Using an abrasive stone, the punched corks are polished to the required length and evenness.
 

The polished corks are sorted by a machine, which photographs and classifies each cork by quality into categories. The categories correspond to the number of lenticels or defects visible in the body of the cork — those with the most lenticels are used for lower-grade products such as colmated corks.
 

They are then washed in a solution of hydrogen peroxide (H2O2) to bleach and sterilize the corks and eliminate microorganisms that might contribute to cork taint.


 

After washing, the corks are dried in industrial ovens or with sterilized air to the correct moisture content.

 

This article sponsored by Amorim Corks