The Science of Soapmaking

Ever tell your child, “Wash behind your ears…and use soap this time!”? Ever wonder why you need to use soap, I mean most of the dirt washes off with water, right?

Here at Twin Creeks Farm, we take a lot of pride in making our soaps. Each batch is like a science experiment, an art project and home economics all in one! You design the soap, measure out the right ingredients, mix them all up and magically they create something completely different than what you started with.  The only difference is, you usually have to wait a day or two for it all to happen, and then a month for it to cure. Imagine waiting that long for a cake!

Saponification is the chemical reaction that creates soap. This exothermic reaction is created by adding a fat or oil, to a base, which in this case is sodium hydroxide, also known as lye. During this process, the alkali (sodium hydroxide) divides the oils into fatty acids and glycerin. The sodium molecules then join with the fatty acids while the glycerin remains as a humectant, which draws moisture to the skin. This chemical reaction can reach temperatures of up to 200 degrees! While people often cringe at hearing the word “lye”, it is required to make soap, and proper safety precautions are taken to ensure there is no free lye left in the soap. Did you know lye is used in the production of many foods that you eat, like bagels, pretzels and many others! (But don’t try to use it at home!) To keep it really safe, there is an additional percentage of oils left unsaponified (meaning you use less lye than necessary) to create a mild and moisturizing soap. This additional leftover oil is called superfat. The entire process of these liquids coming together only takes a few minutes, then over the next day or so they will harden into a solid bar of soap. However, soap is best after it has cured for 4-6 weeks, when the complete crystalline structure of the soap has developed and the water that is added evaporates, allowing the bar to harden.

Most of the ingredients in soap making can be found at the grocery store. Some common oils used in soapmaking are olive, coconut, palm, castor, avocado, and cocoa butter. Each oil has its own unique properties. Some oils, like castor, create a lot of bubbles, while others, like coconut are very cleansing, but can be drying if too much is used. A great soap recipe takes all the properties of the oils into account, in proportions that allow for their unique attributes to enhance the bar of soap. A popular soap is castile soap, which is made with 100% olive oil, however, most modern soaps use a variety of oils and ingredients to create a wonderful bar of creamy, lathery soap. Colors, fragrances, essential oils, and even kitchen ingredients like oatmeal, salts and sugars can all be added to soap as well to enhance the appearance and scent.

But how does soap clean? It’s strange to thinks that oils will clean your skin and not leaving it feeling, well, oily! The molecular structure of soap after saponification leaves one end attracted to water (hydrophilic) and one end repelling water (hydrophobic). Basically, it loves the water on one side, and hates water on the other!  Because of this unique structure and the strong molecular bond, it can draw in the oils, grease, dirt, etc, break them down into smaller structures, and surround them with water. They can then be easily washed away. Because of it’s ability to decrease surface tension between water and another liquid, soap is known as a surfactant, which is the combination of three words, surface, active and agent.

So now that you know the science behind soap, make sure you use it! Soap treats germs and viruses just like dirt, it surrounds them and safely washes them away. The superfat helps the moisture in your skin to remain, while the dirt and germs get washed away. All in all, soap is a fantastic product, and it’s first use dates back to 2800 BC, so it’s been around for almost 5000 years! Watch the quick video below to see a batch of our Peppermint soap being made here at Twin Creeks Farm, start to finish! You can find all of our beautiful soaps on our website here – Twin Creeks Farm, and you can follow us on Facebook and Instagram, where we show videos, sneak peeks and lots of soap!