From bark to cork

"The production of a cork typically takes from 6 months to 1 year, starting with peeling the bark of the tree.". In Portugal, the world's largest softwood producer, the harvest season starts in May and ends in June. During harvest, workers are very careful to peel off the cork layer of cork oak (a deciduous oak tree with a soft and elastic "cork layer" in its bark that is particularly developed), not too deep, otherwise the big tree will die due to inability to resist parasites. After each harvest, it takes 9 years to peel the cork layer from the same oak tree. A healthy Quercus variabilis has a lifespan of 200 years and can only be peeled 18 times at most.
The peeled cork layer shall be stored in the open air. A good summer sun can dry the moisture in the cork layer; The continuous rain in autumn has cleaned the tannins contained in the cork layer. In jargon, this period of time is called the "stable period" of cork, which can last up to half a year, and if it grows longer, there is a risk of mold.
The dried cork can be cut into corks. Cutting is also an art, and experienced workers can judge the quality of a board's material with just a glance. The cut debris must not be wasted. They are collected and are good materials for processing polymeric corks.
Finished cork products should also be disinfected and selected to pick out products with defects such as fine edges or cracks on the surface. High quality corks must have a smooth surface with small and few pores.