Cork Treatment

M. A. Silva is a company that produces natural corks for the wine industry. Our process is vertically integrated from the purchase and early preparation of corkwood, through secondary transformation, and further processing to the completion of the final product.

Throughout this process, special attention is paid to critical points and all work instructions and control operations are well-defined and documented in order to ensure a consistent standard of quality and process analysis aiming at the continuous improvement of our system.

Outdoor Seasoning

Cork planks are stored for a period of 6 to 9 months. The planks piles are formed bearing in mind a certain number of rules to allow good air flow while piling them up on cement floor to avoid direct contact to the soil.

This operation makes the sap dry out, allows reduction of moisture in the cork planks, oxidization of some compounds (particularly the phenols) and a compensation of the intrinsic forces of cork layers in the planks due to cork growing rhythm.

Boiling

Boiling is a very important process — this is where polyphenol compounds are extracted, as are the long chain carbonated compounds, such as polysaccharide, waxes and polyterptenes. They are basically sterilized in boiling water above boiling temperature, under pressure, for about 60 minutes. M.A. Silva has innovative, high-tech boiling equipment that provides added efficiency to the process.

Stabilization after boiling

After boiling, the cork planks rest for 2 to 3 days. They are carefully piled on stainless steel pallets to allow air circulation in a controlled environment to obtain a suitable dimensional stabilization.

Punching

Cork planks are cut into strips a little bit wider than the intended length of corks to be punched. Then, they are punched off the strips with punching tubes using diameters slightly bigger than the intended diameter of the corks to be created.

Sanding

Corks dimensions (length and diameter) are rectified after pre-drying to respect normative requirements.

Washing / Maszone System®

In this paramount stage of the cork production process, the most advanced technology is used by M.A. Silva — gaining customers’ continued trust.

Our washing facilities guarantee a complete disinfection of corks, additional extraction of compounds (mainly phenol compounds) and provide a homogenous look to the corks.

Drying

Immediately after washing, it is mandatory that corks undergo the final drying process to bring down their moisture to recommended values. The combination of controlled atmospheric conditions (temperature and humidity) with injection of ozone in the environment prevents microbiological growth.

Sorting

At M.A. Silva, visual sorting is a sensitive, vital operation where corks are selected into different grades and critical defects are sorted out and segregated. This process is supported by a set of samples previously accepted by customers.

Branding / Printing

Branding and printing is carried out according to customer’s instructions executing their typeface and artwork, using either printing (food grade ink) or branding (fire).

Coating

The objectives of the process are to make a barrier in corks against both liquid absorption and migration of compounds to the wine and to lubricate the corks to provide optimal insertion and extraction.

Packaging

When corks are ready-to-use, they must be protected against external environment — they are vacuum-packed in polyethylene bags of 1,000 corks and a suitable gas is injected to prevent from microbiological development. Bags are then repacked into cartons to guarantee their integrity during transportation.