The cork used in the manufacture of natural cork stoppers or technical stoppers must meet a number of conditions, including being free of certain anomalies. The use of NIRS (near infrared spectroscopy) technology has proven to be a valid technique for detecting yellow stain and corkbark, which are defects that must be avoided due to their harmful effects on the properties of the cork.

Resins
New drilling method for resin extraction in Segovia (Spain)
The traditional method of resin tapping is a very time-consuming activity since it requires the resin tapper to visit each tree every 10 to 15 days