Tripas as prepared Mexican style require care by the cook to avoid becoming rubbery. They are traditionally cooked in a "Disco" (dee-sko) which is constructed of two tilling discs (commonly used in the farming industry) welded to an iron pole in the center of the discs to form a wok like bowl on top of the pole with another disc about 8" - 10" below it. The tripas are placed in the top disc and filled with water while the lower disc is filled with wood or charcoal, thus creating the heat to cook the tripas. The tripas are boiled for several hours until tender, adding water as needed. Once they are tender the cook will allow the water to boil off and then finish the preparation by continuing to let them cook in their own fat.
Tripas are prepared to three levels. Soft preparation is attained shortly after the water boils off while the tripas are still tender with a velvet like texture. Properly prepared, they should not be rubbery but should have some firmness to them. Medium Crispy is reached by allowing the tripas to continue to cook in their own fat long enough for the exterior to crisp and harden. The center of the tripas are usually still soft and velvety. Finally Extra Crispy preparation is reached by allowing the tripas to cook long enough to get crispy all the way through. Sometimes lard is added to the disco to reach this level of crispness but the true "Cocineros" (Mexican chefs) contend that it is best done using their own fat.
Tripas in Portuguese cuisine, is beef stomach, and in the form of Tripas à moda do Porto (tripe with white beans) is considered the traditional dish of the city of Porto, whose inhabitants are informally known as tripeiros.