Rancimat:

A machine for the measurement of resistance to oxidative rancidity. The method is based on changes in the conductivity of the steam distillate from material being oxidised at 100–120°C. These changes result mainly from short-chain acids (C1–C3) which are tertiary products of fat oxidation. Results obtained at these elevated temperatures must be interpreted with care when using them to predict shelf life since the mechanisms of oxidation change with temperature.

E.N. Frankel, Lipid Oxidation, The Oily Press, Dundee (1998).