safety instructions

Soapmaking requires the mixing of sodium hydroxide (NaOH), commonly known as caustic soda, in water to produce a lye solution.

Caustic soda usually comes in two forms; pearl, which has the appearance of sugar like beads, and flakes, which are similar in appearance to Lux soap flakes, but smaller.

 There are two important facts to note about caustic soda:


  • caustic soda is very strong alkali and can cause severe burns;
  • when mixed with water it releases heat causing the mixture to heat up to 80°C or more.

When dry, caustic soda is fairly benign. However, once dissolved in water, it becomes very alkaline or 'caustic'. The moisture on your skin is sometimes enough to cause a single bead or flake of caustic soda to dissolve and result in a small burn.

For this reason it is important to wear covered shoes, long pants, rubber gloves and safety glasses.

add sodium hydroxide to the water
add sodium hydroxide to the water

mixing with water

When mixing caustic soda with water it is absolutely essential to add the caustic soda to the water and not the other way around. Pouring water into a container of caustic soda could cause the water to suddenly become steam resulting in small explosions and splashing.


Keep caustic soda dry in a sealed, properly labelled container, out of reach of children.

Store lye in a sealed plastic container. When allowing lye mixture to cool, place sealed container in a safe place (away from children and pets) and label to ensure it is not mistaken by others.

cleanup of spillages

Spillages of dry caustic soda are best swept up and disposed of properly. Add a cup of vinegar to half a bucket of water and mop area thoroughly.

For spillages of lye, mop up and rinse the area with vinegar and water as above. Rinse thoroughly all brooms, mops, dustpans afterwards.