• By Just a Soap

    Sodium Hydroxide (Lye-Caustic Soda)

    Sodium Hydroxide, often referred to as Lye or Caustic Soda is one of the core ingredients used for cold process soap making.

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    Sodium Hydroixde aka Lye aka Caustic Soda is a core ingredient of any soap bar. You can't make soap from scratch without Sodium Hydroxide - it's a simple fact.  

    It's the chemical reaction between the sodium hydroxide and the fats/oils that produces the soap.  A little bit of magic really.  (In melt and pour soaps, this process has already been carried out before the soap base reaches you).

    If you are looking to make soap from scratch, and therefore become a soap magician, then Sodium Hydroxide is a must.  As part of the saponification process, and by this we mean soapmaking, all the Sodium Hydroxide is used up when it converts the fats and oils to soap.  

    That's why you will never see Sodium Hydroxide listed as an ingredient - because after the end process it isn't there any more.  Another part of the magical process.


    • this is 99% pure and so is perfect for soap making.  Unlike drain cleaners, there are no extra additives or perfumes.
    • it's in a granular form supplied in the manufacturer's plastic container with tamper proof lid so it is easy to pour and store.
    • we buy direct from the manufacturer so we know it's a pure product
    • is caustic soda the same as lye?  yes it is.

     Recommended for

    • making cold process soaps.

    Important points to remember

    • When you are using it for Cold Process soap making,  remember to always add the Sodium Hydroxide to the water and never the other way round.  It is often mentioned to not use hard water for Cold Process soap making and so why not consider using Distilled Water which is readily available in DIY shops or Car Spares Shops.
    • We recommend that you take appropriate safety precautions (including rubber gloves and safety goggles) when using this product as it can cause chemical burns.  It should not be used with children.  Please don't let this scare you - just treat the product with the necessary amount of common sense.  
    • We have chosen to send our own Safety Sheet with this product so look for it in the box and take a read before you start.

    Please note we are UNABLE to ship this product Internationally (as in outside of the UK).  

    Please note we are UNABLE to ship this product via the ROYAL MAIL so please do not select this shipping option.

    Delivery Information

    We ship parcels and pallets to all of the UK

    Technical Info

    Find the MSDS information and technical data here

    Have a question?

    Take a look at the FAQ to see if we can answer your question