Updated: Feb 10, 2022
“How do you make your soap?” is a question I’m often asked, and like anyone who
loves what they do I can talk about it for hours. And I know I’m not alone in this,
because it’s a hot topic in every soap maker’s group I’m in. Soap making has rules,
but it is also infinitely flexible, and the ‘how’ of soap making definitely depends on
who’s doing it, bar a little bit of science.
All soap – commercial and handmade – is made with, essentially, just two
ingredients: an acid and a base. The chemical reaction that occurs when these are
mixed is call saponification, and results in soap and glycerine.
At home, lye (or sodium hydroxide) is used as the base. It is extremely caustic and
requires care to work with – all soap makers use safety equipment, including gloves
and eye masks, to protect themselves from splashes, and as even the fumes from
the reaction can ‘burn’ your nose and throat, ventilation is a key requirement for any
The lye is completely transformed during the saponification process, so there is none
of it left in the final soap bars, making them safe to use.
The acids needed for the process come from the fatty acids in animal fats or plant
oils. Fatty acids determine the properties of the fats and oils, and so also the
properties of the finished product. For example, saturated fatty acids, tend to be solid
at room temperature and are called ‘fats’ (like coconut oil and palm oil). They are
high in the specific acids which contribute hardness, lather and cleansing properties
to a bar of soap. Olive oil, on the other hand, is liquid at room temperature and high
in unsaturated fatty acids. These types of oils make a softer, more nourishing bar.
What about the glycerine? Glycerine is natural humectant, meaning that it holds
moisture near the skin, and is found in all homemade soap. During saponification, it
is separated from the oils and settles between the soap molecules, where it acts to
nourish and soften the skin.
So, to make a bar of soap you need a recipe that includes, at least a base (lye) and
an acid (fats and oils), but also water, or something to dissolve the lye in, and things
to make it pretty. And that’s where it starts to get exciting.
We already know that there are a variety of fatty acids, and that they all have
different properties, and add different elements to the finished soap. How then do
you formulate a recipe for soap? You think about what you want your soap to be like,
and you get to know your ingredients.
Making soap is fun, but it requires preparation and practice. Knowing the science
behind the process can help with making decisions about what, and how, to use
different ingredients to get the most out of your finished products.
What makes the perfect bar of soap ultimately depends on the user – for me, the
perfect bar of soap is one that lathers in our hard water and doesn’t leave the skin on
my face feeling dry. And I think I’ve got it pretty close!
What’s your perfect bar of soap? Why don’t you try a Shepherds Cottage bar today
and see if it fits the bill?