would you scent this simple and super satisfying soap?

zero waste facial soap

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