by Tom Banach
In Part 1 we gave a brief history of cork. Now we will compare two types of closures for your wine—natural cork and synthetic cork.
Let's start with synthetic corks. The sole reason that synthetics are popular today is because of the lack of the natural cork industry to correct a large TCA (2,4,6-trichloroanisole, a byproduct of mold) problem that occurred years ago. Some wineries were losing up to 15% of their vintages due to TCA. Synthetic corks easily solved the problem as TCA is non-existent in them. The cork industry finally came around and spent millions of dollars to correct the problem; but by then, synthetic use had flourished and has not looked back since.
Other benefits of synthetic are that the corks do not break and crumbs from the corks do not fall into the wine. They do not have irregularities like natural corks so you can always get a proper seal. This cork is an excellent choice for the wines you will drink young. The price can be easily a third of that of quality natural cork.
On the negative sides we find that you do not want to use it to bottle your fine Bordeaux that you intend on opening 25 years from now. You will also need a floor corker to insert them as it is nearly impossible to do with a hand model.
There are many brands, but the one commonly used by club members is Nomacorc brand. Nomacorc closures are made with a foam core that is breathable and has an outer skin. The core allows oxygen to transfer through it and the skin gives it a consistent seal. Nomacorc Classic will give your wines a couple of years of protection and the next generation, the Nomacorc Classic+, is touting up to four years of protection.
There are nine grades of natural cork. They are, rating highest grade to lowest: Flor, Extra, Superior, 1st, 2nd, 3rd, 4th, Agglomerated and Colmated. Flor are not only the best, but are also the rarest. Only one in every 5,000 corks gets this grading. They have the fewest pits and are much denser. These are used by the finest wineries.
Near the other end of grading are Agglomerated. These are made from granulated cork; basically the waste from the manufacturer. The granules are mixed with a food-grade glue and are molded into corks. These corks are rated for wine not to exceed 12 months in age.
As mentioned, the industry spent millions of dollars solving the TCA issue. A large producer, Norcor of Portugal, took a number of steps to nearly eliminate this problem. Norcor produces 150 million corks annually, and all of their corks are treated using ozone, ethanol and sulphur dioxide, processes that have been proven effective against TCA. The corks are then peroxide washed for sterility and the surfaces treated with silicon and paraffin for easy corking and a better seal. At packaging, the corks are sealed in a bag filled with SO2. All corks go through four in-house laboratories that do physical, chemical, microbiological and sensory analyses.
These are the corks to use for bottling for extended shelf life. What is important to note is that natural corks should not be wet or heated at corking time.
Personally, I use Nomacorc for the wines I drink young and 1st grade natural cork for all others. Nomacorcs can be obtained from many locations, and Norcor natural corks are available online at St. Pat's of Texas.
Only buy quality corks from a reputable vendor. How much is it worth to protect your vintage?
Resources for this article came from www.nomacorc.com and www.stpats.com.