I love making my own soap. It's not difficult to make once you understand the basics. Soap is made by combining fats and oils with lye (sodium hydroxide). Soap is created as lye reacts with the fats and oils in a chemical process known as saponification.
Another reason I like to make my own soap is I am grossed out by what is in a regular bar soap. Ivory soap ingredients: Sodium tallowate, sodium cocoate or sodium palm kernelate, water, sodium chloride, sodium silicate, magnesium sulfate, and fragrance. The main ingredient is rendered beef fat. Ewwww! When I make soap, I prefer to use vegetable and non-animal oils.
This batch was for a Spa Bar or Salt Bar.
Goggles & rubber gloves (wear a long-sleeved shirt)
bowls or measuring cups for mixing (glass pyrex, or plastic)
stainless steal or silicone spoon or spatulas
bowls to weigh out salt, colorant, fragrance
Lined mold (I like to use a wooded soap mold lined with butchers paper)
10% Palm Kernel Oil (creates a hard bar of soap, lathers well)
80% Coconut Oil (creates a nice, hard bar of soap, fluffy lather)
5% Avocado Oil (contains Vit A, D, E, and helps in healing, conditioning, moisturizing)
5% Castor Oil (moisturizer, humectant, rich conditioning lather)
Lye (Sodium Hydroxide)
Fragrance or Essential oil (optional)
Sea salt (fine grain)
Mostly coconut oil is used because it is the only oil that will produce a lathering soap in salt water. It doesn't really matter what oils you use as long as you use at least 50% coconut oil. Normally you would not use this much coconut oil in a soap recipe or the soap would be drying, but that doesn't seem to apply when making spa bars. Sea salt is a natural rejuvenating & healing element. It contains anti-inflammatory properties making it ideal for damaged & irritated skins. The salt bar will cleanse the pores helping excrete the daily toxins & pollutants the skin is exposed to. It has a very rich lather and a creamy texture, not at all scratchy, and I do not find it to be drying at all.
I run all my soap recipes through a lye calculator to figure out the correct measurements. The saponification index measures how much lye is required to turn that oil into soap. Different amounts of lye are needed depending on the saponification index of the oils used to make the soap. I use http://www.soapcalc.com/.
Once you have your recipe (there are tons out there on the internet), the first step is prepare your work area. I put down several layers of newspaper and clear away everything else. Put on your protective gear. Lye is VERY caustic and can easily burn your skin. Noxious fumes are also released from the exothermic reaction that occurs when you mix the sodium hydroxide with water so either wear a face mask, or do this by an open window and leave the area right after mixing the sodium hydroxide with the water. You must have all of your equipment and ingredients prepared before you start since the reaction moves quickly.
Preheat your kitchen oven to its lowest temperature (approximately 170°F).
Weigh out the distilled water first and put it in a heat resistant container (glass, stainless steel or enamel). I use Pyrex. Next weigh out the sodium hydroxide. Add the sodium hydroxide to the water and mix with your spoon or spatula until dissolved. Never add water to the sodium hydroxide as this can cause a volcanic like reaction (snow falls on water is how I remember which order to mix them). Leave this solution to cool for about 1 hour. This really stinks so either do it outside or by an open window. I do this in my stainless steel sink which is right below a window. I do not worry so much about temperatures, but I like to have both my lye solution and oils cool enough so that I can touch the bottom of the containers they are in without it being too hot to hold my hand there for some time.
While the lye is cooling, weigh out your oils, fragrance, colorant, and salt. Mix your colorant into the fragrance if the color is a powder or if it is liquid you can mix it into your salts.
Melt your oils in a microwave heating in increments of 30 seconds until all the coconut oil is just melted. You do not want it to get too hot. Again check to make sure you can touch the bottom of the oil container without it being too hot to hold your hand there.
Once both the lye and oils have cooled sufficiently you can add the lye solution to your oils.
Begin to stick blend for about 30 seconds or so and then stir with the stick blender. This helps to keep the motor in the stick blender from burning out. Keep the stick blender fully submerged to decrease the amount of air that gets mixed in and reduce the number of bubbles formed.
You will see the mixture start to thicken and turn more of a creamy opaque color after a couple of minutes. Once the mixture is at a light trace add your fragrance and coloring. Trace is characterized by lines or drops remaining on the surface of the soap when you remove the stick blender.
Continue to stick blend until you reach a medium-thick trace.
After mixing in all the colorant, mix in the sea salt. I use a 1:1 ratio of sea salt to oils. You can use slightly more or less depending on your preferences. Do not use Dead Sea salt as the extra minerals seem to cause undesirable excess sweating of the bars.
Pour your soap in a lined mold.
Cover the top of the soap with a layer of plastic wrap to help prevent ash.
Place the mold into your preheated oven and turn off the oven. Leave the soap in the oven for about 2 hours or until the soap feels firm enough to cut. I put it on a cookie sheet, because I've had it overflow and ooze all over the oven, which was a huge mess. Cut the soap immediately after you take it out of the oven or else it will become too hard to cut.
Here are some sources I've used to get my ingredients to make soap: http://www.mountainroseherbs.com/ (my favorite)
http://www.millersoap.com/ (tons of very useful information)