Abstract: According to a first aspect, an ester oil, in particular for producing a hydraulic fluid and/or a lubricant, containing an esterification product from the esterification of at least one monoalcohol with at least one polycarboxylic acid, is characterized in that the monoalcohol and/or the polycarboxylic acid originates from renewable raw materials. According to a second aspect, an ester oil, in particular for producing a hydraulic fluid and/or a lubricant, containing an esterification product from the esterificati-on of at least one monocarboxylic acid with at least one dialcohol, is characterized in that the dialcohol and/or the monocarboxylic acid originates from renewable raw materials.