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.