Cork versus screw top

There is certainly more than one way to close a bottle of wine. Bristol Bar & Grille master sommelier Scott Harper is often asked if he prefers wine with a cork versus screw top. Here he breaks down the advantages and disadvantages to the variety of closures of a bottle of wine.

Cork versus screw top

Gone or at least mostly gone are the days when a bottle of wine sealed with a screw cap was considered inexpensive plunk. Now wines from every country, every price level, and every quality level are sealed with a variety of closures, not just cork.

What is a cork?Cork versus screw top

Natural Cork is the name given to the bark of the Cork Oak tree. This bark is stripped off to make wine bottle corks. A common fallacy is that the tree dies after the cork is harvested. In actuality the average life of a cork tree is between 170 and 200 years. Furthermore, after the bark is harvested it regenerates and can be harvested about every nine years. With all factors included, a cork oak tree will yield around 17 harvests. The majority of the world’s cork comes from Portugal, with Algeria, Spain, Morocco, France, Italy, and Tunisia making up the balance. Cork has been used since the 1700s to seal bottles of wine. Corks are biodegradable and recyclable.

What is an alternative closure?

Most screw caps are aluminum closures that thread on to the neck of a bottle. Screw caps are the most used alternative closures and have taken off in the last 10 years. Crown caps are the same closures you see on beer bottles and are used in the sparkling wine industry for the closure during the secondary fermentation, capturing the coveted bubbles. Vino-Seal or Vino-Lok are two of the names used for a closer that makes an airtight seal. These closures remind you of a liquor bottle closure, but instead of being made from cork and plastic, they are made of glass or acrylic. Synthetic corks are made from plastic and in the same shape/size of natural corks. These represent the vast majority of today’s alternative closures and most are recyclable.

Issues with natural corks:

When using a cork versus screw top, a bottle of wine can be tainted by a cork. It was found that if a fungus was present on a cork and the cork was cleaned with a chlorine solution, those two elements could come together and create 2,4,6-Trichloroanisole (TCA). Many people call a TCA-tainted wine ‘corked’ or having cork taint. The result of TCA is a wine with the smell and flavor of must, moldy newspaper, wet dog, or old, wet cardboard. TCA can also mute and reduce the aromas and flavors of wine. It takes away the characteristics the winemaker fought so hard to achieve. Cork producers have eliminated the use of chlorine and have replaced it with hydrogen peroxide, but corks with TCA still exist. TCA is also able to be transferred into the wine from barrels in the wine making process, but according to the cork industry they have dramatically reduced the incidents of TCA. Oother sources state between 1% to 15% of natural closed wines have TCA. While TCA does not pose any health risk, it certainly poses a risk to wine drinking and could be construed as a winery’s bad wine instead of a flaw from the cork.

Cork versus screw topIssues with alternative closures:

While alternative closures are all but a guarantee of no TCA, most consumers do not understand TCA is the largest reason for the alternative closure. Many still think it is because it is more affordable or because it is an inexpensive wine making technique. The consumer feels uncomfortable on special occasions opening an alternative closure as they are at risk of seeming cheap. Occasionally, screw caps get stuck and require real strength to open. Some other closures simply catch consumers unaware of how to open the bottle. Lastly, what will be the long-term effects of aging a fine wine for 30 years with an unproven alternative closure?

Benefits of Natural Cork:

Closes a bottle with Natural Cork versus screw top is a traditional, if not a formal way to close and therefore open a bottle of wine without it appearing inexpensive or cheap. Natural Cork has a proven track record for long term aging so there is no fear (other than TCA) of what may happen to an aged wine. Cork is biodegradable, recyclable, and a renewable natural resource.

Benefits of alternative closures:

The most important benefit to alternative closures is the guarantee that there is no cork taint because there is no cork. TCA is unlikely, but still possible due to other issues at the winery. Screw caps are easier to open and do not require any special tools. Other alternative closures use very simple tools such as a bottle opener. This lightens the formality and ease of appreciating a bottle of wine. Most alternative closures are recyclable. I personally like alternative closures, but I also appreciate the time honored tradition of natural corks. I say forget cork versus screw top and make room for both!