TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The alcohol is single or multiple 1-5C-alcohols. The acid, heterogeneous ion-exchange-resin catalyst is strong acid polymer macroporous resin with free sulfonic acid groups. The raw material is vegetable fats, animal fats, vegetable oils and/or animal oils. Preferred Process: The water is separated after the reaction of the free fatty acids. The water and alcohol are separated after the reaction of the free fatty acids. The separation of the water takes place selectively with the help of a membrane. The water together with a part or the total quantity of the alcohol is separated by evaporation. The reaction or the further reaction of the free fatty acids takes place at 80-95 degrees C. In the process, additional alcohol is added before the further reaction. The step (c) is carried out more than once, preferably the progression of step (b) and (c) is carried out more than once. The alcohol is added to the raw material according to step (a) in a molar ratio of 5-40, preferably 10-20. At least the step (a) or step (c) is continuously carried out in a reactor with a catalyst fixed bed. A catalyst load of 0.1-4 kg/kg.hour, preferably 0.2-1.6 kg/kg.hour is present in the raw material with an acid number of less than or equal to 40 in step (a) and/or step (c). The catalyst load of 0.3-10 kg/kg.hour, preferably 0.5-3 kg/kg.hour is present in the raw material with an acid number of greater than 40 in step (a) and/or step (c). EXAMPLE - A mixture (1120 g/hour) of rapeseed oil, oleic acid and linolenic acid with a content of free fatty acids of 12.5 wt.% was conducted with 267 g/hour of methanol at 83 degrees C and a pressure of 4 bar with a retention time of 10 minutes over a catalyst fixed bed made of acid ion-exchange-resin (650 ml). The catalyst particles had a diameter of 0.8 mm and were immobilized in a fixed bed reactor with a catalyst bed length of 2.08 m to obtain a catalyst load of 1.16 kg free fatty acid per kg catalyst per hour, and a superficial velocity of 3.5 mm/second. A turnover degree of 98.3% was achieved with a molar ratio of methanol to fatty acid of 16.8:1.