Hot Process Olive Oil Soap Recipe

Hot process olive oil soap recipe UK

March 29, 2023

Who doesn't love olive oil soap? It is traditional, natural and wonderfully gentle.

All you need is three ingredients, it doesn't get much more simple than that!

Hot process soap making can seem intimidating, but it is more forgiving than cold process soap making. 

Hot process bars of soap usually look a little rougher around the edges when compared to cold process soap. But when you're making super-natural recipes like olive oil soap this just adds to the rustic charm. Hot process soap can also be added to silicone moulds to help with the shape!

Hot process soap making safety

Don't be tempted to skip the gloves and goggles when you're making soap. Sodium hydroxide needs to be handled with caution.

Work in a well ventilated area when you're mixing the sodium hydroxide with water. 

Your soap will not be skin safe until a few days after you've made it, so wear gloves throughout the process.

Hot process soap can boil over if it gets too hot, so make sure that your olive oil is below 60C and your sodium hydroxide is below 30C before you mix them.


  • Gloves
  • Goggles
  • Weighing scales
  • 3.5 litre slow cooker
  • A 1200g soap mould, or homemade alternative
  • 2x 1L plastic jugs
  • Silicone or stainless steel mixing spoon
  • Digital thermometer

 Hot process olive oil soap ingredients



Sodium hydroxide solution mixture

1. Mix your sodium hydroxide solution

  • Put your gloves and goggles on
  • Weigh your sodium hydroxide
  • Weigh your water
  • Add your sodium hydroxide to your water (not the other way around)
  • Mix well until combined
  • Leave to cool until it is below 30C

Heating olive oil for hot process soap

2. Heat your olive oil

  • Turn your slow cooker on to high
  • Weigh your olive oil
  • Add it to your slow cooker
  • Heat until it is 50-60C

Hot process olive oil soap reaching trace

 3. Blend until trace

  • Turn your slow cooker down to low
  • Once your sodium hydroxide solution has cooled to below 30C, add it to the olive oil in the slow cooker.
  • Mix with a stick blender.
  • Blend until it reaches trace. This can take 5-10 minutes for olive oil soap.

Cook your olive oil hot process soap

4. Cook

  • Cook your soap without stirring for 30-60 minutes.
  • The soap will slowly start to look like mashed potato with a glossy sheen to it.
  • It will then become more translucent, like Vaseline. That means it is done! 
  • Remove the pot from your slow cooker
  • Stir it, but try not to mix any of the crispy edges mixed in to the soap.
  • Allow to cool until your soap is below 80C.

Olive oil hot process soap moulded

5. Mould your soap

  • Scoop your soap into your mould
  • Tap it on the work surface to try and eliminate air bubbles
  • Smooth and level the surface
  • It will usually look a little rough, but it will create a very natural looking soap.
  • Leave it for 24-48 hours before unmoulding and cutting

Cutting olive hot process soap

6. Cut and cure

  • Unmould your soap
  • Cut your soap into bars
  • Arrange your soap bars with space for air to flow between them
  • Leave your bars to cure for 2-3 months

 Olive oil hot process soap bars

Continue learning

Now you've learned how to make hot process olive oil soap, why not continue your soap making journey?

How did your olive oil soap come out? Comment below and let us know!

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