Free fatty acids (FFA) content in butter influences its quality. Butter with high content of free fatty acids develops unpleasant smell and taste and becomes rancid. The free fatty acids are formed during ageing of butter due to hydrolysis or oxidation of fatty acid glycerol esters. Determination of FFA in butter is carried out by titration method. A weighed sample of butter is dissolved in neutralized ethanol, followed by addition of phenolphthalein indicator and titration with standardized sodium hydroxide (NaOH) solution until a pale pink color appears. The volume of NaOH consumed corresponds to the amount of free fatty acids present in the sample. The result is expressed as percentage of oleic acid. The factor 0.282 represents the milliequivalent weight of oleic acid.