There has been a great deal written about the use of natural cork vs. screwcaps in the wine blogosphere lately – mostly by folks who only have the experience of pulling them out or twisting them off. Many people who come to Bedell ask me the question – “What’s the deal with screwcaps?” Others are concerned about cork and wonder about the environmental aspects of using them to bottle wine. Some people wonder whether or not the world’s supply of cork is running out and if the cork trees are killed outright when they harvest the bark. Not to worry - that’s why I’m here to try and clean up some of the confusion in the greater wine world! Here’s a quick little primer on screwcaps and corks. Cork has been used to seal containers of wine since the second century A.D. The Romans (of course) used it for sealing amphora, making shoes, fishing floats and even insulation for their beehives. It wasn’t until the 16th century when it became common for corks to be used as a closure for glass bottles. By the mid 17th century, most of the wine industry was using natural cork.
Cork is produced from a species of oak called Quercus suber, which is native to the southern Mediterranean region of Europe and northwest Africa. The tree forms a thick, rugged bark that can be harvested every 9 to 12 years to produce cork. The harvesting of cork does not harm the tree; in fact, no trees are cut down during the harvesting process. This makes natural cork a renewable resource that provides an agricultural economy for many Mediterranean countries that cover almost 2.3 million hectares of forested land. Portugal in particular has been the leader in the sustainable development of the industry, implementing important reforestation projects - the current rate of reforestation being estimated at 10,000 hectares per year. This keeps many thousands of families employed in agriculture and provides an important ecological benefit to the region as well as to the rest of the world. Most would agree that the more land we can keep under trees the better off all of us will be. In my opinion this makes natural cork the most sustainable closure I can use - something which is very important to me.
Screwcaps were developed by the French company La Bouchage Mecanique in 1964 at the request of Peter Wall, Production Director of the Australian Yalumba winery. They became commercialized in the 1970s but have recently come back into fashion as the “hip” closure of choice, especially for younger consumers. The use of screwcaps in the wine industry is a direct result of the increased incidence of wines contaminated by 2,4,6-Trichloroanisole (otherwise known as TCA) which can be found on some corks. TCA is usually produced when naturally occurring airborne fungi and/or bacteria are presented with chlorinated phenolic compounds, which they then convert into chlorinated anisole derivatives. (ok the chemistry part of this class is over now…)
Older methods of cork manufacture often utilized chlorine as part of the washing process – something which is obviously no longer used. TCA taint can range from the smell of musty cardboard and dank basement to a subtle decrease in the wine’s aroma and flavor. It’s what happens when the wine is called “corked” - the biggest reason why wines are returned in restaurants. A lot of wine has been spoiled by TCA contamination over the years and the development and use of the screwcap was promoted as a way to decrease this problem. Some are now saying that screwcaps go so far as to guarantee a higher level of quality wine in the bottle. But I say - not so fast…
In my opinion, screwcaps do not guarantee a higher level of quality any more or less than corks do. The producer, vineyard, and climate as well as the passion and dedication of ownership, vineyard management and the winemaking team are what makes for quality wine. A wine that is insipid, uninteresting or flawed will remain that way regardless of the closure. What screwcaps will do is reduce the chance that a bottle will be spoiled by TCA. This is a very good thing, however it is also well documented that TCA can contaminate wines in the cellar prior to bottling as well. As screwcaps become more widely used we are already seeing some of the other potential problems associated with them - the instance of sulfide production in the bottle and the more recent studies showing that some of the plastics used in the liners of the caps may absorb aroma and/or flavors over a long period of time. As with most things in life, nothing is perfect.
What natural cork does do (something that scewcaps cannot do) is allow a small amount of controlled oxidation – microscopic exchanges of oxygen that enter the bottle and helps the wine age gracefully. This is particularly necessary in age worthy red wines which need this low level of oxidation in order to soften and become more complex with age. So far, screwcaps have failed this test of time.
What is most important in all this sturm und drang over wine closures is that an exciting new cork technology is being developed which is leading to a golden age of quality corks. During the past few years I've seen a huge increase in cork quality and a dramatic decrease in the incidence of “corked” wines. No doubt the market pressure from screwcaps and synthetic closures have forced the cork producers to raise their game and improve their product. Cork companies are now more adept than ever at removing potential problems from production using techniques such as steam and UV light treatments to reduce and sometimes eliminate the potential for TCA contamination. The bottom line is we are now using a higher quality cork than ever before and I expect the science around this issue to get even better as time goes on.
Yes you guessed it - I am a natural cork devotee - but my main point here is that there is no perfect closure. Wine continues to age and develop at some level no matter how we package it. Regardless of the closure, the finest wines will be made from the best and most dedicated producers. For me, I can’t quit the sound of a cork popping out of a bottle. It’s a sound many of us have grown to know and enjoy – a sound that indicates a special occasion, a celebration or a historic accomplishment. But most of all, it’s the sound of love and romance. It’s a sound heard over many generations – one that hasn’t changed in hundreds of years – that signals a special moment is at hand.
Sustainable, biodegradable, renewable, traditional, ecological, enduring, dependable and romantic – there’s lots of reasons to celebrate the new and improved cork. These are the reasons why as a winemaker, I choose to only bottle our wines with natural cork. So the next time you pull one out of a bottle, celebrate another one of nature’s great gifts to humankind – the wonderful and extraordinary natural cork!