What is lye?

Can soap be made without it?

Why is lye not on my soap label?

Those of you who know me through my soap making courses whether that be online or in person will know I love a good science lesson! It is not that I am a science geek but I do feel it is really helpful to have a bit of an understanding of why you are doing something and I like to think it is not too boring!

Firstly - what is lye? 

The proper name for it is sodium hydroxide, chemical symbol is NaOH and it is also known as caustic soda.

I will just answer a few questions you may have first. Yes it is caustic, yes it is the stuff they use in the movies to dissolve bones to cover up a murder, yes it is drain cleaner and yes it can do you some serious harm. It is derived from salt water which you could probably deduce from the Sodium aspect in the name and through electrolysis so I guess you can call it a natural product in some way.

It comes in bead or grain form and can be obtained from either specialist soap making stores or alternatively, many hardware stores will also sell it. In the drain cleaner section!

You may find the carriage costs for purchasing lye online are high. This is because it is classed as Dangerous Goods and only certain couriers are authorised to carry it.

Can soap be made without lye?

In a nutshell no. It is the chemical reaction between water, sodium hydroxide and the fatty acids found in butters and oils that forms soap crystals. If you would like to know a little more about how that all works I have a whole blog on the subject here.

What about melt and pour soap? Many people start with this for the very reason that they do not have to mess around with lye and I totally get that, but melt and pour is still soap and was originally created with lye - however as that aspect has already been done for you it is easy to use and perfect for all ages.

What about bars that claim to be 'soap free' ? These are created from synthetic detergents and whilst they may look like a bar of soap they are not technically soap, in the true sense of the word. They are also known as syndet bars.

To summarise, you can have a lye free product that is similar to a bar of soap but you cannot make real 'soap' in its true form without lye.

Why is lye not on my soap label?

The simple answer is because there is no lye or NaOH in your soap once it has become soap. The Na (sodium) O (oxygen) and H (hydrogen) all react with the other ingredients to form soap salts.

From a labelling perspective, it is worth mentioning here that soap is classed as a cosmetic and therefore has to abide by the same legislation. Here in the UK (and EU) that means it must either have a label with certain information on (including in the ingredients), or that information must clearly be displayed at the point of sale.

The soap label has a specific format it must follow and example of which is below.

The names of the butters and oils have to reflect the saponification process so your soap may well have olive oil and sodium hydroxide in at the beginning but by the end that is now Sodium Olivate hence this is on the label.

As a point of interest Sodium Cocoate is Coconut Oil  and Sodium Cocoa Butterate is Cocoa Butter.

It is really helpful to have an understanding of these terms as you will find it easier to know exactly what you are buying in a shop. If your soap bar has no labelling, either at the point of sale or on the bar itself steer well clear, this means they are not adhering to the very stringent cosmetics regulations and it is highly unlikely that the soap will be cosmetically assessed either or have any of the other required documentation in place.

On that note, no such assessments exist for dog or horse soap which personally I feel is not ideal. It would be so much easier to have a formal structure in place for pet shampoos etc but it is an area which is missed. They do not have to follow the same legislation for labelling and in fact come under CLP regulations which is a whole different topic that I will cover in the future.

If making soap from scratch is on your wish list check out all the online and in person learning options available to you here.