The basic method of making margarine today consists of emulsifying a blend of oils and fats from vegetable and animal sources, which can be modified using fractionation, interesterification or hydrogenation, with skimmed milk which may be fermented or soured, salt, citric or lactic acid, chilling the mixture to solidify it, and working it to improve the texture.To produce margarine, first oils and fats are extracted, e.g. by pressing from seeds, and then refined.