text: To determine saponification value, the sample is treated with an excess of alkali (usually an  ethanolic solution of potassium hydroxide) for half an hour under reflux. The KOH is consumed by reaction with triglycerides, which consume three equivalents of base. Diglycerides consume two equivalents of KOH.  Monoglycerides and free fatty acids, as well as by other esters such as lactones consume one equivalent of base At the end of the reaction the quantity of KOH is determined by titration using standard solution of hydrochloric acid (HCl).  Key to the method is the use of phenolphthalein indicator, which indicates the consumption of strong base (KOH) by the acid, not the weak base (potassium carboxylates). The SV (mg KOH/ g of sample) is calculated as following:
  :where:
  : is the volume of HCl solution used for the blank run, in mL;
  : is the volume of HCl solution used for the tested sample, in mL;
  : is the molarity of HCl solution, in mol / L;
  : is the molecular weight of KOH, in g / mol;
  : is the weight of sample, in g.
  For example, standard methods for determination of SV of vegetable and animal fats are as follows:
  The SV can also be calculated from the fatty acid composition as determined by gas chromatography (AOCS Cd 3a-94).
  Handmade soap makers who aim for bar soap use sodium hydroxide (NaOH), commonly known as lye, rather than KOH (caustic potash) which produces soft paste, gel or liquid soaps. In order to calculate the lye amount needed to make bar soap, KOH values of SV can be converted to NaOH values by dividing KOH values by the ratio of the molecular weights of KOH and NaOH (1.403).