This is a small batch "blender recipe" that will give you 5-6 bars of castile soap. I have made this several times and it has never failed me. Credit for this recipe must be given to Phill at city mouse country house. The directions are copied and pasted from the original from Phill who says this is a recipe he developed by learning from friends like Peggy at Hidden Haven Homestead.
Lye is the active ingredient in home made soap making unless you are using the melt and pour recipes or kits. Lye is a caustic chemical so it must be properly handled. Don't be afraid, but be safe and take precautions such as wearing latex gloves and avoiding the fumes.
Castile soap is Olive Oil soap. Some say the blender and the containers that you use to make the soap should not ever be used for anything else. I tend to disagree here as it’s just soap. Safety goggles are a good idea too. Do not allow lye to come into contact with anything because it corrodes. DO NOT use metal measurers or containers for the very same reason.
Soap always contains three things - a fat (olive oil, in this case), a liquid (water, milk, tea), and lye (sodium hydroxide). Lye is available from online suppliers. It is usually very difficult to find locally. Believe me I have tried. Where it once used to be a common hardware or grocery store item, it has been removed from the local markets because of its use in illegal drug making. This is the same reason crystal drain opener is not made with lye anymore. I was fortunate enough to have an Amish neighbor provide me with lye for my soap making.
Basic All-Natural Castile Oatmeal Soap, Blender Batch
3/4 Cup Water (put it in the freezer until almost frozen)
4 1/2 tablespoons Lye
2 Cups Olive Oil (not evoo, just cheap olive oil. Again, measure and have at hand)
1/2 Cup Ground Oatmeal (I use closer to a cup)
1/2 Ounce of Essential Oil Scent (optional)
Some sort of mold
1. Grind your oatmeal in the blender beforehand. You can decide how chunky or powdery you would like it.
2. Put your 3/4 cup water in a heat-safe container (I use pyrex so it's an automatic measure). Place this in the freezer until the water just begins to freeze around the edges. Add in your 4 1/2 tablespoons lye crystals slowly and carefully. No splashing. Best to do this in a well ventilated area or perhaps outside - there are fumes. Stir well, very gently for a few minutes. The liquid will seriously heat up. Let is sit, well ventilated until it cools down a little. I insert a glass thermometer but a good indicator is waiting until the liquid is clear and the cloudiness disappears. You want to let the lye mixture cool down to around 100 to 120 degrees. Again, wear gloves, and do not touch it.
3. While the lye/water mixture is cooling, pour your 2 cups of Olive Oil into the blender. When cool enough, carefully pour the cooled lye/water mixture into the blender and put the top on. I cover the top with a towel for extra safety. On low, start blending the mixture together. It will reach "trace" in a minute or two. "Trace" is when it starts to thicken, the consistency of thick cream. Wait ten seconds before you take the top off - you know how a blender sometimes "burps" after it stops. Take the top off and add your ground oatmeal and essential oil "at trace." Put the top (and towel) back on, and blend for a few seconds to mix in the scent and oats. Don't go nuts and don't blend it too much - Once you reach trace, this stuff will thicken quickly, and you need to be able to pour it. Ideally, it's thin enough to pour, but not too thin. The consistency of a cake batter would be good.
4. Have your mold(s) ready beforehand. You can use anything flexible. They sell soap molds in craft stores; you can line a cardboard box with piece of a tough trash bag, or use old yogurt or sour cream containers. Could be anything as long as it is plastic and you could pour roughly the size of a bar of soap into it. If you used small plastic yogurt cups, pouring about an inch of liquid in each would make about six or seven. Or you could pour it all into one larger plastic thing (like one of those glad containers) and cut it into bars later.
5. Again, wait a few seconds before taking the towel and top off in case the liquid "burps." Carefully take the top off of the blender and pour about an inch into each mold.
6. Soap has to cure. Put it up out of the way and let it sit for three weeks. Most folks say the longer it sits the better it gets. Do not use the soap before it has properly aged. If you used one big mold and need to cut it into pieces, pop it out after a few days and cut it up, then put it away to cure. If you used smaller molds, pop it out after a few days and put it away to cure. Place the bars on something that will allow them to breathe, or at least stand them on end with a little space in between - they need air.
7. Keep the gloves on and carefully wash everything up.
This whole process takes about ten/fifteen minutes per batch. I've found the natural soap is wonderful and has been a miracle for dry skin. I find that rose essential oil goes well with thus oatmeal recipe, although most often I make it without scent.
Additional notes from city mouse- I've found really inexpensive olive oil/soy mixes in the dollar store. They work fine. Don't go for expensive olive oil - It doesn't matter. Also, you can mix oils. I've melted cocoa butter and subbed that for part of the olive oil (cocoa butter makes an extremely hard bar). You can melt down shortening and use that. Old timers used lard. Each oil has a different property, and you can combine the properties by combining oils. I've tried different combinations, but I honestly prefer the plain old olive oil. It seems to be the best for moisturizing. If you use a different oil, use an online lye calculator to check the amount of lye - different oils require different amounts of lye.
Here's a description of what each oil does - http://www.colebrothers.com/soap/oils.html
Here's an online lye calculator- http://www.the-sage.com/calcs/lyecalc2.php