Using a digital scale, weigh your water and lye in separate containers. Add the lye to the water (SNOW FLOATS ON THE LAKE), and stir until dissolved. It will shoot up in temperature. Set your lye water in a safe place, marked as poison.
Using your digital scale, weigh your oils and butters and put them in a large pot. Melt over low heat until they reach 140 degrees.
Allow your lye water and oils to cool to 100-120 degrees. They should be within ten degrees of each other.
Prepare your mold, color, and fragrance before blending. When you are ready, pour your lye water into your oil pot and blend using a stick blender. You are looking for "trace", which means your ingredients have combined into a soap batter. You will see no visible oil spots, the mixture will appear somewhat opaque, and if you lift your stick blender, a trail of batter will sit on top of the liquid instead of immediately sinking in. When the trace is reached, stop blending.
Mix in any color you would like to add and stir by hand. Add fragrance last as it will cause the soap to set up quickly. Add one tablespoon at a time and stir by hand after each addition.
Quickly pour into your mold. Spray with rubbing alcohol to prevent soda ash, if desired. Place in a turned-off oven and allow to cure overnight.
Unmold, and cut into bars. When soap is finished curing, it will not be given off any heat. Unmold, cut into bars, and allow to finish curing in layers of newspaper, turning occasionally, for three weeks.