The models that best represented the experimental data of extractions with anhydrous ethanol were the second-order and the mass transfer based models. The difference between both models was considered not significant since their coefficients of determination (R2) were 0.9747 and 0.9731, and the absolute deviation (AARD) were 5.20% and 5.00% for the second-order and mass transfer models, respectively. These two models are showing that the extraction rate (k) and the equilibrium constant (C∞) increase as the temperature increases. However, at 25 ◦C, when the co-solvent is added the extraction rate decrease, showing that the mass transfer rate during the extraction is decreased due to the addition of a larger molecule (fatty acid methyl esters). At 40 and 55 ◦C, the extraction rate is less affect by the addition of the co-solvent. As the mass transfer model is based on theoretical diffusion phenomena and provided lower average deviations (AARD and RMSE, from Table 1), it was chosen to be set graphically as shown in Figs. 2–4.