In order to guarantee the highest quality of ready‐to‐eat cereals and legumes, two different cooking methods have been applied: traditional cooking and sous‐vide. Ashes and metals content (magnesium, potassium, iron, zinc, and copper) has been determined and compared in 50 samples of red lentils, peas, Borlotti beans, pearl barley, and cereals soup. All the samples cooked with sous‐vide showed a significant increase in the content of minerals with the exception of potassium in cereal soup, iron in Borlotti beans, and magnesium in pearl barley. Ash content increased in legumes and in cereal soup cooked with sous‐vide method. The higher different ashes concentration between total samples cooked with traditional cooking and with sous‐vide was registered in zinc (+862 mg), iron (+314 mg), potassium (+109 mg), and copper (+95 mg). Sous‐vide is preferred as it provides products with a higher concentration of metals compared to the ones cooked with traditional cooking.