What is a Lye Calculator and Why Do I Need One?

There is a little science that everybody needs to know when they start on their soap making journey but although it sounds a little intimidating it really is not and you definitely do not need to been science minded at all. 

When natural butters and oils are mixed with NaOH (aka lye or caustic soda) and water a process called saponification occurs and those 3 basic ingredients are converted into soap! Yes, that really is all soap is! Bizarrely oils can be turned into a product which then breaks down and washes oils off! I love the idea we can use the power of plants that grow on our planet to keep ourselves clean and healthy.

Different oils and butters require different quantities of NaOH to turn them in to soap - it is essential that the correct quantity is used or your soap may be lye heavy and dangerous to use or have too many free floating oils which may cause it to be too soft or become rancid.  You do need a little understanding of this process to ensure you only make soap that is safe to use.

To begin with, it is always easiest to find a tried and tested recipe to make - there are plenty of options on the internet and I have included a basic human and dog soap recipe below -  but once you are confident to try and formulate your own recipes it is essential that you run the figures through a lye calculator. My favourite ishttp://soapcalc.net/calc/soapcalcwp.asp

Use it every time you try a new recipe - even if you copy one from a book or the internet - there is always the possibility of a misprint and you do not want a failed batch of soap or worse, caustic soap. If you swap an oil for another in a recipe you must recalculate it as it will almost certainly have a different saponification value. It looks a little complicated but you can find a short video showing you exactly how to use the soap calc version here

If you are interested in learning how to make your own soap then you can find out more about my hands on workshops and online learning options here