Making Colmated Corks

Colmated corks consist of a solid natural cork body and a fine granular cork coating. Craftsmen hand punch bodies from strips of natural corkwood that have been boiled and cleaned using the state-of-the-art Dynavox® boiling process. All M.A. Silva corks are hand punched, resulting in the highest quality cork closures.
Electronic sorting machines identify and separate the bodies that are structurally sound, but do not meet the visual standards of higher natural cork grades. These will become colmated corks. Corks that contain significant structural defects are ground into particles for our Silktop technical and Pearl Micro-agglomerate corks.
 Cork bodies intended for colmation must be structurally sound, exhibiting no major cracks or chips.
Inside the automated colmation machine, cork bodies A food grade adhesive is introduced. The drum continues evenly coats the surfaces, including the exposed lenticels and other pores.
  Only the cleanest, highest quality cork particles are used in the colmation process. During the manufacturing of corks, including our colmated corks, each body passes through a rectification process. This operation perfects the ends and cylindrical surfaces ensuring proper insertion, extraction, and appearance in the bottle. Vacuum equipment directly collects the particles for colmation. 
As with other M.A.Silva products, the cork particles are transported and stored in containers that do not promote bacterial, fungal or chemical contamination. Internationally recognized standards of quality are characteristic of M.A. Silva facilities and processes. These guidelines ensure excellent repeatability and full traceability.


With the adhesive evenly distributed, cork particles are added to the tumbling cork bodies. The colmation drum rotates until all the surfaces receive an even coating of particles. While not damaging the bodies, the impacting force is sufficient to drive the particles deeply into the open pores. The several
tumbling process results in a smooth, consistent fill.
After a carefully controlled setting period, the filled corks pass to a rotating, perforated drum where loose particles fall. The rejected dust becomes raw material for insulation and other non-wine cork related products.
The colmated corks receive a final cleaning with the Maszone® process. Using ozone and hydrogen peroxide, Maszone® washing removes residual off-aroma polyphenols such as TCA, while eliminating micro-organisms and their spores. The tumbling action performs the final phase of removing particles not firmly attached. The completed corks leave the operation dust free, with neutral sensory characteristics.