The castle was never conquered and was successfully defended against the King of Castile in the 13th century. The successful completion of the Reconquista at the end of the 15th century ended its military significance. Although it fell into ruin in the following centuries, since 1971 it has progressively been restored by its private owners. It can be visited with permission from the owners.
The namesake of the castle, zafra, is a somewhat contested term linguistically. It is accepted that the word entered Spanish from Arabic, but there is some disagreement about the precise origins of the word and its significance in Spanish. In Spanish speaking countries the word zafra refers to the late summer or early autumn harvest of crops such as sugarcane, a staple brought from Arab lands. Some believe the term is derived from the Arabic zāfar or zafariya meaning "harvest time", while others believe the term derives from saʼifah meaning "gathering time".
The castle is situated atop a large rock in the Vega de Zafra at an altitude of 1,400 metres (4,600 ft) in the Sierra de Caldereros. The upland area is characterised by sloping meadows interspersed with heavily-eroded sandstone outcrops, one of which is occupied by the castle. It occupies the whole of the outcrop, which runs in a north-east to south-west alignment. A wall encloses the top of the outcrop, linking the entrance tower at the south-west end to the main buildings at the north-east end. Traces of buildings – possibly part of an outer enclosure that might have incorporated structures such as stables or supply stores – can be seen in the meadow surrounding the castle.
There are four principal areas within the wall. At the far south-west end is the entrance tower, after which is an open courtyard. This in turn leads to the enclosed Place of Arms, a troop assembly area within which were the castle's cisterns. This gave access to the highest point of the outcrop, which is occupied by the Tower of Homage, the castle's keep which housed the lord's chambers and kitchens. Two floors are within, connected via a spiral staircase that affords access to the castle's upper terrace and broad views over the surrounding countryside. The castle is thought to have been capable of accommodating as many as 500 people.
The castle is privately owned; its two main towers have been substantially restored. Its exterior is freely visible but visits to its interior require the permission of the owners, the family of Antonio Sanz Polo of Molina de Aragón. It is some way from the nearest paved road but can be reached on foot in a day-long hike or in a sufficiently rugged motor vehicle via a dirt road leading up from the village of Hombrados.