Soap Science 101 – Making Handmade Soap

How handmade soap is made – the process.

All soap is made with a chemical process called, Saponification.

Simply put, a liquid mixture containing sodium hydroxide (a.k.a. lye) is mixed with choice oils/fats/butters. It then goes through the chemical process called saponification. Mixed in the correct proportions and all of the lye mixture molecules and all of the oil/fat molecules pair up, leaving no extra lye molecules. Once the process has completed, the end result is soap.

No soap can be made without the use of sodium hydroxide. If sodium hydroxide was never an ingredient, it is a detergent bar, or similar – this is what you’ll typically find on the grocery shelf.

Unlike our great ancestors, who made soap using ash and fats over an open fire, we are able to use recipes and scales which measure our ingredients exactly – thus, done properly, result in soap that will not ‘burn the hide right off ya’.

Make your own handmade soap using our tutorial: Instructions for Making Crock Pot Handmade Soap.


  1. I love your articles on handmade soap, they are to the point and interesting! Keep up the good work – definatly subscribing to you RSS!!

  2. Do you have any good links for making shampoo or liquid soap making with potassium hydroxide? I’ve done it but I’m unsatisfied with my recipe and I always have good luck with your recipes. :-)

    My daughter and husband are horribly allergic to sodium laureate so I have been making their shampoo. My husband had thought all these years that he was just prone to dandruff – but when he switched to a non-sodium laureate based shampoo the flakes went away immediately.


  3. Hi Judy,
    I’ve been studying up on how to make hot process soap in a crock pot and think I’m about ready. I really want to make rosemary mint soap for our sauna and cabin and your recipe sounds great. However, I’m confused by the percentage numbers after the listed ingredients in the recipe. Could you please tell me what they’re for? Thanks for your help.

    • Hi Tina – That’s an awesome question!

      First, you’ll notice, if you add it all up, that it comes up to over 100%. Hrmm.. why’s that you ask? Well, head over the the post with links to soap recipe calculators. You *always-always-always* want to run your recipe through a calculator, regardless! (One nice thing is that it makes it super easy to resize your recipe to fit what You want to make) Most importantly to ensure your recipe will have enough oils to lye-mixture ratio — definitely don’t want your recipe to lye heavy.. that’s what happened when our ancestors made soap without calculators.. you might end up with some seriously strong soap that would / could burn, or if nothing else, be extremely harsh and drying to your skin. So, you want your main oils to add up to 100%.. plus a little extra. The main is typically around 5 or 6 “super fat” – this is the extra oils that give your soap it’s moisturizing abilities. šŸ˜‰

      So.. if you take what I always try to tell people… a recipe is just a guideline.. it’s not a strict rule you must follow.. play with it some. you’ll see I use *about* 60% olive oil, *about* 20% palm kernel oil and *about* 20% palm oil. 1) I give the recipe in percentages because when you run it through a calculator for a 1 pound batch or a 6 pound batch, the percentages stay the same.. and 2) I say *about* so you know you can be flexible.. of course, in my actual recipe I didn’t say *about*, but you’ll see the percentages aren’t exact.

      Rosemary Mint soap is a favorite – with most people.. and my recipe is easy, and feels really nice. I hope you give it a try – the crockpot for soap making is awesome! And let me know how it turns out!

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