This weekend we made our first attempt at making homemade soap. It was pretty straightforward and a lot easier than we had anticipated. There was some leftover olive oil from 2011 in the bottom of the stainless steel containers we use to keep it. We needed to remove it to refill them with the new 2013 olive oil. The leftover olive oil had gotten cloudy and thick and although we didn't want to use for cooking we couldn't just throw it away.
So we looked up some online recipes and found a great DIY video of how to make olive oil soap.
We followed the recipe adjusting the dosages and confirmed the lye proportions using an online lye calculator (inputing 0% superfat and 0% lye discount). The only ingredients you really need to make oilve oil soap are lye and olive oil. Lye is produced by mixing together granulated sodium hydroxide (also known as caustic soda - available in any hardware store) and water and is very corrosive. You need to wear protective gear (gloves and protective glasses) to prevent chemical burns from splashes.
We had 1773g olive oil, so according to our calculations we needed 237g caustic soda and 663g water to make the lye. We weighted the olive oil first to be able to make just the lye we needed - you don't want to store leftover lye...
We used only plastic and silicone containers and tools because lye can damage glass and wood and react vigorously with some metals (like aluminium) to produce highly flammable hydrogen gas.
Then we weighed the caustic soda and water and added the caustic soda to the water (never add water to caustic soda!).
Mixed it well until it became fully dissolved and transparent. Making lye is an exothermic reaction and it really heats up! We did it outdoors because of the fumes that are released during the dissolution.
Gently poured the lye into the olive oil.
Gave it a mix with a plastic spoon.
And then used a hand blender to speed up the process of getting the soap to trace. Trace is a sign of emulsification, meaning that the oil and water are completely mixed together and are not going to separate again. It is called trace because when you drizzle a little of the mixture back into the container, you see a little ridge or trace of it left behind that takes a few seconds to disappear. Before hand blenders were available, it took 3-4 hours to thoroughly mix the ingredients; now it takes 2-3 minutes. We used an old blender since we wouldn't trust it inside a soup pan again.
We replaced the essential oils and dye with some fresh lemon verbena (Aloysia citrodora) that we shredded into the mixture with the hand blender.
Poured the mixture into two IKEA silicone backing molds to make it easier to unmould. You can also pour it into molds that will make individual soap bars.
And finally covered the molds with a chopping board and towels to keep it warm during the saponification process. Most recipes say you can cut your soap in slices after 24 hours but we will leave it a few days longer. It will then need to cure for about four weeks to be ready to use. We'll update this post after our first bath with homemade soap! Let's hope it's as good as the 8$ version.