The answer is, you can't.
As this would be a very short post with just that statement, I will explain.
What is Lye (Sodium Hydroxide)?
Sodium hydroxide, also known as caustic soda, or lye, is an inorganic compound with the chemical formula NaOH. It is a white solid and highly caustic metallic base and alkali salt which is available in pellets, flakes, granules, and as prepared solutions at a number of different concentrations
Sodium hydroxide is used in many industries, mostly as a strong chemical base in the manufacture of pulp and paper, textiles, drinking water, soaps and detergents and as a drain cleaner.
Many people seem to look at Sodium Hydroxide as the dangerous element within soap. The thing is, when you use soap, there is no Lye in it at all, it is just used in the process of making soap.
What is Lye used for?
- Food uses of sodium hydroxide include washing or chemical peeling of fruits and vegetables, chocolate and cocoa processing, caramel coloring production, poultry scalding, soft drink processing, and thickening ice cream. Olives are often soaked in sodium hydroxide for softening; Pretzels and German lye rolls are glazed with a sodium hydroxide solution before baking to make them crisp.
- Sodium hydroxide is used in some relaxers to straighten hair
- Sodium hydroxide is used in the home as a type of drain opener to unblock clogged drains, usually in the form of a dry crystal or as a thick liquid gel
- Most yellow coloured Chinese noodles are made with lye-water but are commonly mistaken for containing egg.
- Some methods of preparing olives involve subjecting them to a lye-based brine
- Sodium hydroxide is also the chemical that causes gelling of egg whites in the production of Century eggs.
- Last but not least, Sodium hydroxide is traditionally used in soap making (cold process soap, saponification).
Handmade soap from the cold process also differs from industrially made soap in that an excess of fat is used, beyond that needed to consume the alkali (in a cold-pour process, this excess fat is called “super-fatting”), and the glycerine left in acts as a moisturising agent. However, the glycerine also makes the soap softer and less resistant to becoming “mushy” if left wet. Since it is better to add too much oil and have left-over fat, than to add too much lye and have left-over lye, soap produced from the hot process also contains left-over glycerine and its concomitant pros and cons.
But my friend makes soap without Lye!
They will of course be using a melt and pour kit which is basically rebatching soap that has already been made using Lye. Great for those who want to play at making soap, but at the end of the day, they are not really making soap, but remoulding it and adding their own personal touches. Great for those that do not want to take the risk of handling Lye which certainly can be dangerous.
A basic cold process soap recipe
Olive oil (26.5 ounces)
Coconut oil (16.5 ounces)
Palm oil (10 ounces)
Lye (209 grams)
Your choice of essential oils (2.7 ounces - optional scent)
Distilled water (20 ounces)
In conclusion. So why are some people concerned about Lye being used in the production of soap?
I could be that the idea of using drain cleaner in the soap making process seems dangerous. However, the danger is in the making, not the using. We can see above that Lye is used in food processes, so why all the worry? In days past, homemakers made soap using lye made from wood ash. Sophisticated scales for measuring were not available and often too much lye was used. When saponification occurred, some lye was left in the soap, making it harsh on the skin. It is vitally important to measure carefully so that the correct amount of lye is used.
So, soap is made using Lye, but Lye is not present in the soap when you buy and use it, just like it is not in the foods that use Lye in their preparation.