Many of you have probably noticed the use of cork to seal a bottle of wine is declining rapidly. More and more producers tend to lean towards the Stelvin closure (Stelvin is registered trademark of Alcan Packaging which is the largest manufacturer of screw tops) and other materials to seal the deal. From synthetic (basically plastic) cork to the Vino-Lok (a glass closure device) you never know what is going to be under the foil.
One of the main reasons we are seeing new methods for sealing a bottle of wine is cost, in a few different ways. The first is the price of cork. Cork comes from the bark of the cork oak tree which mainly grows in places like Portugal, Spain, Algeria, Tunisia, Morocco and Sardinia. Most of the cork we see here in American comes from Portugal. The first round of corks cannot be taken from the bark until the tree is twenty five years old. After the bark is taken off of the tree for the first time it cannot be taken again for about ten years, this can happen fifteen times until the tree is cut down and made in to Dunder-Mifflin Paper; sad. It is a labor intensive job to strip the bark and mold it in to the cork's appropriate shape. This process is time consuming and after all of that the bark has to dry for about year after it is taken from the tree before it can be cut in to corks used to seal wine.
In the mid 1900's cork was on the fritz until the Portuguese government took action and commissioned the restoration and replanting of the resource. With all of the efforts to keep up with the demand, unfortunately there is just not enough to go around. The number of wineries all over the world grows every day. To give you an idea of growth taking place, somewhere in the realm of 800 wineries occupied California in 1990, today there are over 2600. The demand domestically alone has contributed to a lack of corks, not to mention globally. So with these figures we see why it is important to develop new ways to seal a bottle.
The first and most criticized method is the screw top or more romantically the Stelvin closure. Today it does not have the same stigma as it did when it closed you favorite flavor of Boone's Farm in college. Some great wines use the Stelvin closure. Some regions have adopted it as their primary closure method. For example in 2000 a group of wineries in Clare Valley, Australia banded together to make it policy that they close their wines with the screw cap. This in turn lead to a number of producers to further investigate the screw top method. For example in 2001 in New Zealand only 1% of wine producers used a screw cap, but by 2008 more than 90% were using it. In addition more than 60% of all of the wine made in Australia uses the screw top closure.
The Stelvin method of closing wines was first developed in the late 1960's, it did not become fully commercialized until the 1970's when a French company, now Alcan, mass produced it. It was developed in 1964 by the Production Direct of Australia's Yalumba winery, Peter Wall. His prototype used a Stelcap/cork combination. He closed the wine with cork and then put a long skirted screw cap over the top. This patten was in turn sold and mass produced. Initially the cap did not have a very good coat to separate the wine from the aluminum leaving the product tasting metallic. The stigma and the ineffectiveness lead to the abandonment of the screw top in the 70's.
To test the longevity of the process the esteemed Haut-Brion (prestigious Bordeaux producer) sealed some of it's 1971/72 vintage with the Stelvin closure. In 1978 they opened it up and found it similar to the cork sealed wines. They found that the fruit was more vibrant and almost better preserved. Both a good and bad thing. The fruit being preserved is a good thing for wines produced today that are meant to be drank young when they are bright and colorful with sweet fruit flavors and youthful aromas. However trace amount of oxidation is appropriate for aging. The same cork that can be blamed for the cause of a wine going bad can be praised for making a wine better. The natural amount of trace and I mean trace oxygen that a cork can provide can add character and development to a wine.
Also, as you can imagine screw tops are less expensive, but that does not mean that the juice inside is. In 2005 one of Burgundy's best-known producers Jean-Claude Boisset closed some of their wines with a screw top, including a $125 bottle of Chambertin Grand Cru. In 2008 almost a third of their 200,000+ bottle production used screw caps.
Another advantage to the Stelvin closure is that it is idiot proof. What I mean by this is that the screw top has the ability to compensate for improper storage. A cork requires wine contact in order to keep the cork moist so it does not dry up and allow air to enter the bottle. This is the reason a bottle is traditionally stored on its side. A screw top on the other hand can be stored in a variety of position, upright for example, with out the fear of the wine being tainted. Also, a cork will expand and contract depending on the elements. For example, a cellar that does not have enough humidity can cause the cork to dry up and let air in to the bottle oxidizing the bottle (ultimately turning it in to vinegar).
Another popular closure method is the use of a synthetic cork. These are found on a number of bottles and are much more cost effective for the producer and, by result, the consumer. This gives that same pop sound as the cork without the faults. Cork can some times have a bacteria in it called trichloranisole (TCA). Don't worry, it is not going to kill you. It is found in two to five percent of all cork produced stoppers. It is a bacteria that through contact with the juice leaves the wine smelling of wet cardboard. This can be costly for the producer because usually this comes back to them and they have to replace it. However with the synthetic stopper the wine is not threatened by this. A synthetic cork also does not expand and contract like a cork made from bark does. However the synthetic closures are made from a plastic material that is not biodegradable and are seldom recycled. They are also sometimes a real pain in the side to get out of the bottle because they get stuck in there.
One of the new and exciting types of wine sealant is the Vino-Lok. Most commonly I see them in Rieslings from Germany and wines from Austria. It is a glass nipple looking device with a small rubber seal. They are mainly used in wines meant to be drank young and will not benefit from any form of trace oxygen. The Vino-Lok helps preserve the freshness and youthfulness of a wine. I really like these types of closure systems, although when I approach a table and peal back the foil I am usually surprised and I sometimes stumble through the service steps.
The last type of closure method you may see is Agglomerate cork. This is waste cork particles, basically the ones that didn't make it to "the show", that go through a secondary cork production process. The particles are washed and dried and then are sent through a grinder to break them up. They are then pressed and put in to a machine that heats them up to mold them in to a big sheet, from which the cork shape will later be cut. Often an adhesive is used to bind the particles together. This process is still fallible because there is a risk of TCA, also known as cork taint.
As we can see there is no perfect answer for how to seal a bottle. With screw tops, synthetics, and the Vino-Lok we eliminate the risk of cork taint and oxidation, but we loose the romance and positive aging capabilities that we have with a cork. The most important advice I can give you is do not turn your nose up at the screw top, it is great for the price of wine and does wonders for the environment. Of the seven billion or so wine bottles sealed every year the number using screw caps will reach close to three billion this year. I would guess that over the next five years we will see virtually all bottles under $12 retail move to a screw top. Then again don't count cork out, it is trying to make a come back. The retailer Whole Foods is placing cork recycling bins at the ends of some their aisles to encourage people to bring in their spent corks so they can be reused.
Whatever the case remember it is what on the inside that counts. I love the romance of the unknown with cork. I like the craft I must apply in removing a cork from a bottle of 1985 Dow Vintage Port. But I also appreciate screw tops because I never have to wonder when I get to a table if the wine has cork taint. And I like them because no matter where I am, I don't need my wine key to open the bottle.
Cru Wine Specialists