African Cork Suppliers | Quality Standards


	Quality Standards


	At African Cork Suppliers we strive to deliver products of the highest quality to all our customers. In order to achieve that, we have implemented an ISO 9001:2000 compliant Quality Management System, for which we have been certified since January 2007.

	Our quality control laboratory controls the products in three main areas:
	1. Incoming Inspection 2. Work In Progress Quality Checks 3. Final Inspection

	1. Incoming Inspection

	As soon as corks arrive at our premises, samples are drawn randomly and submitted to the following testing:

	a) GC Analysis by independent laboratory – Quantum Laboratories b) Dimensional Analysis c) Humidity Analysis d) Sensorial Analysis e) Visual Evaluation


	a) GC Analysis by independent laboratory
	As we belong to the South African Cork Council, we have to adhere to the requirements set for members with regards to testing of corks. With regards to GC analysis, samples are drawn according to the sampling plan recommended by the SACC, which is based on the Military Standard 105E. Samples are then sent to Quantum Laboratories for TCA analysis by Gas chromatography machine and results for batches send to us. Based on these results (SACC specification for TCA is 4 p.p.t) batches of corks are either accepted for production or rejected and returned to our supplier.

	b) Dimensional Analysis
	This test is done to verify that the corks received are the correct length and diameter. At the same time, the ovality of the corks are calculated and verified. This test is done in our laboratory, using a calibrated calliper connected to a computer program that captures the data and calculates the average measurements as well as other values such as density, weight etc. The amount of samples to be drawn is also stipulated in the SACC requirements and based on the Military Standard 105E.

	c) Humidity Analysis
	The humidity of a random sample of corks are checked by digital moisture meter to ensure that the moisture levels of the corks are between the recommended levels of 4-8%, depending on the type of corks. This data is also captured on computer. The amount of samples to be drawn is also stipulated in the SACC requirements and based on the Military Standard 105E.

	d) Sensorial analysis
	Sensorial analysis (or olfactive testing) is done to identify any negative aromas that may be present in the corks. This test is done by soaking individual corks in a 10% alcohol solution overnight, after which the aromas in the solution is evaluated by smelling. Any negative aromas are recorded, and retests are done to confirm the aromas. We have downscaled our sensorial analysis sampling plans in the last year, as we now focus on GC testing instead, which is more accurate than the human nose and can detect the components at very low levels.

	e) Visual Evaluation
	A representative sample of corks from each grade and size received is drawn from various bales. These corks are then inspected visually, and placed in the correct category – indicating that it is either the correct quality, above standard or below standard. Special attention is given to the amount of critical defects found on the corks. The amounts of corks found in the different categories are then calculated in percentages and the lots accepted or rejected on this basis. If the overall quality of the sample is considerably lower than the standard, the results are discussed with management and the suppliers, and a decision will be taken as to whether the corks will be sorted by electronic sorting machine, to remove the sub-standard corks, or the batch rejected as is and returned to the supplier.


	2. Work in Progress Quality Checks

	a) TCA Testing b) Visual Inspections c) Humidity checks d) Verification of surface treatment


	a) TCA Testing
	When an order is received and the corks are selected for the order, the first check done is to ensure that the corks selected have been tested for TCA either during the incoming inspections by Quantum Laboratories, or during our in-house random testing. If the individual bags have not been tested by GC in the last 6 months, samples are drawn and tested in our laboratory. As we have our own GC/ECD machine, we are able to test every bag for TCA if necessary. For small orders, we do test every bag used for the orders, but for large orders of more than 200 000 corks, we try to test at least ½ - ⅔ of the total amount of bags we use. This sampling plan is far more extensive than the plan used by the independent laboratory, but we feel that this increases our confidence in the low TCA levels of our corks. If bags fail the first GC test, we do retests on the bag to ensure that the results are indeed accurate. If the bag fails the retests as well, the bag is rejected, isolated and returned to the supplier. The GC results of the bags are also indicated on the quality report, which accompanies every cork order to the customer.

	b) Visual Inspections
	When an order is started in the printing department, a visual inspection is done on the first corks printed to confirm that the correct corks and artwork is used for the order. As soon as there are sufficient corks printed to draw a representative sample, a visual grading is done on a sample of corks, to ensure that the visual quality is in line with what is required by the customer. This check is done by one of the laboratory staff. If the corks are found to be below the standard, steps are taken to correct the visual quality of the corks – usually by hand- or machine sorting the corks prior to printing. In the case of large orders, printed over a few days, random samples are taken over the printing period to ensure that the quality stays constant throughout the order.

	c) Humidity checks
	The humidity of the corks is tested prior to surface treatment processing of the corks. It is at this stage that the humidity levels of the corks can be adjusted, if necessary. Once the corks have been treated with silicone, it is very difficult to adjust the humidity of the corks, as one of the functions of the surface treatment is to seal the cork against a certain degree of moisture. If the humidity of the corks needs adjustment, the humidity is checked again after the adjustment is made to ensure that the moisture levels stay within the recommended range.

	d) Verification of surface treatment
	Once the silicone treatment is done on the corks, a random sample of treated corks is brought to the laboratory for verification. This is done by inserting the corks into wine bottles, using a hand corker, and pulling the cork out of the bottle using a cork extraction meter. This measures the amount of force needed to pull the cork out of the bottle. If the values are above or below the specifications, steps may be taken to adjust the amount of treatment applied to the corks, to ensure the best performance of the corks.


	3. Final Inspections

	After the treatment of the corks is completed, a sample of corks is brought to the laboratory for the final testing. The results of these tests also appear on the quality report, which accompanies the order to the customer with the delivery note. The following tests are done on the sample brought to the laboratory, after which the sample is kept as a reference sample of the order. 1. Dimensional Analysis 2. Humidity Analysis Other tests could be done on request by the customer. These include: 1. Quantification of dust residues 2. Quantification of surface treatment 3. Capillarity Tests 4. Detection of Oxidants / Peroxides 5. Extraction tests