Watermill of Risco de las Pencas

Watermill of Risco de las Pencas is a historic hydraulic mill in San Juan de la Rambla, Tenerife, protected as a site of cultural interest by the Canary Islands government. It sits on the left slope of the Ruiz ravine, right next to the TF-5 highway, at the starting point of a paved footpath leading toward the La Vera neighborhood.

What is the Watermill of Risco de las Pencas?

It is a former water-powered installation used to grind gofio, the toasted-grain flour that has long been a staple of Canarian cuisine. The site also goes by several other names — Molino de Ruiz, Molino de la Grieta, or Molino de Pico la Grieta — depending on local tradition and historical records. Milling continued here until 1942, after which the buildings fell out of productive use but remained as a physical record of the island's traditional water-powered agriculture.

Where does the name "Risco de las Pencas" come from?

The name refers to a distinctive cylindrical rock formation looming above the mill, also known as Roque del Molino. Prickly pear cacti — called "pencas" in Canarian Spanish — once grew abundantly around this rock. They had been introduced to the island in the 19th century during the cochineal boom, when the insects living on these cacti were harvested to produce a valuable red dye. The plants gave their name first to the rock, and eventually to the mill itself.

How was the mill built?

The complex consists of two rectangular structures. The main building housed the milling machinery, while the second is thought to have served as the miller's dwelling, a storage space, or an area for people waiting to have their grain processed. Beneath the main building lies a vaulted chamber, reached through an arched entrance, which contained the mill's mechanical heart: a wooden turbine wheel fitted with blades.

How did the milling mechanism work?

Water was channeled down to strike the blades of the wooden turbine housed in the underground chamber. As the wheel spun, it turned a shaft connected to a millstone positioned on the floor above, grinding grain into flour as it rotated. This setup — a common design among Canarian watermills — made efficient use of the terrain's natural slope and the steady flow from mountain streams, without requiring any external power source.

Why is this site protected?

In 2007, the mill was declared a Site of Cultural Interest (Bien de Interés Cultural) in the ethnological category. The designation preserves it as evidence of traditional milling craft and rural architecture typical of Tenerife's north coast, a region where ravines and mountain streams were harnessed for centuries to power local mills.

What else is worth seeing nearby?

The mill lies along a walking route toward La Vera, making it a convenient stop for visitors interested in local history and traditional rural life. Its position near the TF-5 makes access straightforward, and the surrounding landscape — dominated by the rock formation and the remaining mill structures — offers a glimpse into daily life in San Juan de la Rambla before the mid-20th century.

Frequently Asked Questions

Until when was the mill in operation? The mill operated until 1942, when traditional gofio grinding at the site came to an end.

What is gofio? Gofio is a traditional Canarian flour made from toasted grain, typically corn or wheat, and has been a dietary staple on the islands for centuries.

Where does the name "Pencas" come from? It comes from the prickly pear cacti that grew near the rock above the mill, introduced to Tenerife in the 19th century during the island's cochineal dye boom.

Is the mill officially protected as heritage? Yes, since 2007 it has been listed as a Site of Cultural Interest in the ethnological category.