Hand made soap is a beautiful thing. But for shaving what you want is lather. You do not want the lather to clean. What you want is it to soften the hair, lift it from the skin and provide a slick smooth glide. There are some people who insist that clay adds to the slickness of the soap and others who believe that it should be avoided as all it does is dull the razor. I see no need to add clay to my shave pucks as I have smooth silky glide without adding clay.
Other recipes will use olive oil however I don't. Olive Oil is wonderful for soap. But I want lather not a cleaning soap. Olive Oil can get slimy and I don't want slime. So I have found that simplicity is the best when making a shave soap. I even hate calling it soap because soap cleans. What we want is lather.
First of all the basis of shave soaps is stearic acid. That is a property of an oil such as tallow, shea, mango and palm. Other oils also have stearic acid. So if you are trying to develop a shave soap first look at the oil properties and choose those with high levels of stearic acid. You will also notice that the oils that are high in stearic acid are also high in palmic acid. I combine the total stearic and palmic acids and aim for a combination of over 60% in my shave pucks.
Another component is the type of lye that is used. NaOH and KOH in combination seems to produce more lather from the experiments by Kevin Devine. So I use a 60/40 ratio of KOH/NaOH in my recipe.
This is a basic recipe for 1 lb of Shave Soap.
.85 oz NaOH
2 oz KOH
6 oz Water
6.4 oz Tallow (I use organic grass fed and personally rendered)
6.4 oz Stearic Acid
3.2 oz Shea Butter
1.6 oz Vegetable Glycerin (after cook)
Due to the high heat necessary for stearic acid I use a hot process method of making this soap.
I use a stick blender now to incorporate the glycerin and fragrance. As soon as you have a creamy consistency it is time to mold. You can use mugs, silicone molds, PVC tubes, Pringles Cans, whatever you want to use - just make sure you can get it out so I suggest lining whatever you use. Then just wait for the soap to cool. Since this is hot process it does not need to cure and is ready to use the next day. You don't need to worry about the soap getting harder because it will be used with plenty of water and is already saponified from the heat of the hot process method.