The swine with this Protected Designation of Origin are fed with acorn and grass, or with both of them mixed with fodder, or with fodder alone. The habitat of these pigs is made of holm oaks and corn oaks. These pigs are Iberian breed, pure breed or crossbreed with Duroc-Jersey, but with at least 75 % Iberian breed.
- Geography: Castilla y León, Castilla la Mancha, Extremadura and Andalucía provincies. The designation of origin is called "Guijuelo" because the curing process is made in Salamanca, although there are some other important places such as Leadra, Tamames, Béjar, Campillo de Salvatierra and so on (up to 78 municipalities).
- Weather: the winter is long and cold, and the summer is pretty long and hot, with some cool winds. The medium altitude is about 1000 meters - the Sierra de Gredos and the Sierra de Béjar stand out from this point of view.
- Classification: the pigs with this PDO are divided into two groups:
- Iberian acorn serrano hams and picnic shoulders: these pigs are fed with acorn and grass. They are also marked with a red seal and a Reserva (reserve) cigar band, which make recognizable their identity.
- Iberian serrano hams and picnic shoulders: these pigs are fed with natural food, complementing the acorn, or they are just fed with fodder. A yellow seal and the white cigar band differenciate them from the acorn fed pigs.
The Guijuelo pigs can be of two types: fed with acorn or fed with natural fodder
- Manufacture: once the animal is slaughtered, it is taken to a warehouse where the salting of the ham from Guijuelo takes place, where the hams and the picnic shoulders are covered with sea salt. The salting period is calculated as approximately one day per kilo.
Later, the pork pieces are taken to the natural drying warehouses, where the maduration process begins. This last process ends inside the cellaries, in a very slow way. Once the salting phase of the ham and of the picnic shoulders has finished we go to the next phase, which is the washing. It consists in washing away the salt all over the surface of the pork pieces. Then the ham and the picnic shoulders are outlined.
Then, the settlement is realized, during which the water and the humidity slowly dissapear from the surface of the pork pieces. The next phase is the drying of the serrano ham and of the picnic shoulders, performed in natural drying rooms. At last, the hams are taken to cellars where they are hung.
- Their shape is elongated and slim, they still have got the hoof, which is black.
- The serrano hams from Guijuelo must weigh more than 4,5 Kg and the picnic shoulders must weigh 3,5 Kg.
- The shade of the pork may vary from a reddish and purple colour to a light pink. When one cuts the pork piece he/ she can notice the fat and, sometimes, some white spots (this is the tyrosine which has christalyzed within the muscles, due to the low salt level during the manufacture). This type of fat is brilliant and presents a goldish shade.