Cork comes mostly from Portugal although Spain, Italy, and North Africa are also producers. Rumor has it that China has vast cork oak forests and so we might expect to start seeing Chinese corks one of these days. There are two main classifications of cork: natural and technical. A natural cork is punched, or cut, out of the bark of a cork oak tree, washed, sometimes printed with food-grade ink, and coated. The coatings agents typically used for natural corks are block paraffin (basically drop some paraffin in a huge tumbler with corks and let it spin for a few minutes) although this is not very common anymore, and emulsions of paraffin and silicone. In this case, the emulsions are sprayed, paraffin first and then silicone. The paraffin puts a protective layer over the cork in order to minimize any potential transfer of off-odors or spoilage agents that may be in the cork such as TCA (tri-chloro-anisole). The silicone, for its part, acts as a lubricant and allows for the easier extraction of the cork.

Technical corks are also made of natural cork but of pieces instead. During the punching out of the natural from the bark, a lot of good cork material is left behind but is too small to form a cork. So, it can be chewed up into small pieces which are then reconstituted using glues and latexes and formed into the shape of a cork. Some of these corks are made up entirely of chewed up bits of cork while some have one or two disks of natural cork on each end, thus giving the possible impression or feeling to the consumer that it is a natural cork. No one is trying to deceive anyone here but, rather, just trying to preserve a specific impression. The wineries are motivated to use technical corks because they preserve part of the image of natural corks but are substantially cheaper.

In terms of coating, technical corks are usually coated with an elastomer, one example is CAF--imagine a latex glove on the cork. As you can see, all coatings are petroleum by-products and, although technically inert and food-grade, the reality is that they can impart chemical flavors to the wine. Whether they come from the glues, latexes, or coating, we have seen (well, smelled) chemical overtones to white wines when we conducted trials. Also, the coatings do not always work 100% of the time and it is possible for cork (or wood) odors to be imparted to the wine. For a red wine this is much less of a problem but, for a white wine, the odors or flavors from wood or petroleum can be definitely be noticed on occasion.

There are other things that can be done to corks such as painting them in order to cover ugly blemishes, or filling in large cracks with cork dust and glue. Those happen rarely in the American market and so we will not go into detail here.

Lastly, a comment about coloring: you will sometimes notice that corks are quite pink and, other times, they are quite white. Natural cork, as it comes off the tree, is pink; actually, it can be quite brown. However, over the years, wineries have found that customers prefer white corks and, therefore, during the washing process, the color is removed. Up until the 1990's, the cork producers used bleach which they then neutralized with oxalic acid. In the early 1990's, due to a demand from a large British importer, they ceased using oxalic acid without realizing that bleach is actually a precursor to TCA. So, many corked bottles later, they decided to switch to other chemicals such as hydrogen-peroxide. Some wineries still insisted on natural-looking corks although the majority seem to prefer white. Either way, the color doesn't affect the performance of the corks.

For our Cabernet Sauvignon, we are committed to natural cork and will continue conducting exhaustive trials in order to make sure that the supplier we use has provided us with lots that are not contaminated and will not impart off-odors, as best as we can. We believe that natural cork complements the experience that our customers expect when opening a bottle of our Cabernet Sauvignon.