It is a variety of bull made in various parts of the country. Because it contained the blood, it was one of the last products to be made for slaughter and the last cuts of the pork were usually added.
The classic black bull recipe incorporates rinds, bacon, remaining meat pieces and blood. Currently, and according to each producer, the little ones and ashes are also added, as well as lean meat or tongue. All the ingredients are kneaded, seasoned with salt and pepper and stuffed into the casing, usually gut, cooked and left to dry for a few days. This boil is highly appreciated grilled or fried, but it is also eaten cold with bread with tomato, sandwiches or hors d'oeuvres.

It is found in delicatessen shops near the production areas. It is sold throughout Catalonia.
Made from meat, fat and pig's giblets, it is a very energetic food, rich in fat and cholesterol, but at the same time rich in proteins of high biological value and vitamins of group B. By containing the blood of pork, it also becomes an excellent source of iron. Within a varied and balanced diet, its occasional consumption is totally recommended.