Core properties

Cork oak tree or sobreiro (Quercus suber) is an evergreen slow-growing tree that can live up to 200 years or more. Cork, the outer bark of the cork oak, is a unique natural foam that has been harvested for millennia for a multiplicity of uses. Planks of cork are harvested via a process of stripping, using an axe to cut rectangular panels from the trunk and some branches and then levering these planks from the tree with the aid of the axe handle. This seasonal skilled work is undertaken from late spring to early summer each year and the harvesting process is done without any significant harm to the tree, which means cork is a sustainable biogenic material.

The cork we are using is sustainably harvested in the plains of Alentejo, South of Portugal and the manufacturing process takes place in the North of Portugal, known as the core of the portuguese and worldwide cork industry. 

Montado is a particular ecosystem, typical from the south of Portugal, consisting mainly of oak trees. These forests provide habitat for a vast array of plants and animals (160 species of birds, 24 species of reptiles and amphibians, and 37 species of mammals, a few at high risk of extinction, such as the Iberian lynx).

Montado is often pointed out as the lungs of the region of Alentejo (south of Portugal) because oak trees retain up to 14 million tonnes of CO2 a year, which it is a vital element to combat global warming and desertification, to control erosion, and to regulate the water cycle.

This ecosystem has been respected and cared for by local communities for several centuries.

Cork oak forests are also essential to local communities. Cork industry employs more than 100 000 people, and the highest paid agriculture work is precisely the cork extraction, a highly skilled job that requires years of training and specialization.

The process of harvesting the oak tree is called descortiçamento and workers need to be careful to extract the cork from the tree without hurting it.

This process is executed every 9 years, which allows the regeneration of oak trees.

Acorns are widely used in animal nutrition, particularly for grazing pigs. The pigs raised in Alentejo, eat acorns that give their meat a special flavour. These pigs, small in size and black in colour are called black or Iberian pigs, hence the famous pata negra ham.

Cuisine
The Lusitanians and other pre-Roman peoples of the Iberian Peninsula obtained flour from acorns with which they made bread, which is still done in the 21st century. Acorns are also used in some typical Portuguese culinary preparations. Nowadays, the food and cosmetic properties of acorns are beginning to be valued by scientists around the world, generating a potential market for Portugal.

Looking back, around 3000 B.C., there is archaeological and written evidence of cork being used for fishing floats in Egypt and China. However, the most frequently cited early account of the use of cork as a construction material is contained in author Pliny the Elder’s 37-volume Natural History. This records the use of cork as roof coverings for houses, as well as for nautical floats, bungs for casks, soles for women’s winter shoes and medicine.

Cork has long been used as a stopper for wine containers, with ceramic amphorae closed with cork plugs being included amongst archaeological finds from ancient Egyptian, Greek and Roman times.

Furthermore, according to some historians, the use of cork as a wine bottle stopper is credited to the monk Don Perignon in the Champagne region in the seventeenth century, especially the method of tying the cork stopper to the bottleneck so it could withstand the gas pressure of the sparkling wine.

Cork has therefore been put to opportunistic good use for millennia, in a range of building and other applications that take implicit advantage of its light weight, elasticity, relative water impermeability, surprising resilience, and insulative capacity which makes it feel warm to the touch.

Nowadays, cork is even used in the aerospace industry because NASA uses this material to provide thermal protection for every rocket part.

Bibliography:

Wilton, Oliver; Howland, Matthew Barnet – Cork: an historical overview of its use in building construction [Online]. International Journal of the Construction History Society. Vol. 35 No. 1 (2020).