Abstract: A method and apparatus is disclosed for determining the oxidative stability of pure lipids or lipids incorporated into complex matrices containing other, non-lipid ingredients. An exemplary test system includes a first container adapted to contain the sample and a heater for heating the sample to make it give off an effluent gas. A second container contains a collection fluid through which the effluent gas can be passed. A sensor within the second container measures pH, acetate, ammonia, and/or formate. An optional computation device in communication with the one or more sensors determines a point in time at which the level of one of pH, acetate, formate and/or ammonia changes suddenly.