Basic Cold Process Soap


450g coconut oil

450g olive oil

133g of lye (Sodium Hydroxide)

297g water

Up to 10g of essential oils of choice (optional)


A slow-cooker or a non- aluminium bowl for heating the oils

A digital scale

A stick blender 

A wooden or metal spoon

A spatula

Soap moulds (or an old cardboard box lined with parchment paper)

Gloves and sunglasses or eyewear

A large bottle of white vinegar for neutralizing the lye mixture if it spills on anything.


Note: Make sure that your work area is clean, ventilated and that there are no children nearby. This is not a good recipe to let children help with since Lye is caustic until mixed with water and oils. It is best to have all your ingredients and materials ready before you begin, so you can just mix everything quickly and easily. 

  1. Start by melting your coconut oil. You can do this in the microwave or in a pan. 

  2. Carefully measure the lye and water separately. 

  3. Pour the water into a bowl or large glass jar. With gloves and eye protection, slowly add the lye to the water. NEVER ADD THE WATER TO THE LYE (this is really important). Stir carefully with a spoon, making sure not to let the liquid come in contact with your body directly.

  4. As you stir, this will create a cloudy white mixture that gets really hot. Let this mixture set for about 10 minutes to cool. It should become clear and not cloudy when it has cooled.

  5. When you have your melted coconut oil, pour it into a bowl and add the olive oil. 

  6. Slowly pour in the water and lye mixture and stir.

  7. Quickly rinse the container used for the water and lye mixture out in the sink. I rinse well and then re-rinse with white vinegar to make sure all Lye has been neutralized.

  8. Use the metal or wooden spoon to stir the lye/water mixture into the oil mixture in. 

  9. Once it is evenly mixed, use the immersion blender to blend for about 4-5 minutes or until it is opaque and starting to thicken.

  10. If you are going to use essential oils for scent, add them now. 

  11. Quickly and carefully spoon into moulds. Any container will work, but I like loaf tins lined with parchment paper. I have included instructions for making one out of a box lined with parchment paper.

  12. Cover the moulds with parchment paper and set in a cool, dry place, away from kids and pets.

  13. After 24 hours, using gloves remove the soap from the moulds and cut into bars. 

  14. Leave the bars somewhere to cure for about 4 weeks.  You can test if they are done by sticking your tongue on them (yes this is really what you do) to see if the lye is still active.  It will zing you like a battery if they aren’t ready.

Kat GoldinComment