Selection and extraction of the bark
Selection and analysis:
Six
months before harvesting the bark, our technical staff goes to the forests and extracts different samples of bark from the cork
trees to be analyzed. Under no circumstances are oak trees selected from
forests that have combined oak with other vegetable or crop production.
We never use forests that have been sprayed with chemicals or pesticides.
Purchase of the rights of extraction:
When
we encounter an area with an acceptable quality of bark, a contract is
then signed with the owner of the forest for the rights of extraction of
the bark.
Extraction of the bark:
We
send our own teams to harvest the bark from the cork trees. Once the bark
is extracted it is immediately sent to the treatment plant in Ciudad
Real (Spain), where it is classified and treated.
Preparation
of the cork
Boiling process:
In
order to obtain a flat bark and allow classification and curing, the
bark is first boiled for 45 minutes at 100ºC (212ºF). This process
eliminates tannins, lignin, and any parasites that may be present in the
bark.
Classification and preparation:
In
our facility in Eslida, Castellón de la Plana, raw cork bark is
classified according to thickness and grade. All bark containing defects
such as green bark, yellow stains,
wormholes, etc. is rejected by the technical staff.
Curing
process:
For
a period of one year, the bark is stored without any further processing.
During this time, the bark is cured removing part of the lignin and improving cork properties. During a second process the bark
is stored in an open-air shelter, until the curing process is completed.
Second boiling process:
To
finally rid the bark of lignin, tannins, microbes and prepare the cork
for processing, the bark is boiled again.
Cork manufacturing process
Slicing and punching:
After
the second boiling, the bark is first sliced in different lengths and
then punched to make the corks.
First visual selection:
All
corks are submitted to a manual classification. Corks which do not
meet our standards are removed.
Third curing process:
The
punched corks are dried and treated through a grinding process in
compliance with UNE and Catalan Corks Regulations (NCS).
Washing:
Corks
are washed with a hydrogen peroxide solution for 45 minutes. During this
time, the PH of the solution is monitored periodically during the
process to ensure that no oxidizing agents remain.
Drying:
Corks
are dried in warm air for 40 minutes at a temperature between 45 and 55º
C (113 to 131º F), followed by a dust removal process.
Electronic grading:
Once
dry, corks are selected electronically using artificial vision systems.
Manual
grading
After
the electronic grading, the corks are manually examined by our technical
staff. Both electronic and manual grading help to determine a more
objective and homogeneous quality.
Cork branding:
We
are capable of printing any logo on your corks using ink printing or a
fire branding system. The ink used meets FDA food-safety standards.
Stabilizing:
After
branding, corks are placed in a stabilizing room to attain the correct
humidity level.
Coating:
Corks
are coated with a mixture of paraffin and silicone. This coating is
customized to the customer’s needs depending on their bottling machine.
Final
visual control:
When
the corks come out of the treatment drums, they are subjected to a last
visual control carried out by the technical staff.
Packing:
All
corks are packed in 1,000 unit bags, which are vacuum sealed and
conditioned with SO2 for microbiological stabilization.
Delivery:
Corks
shall be delivered to the wineries in bags placed inside cardboard boxes,
palletized for easy handling and protection during transportation. Each
box is labeled with a product description.
Technical service
Rich
Xiberta technical staff is always available to give professional advice
to wineries during the bottling process to ensure the best results and
the best corking.
Quality Controls
We
carry out a number of quality controls throughout the entire process in
order to ensure that the product exceeds the customer’s expectations.
Quality
Control Report:
Each
order is delivered with a quality control report. This report
exhibits physical and microbiological analyses certifying the quality of
the product.
Humidity Control:
At
different steps of the production process we monitor the humidity of the
corks to be sure that it remains between 5 and 8%. If the level is below
this range the stopper might break or shed dust, and if it is above, the
stopper could give way to molds. When the humidity
level is incorrect, the corks are placed in the stabilization chamber
until they regain optimal humidity.
Physical
controls:
Besides
humidity, other elements may have an effect on the stopper. Every lot
undergoes strict physical tests complying with the Catalonian Oak Norms
(NCS) and UNE rules.
Organoleptic controls:
Another
important analysis carried out is the organoleptic control test. A
representative sample of the lots is submerged in white wine for 24
hours, and after this time our tasting team evaluates the results.
TCA
Controls
TCA,
the chemical compound that produces off-flavors in wine is a
growing concern for winemakers. At Rich
Xiberta, we take every step to keep the TCA level to the
lowest in our stoppers. Our concerns
about this matter have led us to reach agreements with Universities and
Research Institutions to find ways to eliminate it..
