The most ideal food was that which most closely matched the humour of human beings, i.e. moderately warm and moist. Food should preferably also be finely chopped, ground, pounded and strained to achieve a true mixture of all the ingredients. White wine was believed to be cooler than red and the same distinction was applied to red and white vinegar. Milk was moderately warm and moist, but the milk of different animals was often believed to differ. Egg yolks were considered to be warm and moist while the whites were cold and moist. Skilled cooks were expected to conform to the regimen of humoral medicine. Even if this limited the combinations of food they could prepare, there was still ample room for artistic variation by the chef.