I. SAMPLING PLAN
Individual lots of corks should be sampled using US Government Military Standard 105-D plan. From the sample taken, smaller sub-samples are randomly selected to undertake the following quality tests.
Guidelines for acceptance and rejection to follow US Government Military Standards 105-D Inspection Plan (reduced inspection), at the various acceptance levels as indicated per test below.
III. TEST PROCEDURES
A. Chemical Screening for TCA (Optional for 1+1 corks)
The number of bales to be tested will be in accordance with Mil Std 105-D L2 as applied to the incoming cork lot. Fifty corks from each selected bale are immersed in a 1.5L container of neutral dry white wine for 24 hours. The soak solution is screened for chloroanisole concentration using GC/MS (SPME) analysis on CQC equipment operated by ETS Laboratories. Acceptance is based on an AQL of 4.0. Failure of any Lot requires a secondary sampling at the Level3. Any lot failing to comply with standards in the second sampling will be rejected for domestic sale. Acceptance is based on the AQL 4.0 applied to either the second sampling or a combination of the first two analyises.
B. Sensory Test (Required for 1+1 corks without chemical screening)
The number of corks to be tested will be in accordance with Mil Std 105-D. Six corks from each bale taken as per III.A1 above will be immersed in a 500ml container of neutral dry white wine for 24 hours, then checked organoleptically for changes in sensory character when compared to a control wine. If TCA taint is suspected, an immersion test will be made from six corks from every bale. Any bale with TCA taint will be rejected.
B. Visual Quality:
Corks sampled, at minimum, will be in accordance with Mil Std 105-D (reduced). Individual corks are classified into predetermined categories depending on the physical qualities agreed on with the producer.
Cork moisture will be tested on a sample size of 25% of the Mil Std 105-D (reduced) per lot. A cork moisture instrument will be used. Cork shipments should be received with a moisture level below 7% average, with a tolerance per AQL 4.0.
If moisture level average is above 7% but below 10.5%, the following procedure may be followed:
- Corks are to be placed in a drying area which is physically separate from the storage area for accepted corks.
- When corks are resampled for reduced moisture levels, the cork moisture will be tested on a sample size of 25% of the Mil Std 105-D (reduced) per lot. A cork moisture instrument will be used. Moisture level must be below 7.0% average, with a tolerance per AQL 4.0.
- All sensory testing must be done again following procedure outlined in III.A before corks can be accepted into ongoing inventory of corks suitable for sale.
Cork dimensions will be checked on a sample size of 25% of the mil Std 105-D (reduced) per lot using an electronic or dial caliper accurate to +/- 0.01mm. Tolerance range per ISO3863 and acceptance at Military Standards 105-D. Diameter: as specified (+/- 0.50 mm) AQL = 1.5 Length: as specified (+/- 1.00mm) AQL = 4.0
E. RESIDUAL OXIDANTS:
One cork from each bale taken as per paragraph III.A1 above will be tested using a qualitative analysis involving the reaction of potassium iodide with residual oxidants in the presence of a starch indicator. A change in the test solution from clear to blue/violet color is a positive result.
IV. LOT DEFINITION
A lot is defined as a particular wood quality, size, and wash from an individual supplier in a single shipment. Sampling for chemical testing by SPME requires a maximum lot size of 250,000 corks. Larger lots will be divided into subsections below the maximum levels.
Permanent records of the quality control tests for each lot will be kept by the Supplier for a period of at least five years.