Definition
Saponification
The chemical reaction in which an alkali, either sodium hydroxide for bar soap or potassium hydroxide for liquid soap, reacts with fats and oils to form soap and glycerine.
Every oil has its own saponification value, the amount of alkali it needs, which is why a recipe cannot be scaled by weight alone and why the alkali figure must come from a proper lye calculator rather than from an estimate. This site gives planning and costing tools for soap and deliberately does not give formulation maths.
Tools that use this term
Soap Batch Size Calculator
Turn a bar count and bar weight, or a mould volume, into the oil, water, fragrance and lye weights a soap batch is built from.
Soap Mold Volume Calculator
Volume of a rectangular, cylindrical or loaf soap mould in cubic inches and millilitres, and the batter weight it holds at 0.4 ounces per cubic inch.
Soap Ingredient Cost Calculator
Cost the oils, lye, water, fragrance and colour in a soap batch, per batch and per bar.