SV = 56.1 × N × (V_blank − V_sample) / W
The saponification value (SV) is the mg of KOH required to completely saponify 1 g of fat or oil. It is determined by refluxing the sample with excess KOH, then back-titrating with HCl: SV = 56.1 × N × (V_blank − V_sample) / W. The SV is inversely related to the average molecular weight of the fatty acids: lower MW fatty acids (like those in coconut oil, SV ≈ 257) have higher SV than long-chain fats (beeswax, SV ≈ 136). SV is used in: soap making (to calculate the exact amount of NaOH or KOH needed — the "SAP value"), quality control of edible oils, biodiesel production, and cosmetics formulation. The approximate average molecular weight of a triglyceride = 3 × 56100 / SV.