Cork is considered one of the most important forest products, the economic activities linked to it are clearly included in the Bioeconomy. It is a natural, renewable and sustainable raw material with a low environmental impact. Its unique properties make it ideal for different applications, among which wine sealing stands out. The use of cork contributes to the conservation of cork oak forests, a Mediterranean ecosystem with high biodiversity that fulfills a fundamental ecological function as a protector against the advance of desertification and erosion, and as a carbon sink. In addition, it contributes significantly to the rural development of the areas where the cork oak forests are located. Spain ranks second in the world in terms of area covered by cork oak forests (27%) and cork production (31%).
The quality of cork is one of the most relevant issues for the cork sector since it determines its industrial application and therefore its value. The main variables that are evaluated when classifying cork according to its quality are the thickness of the cork plank and its appearance. The main indicator of the appearance of the cork, and consequently of its quality, is porosity.