April 27, 2015

Types of Wine Corks

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Learn About the 5 Main Types of Wine Corks

Image credit: Hope Valley Wines

Now a days, a wider variety of types of wine corks and bottle stoppers exist to preserve wine. Some wine makers, especially those who mass produce value wines, are using metal twist off caps instead of corks. While cork type (or lack there of) in some ways affects wine flavor over time, as well as our perception of taste, it’s also critical in protecting wines as they age. Some types of wine corks are more reliable than others.

Let’s take a look at the main types of wine corks below…

 The Lowdown on Wine Corks

While cork has a multitude of uses, the wine industry is no doubt the biggest consumer of natural corks world-wide. Not all corks are created equal, and their primary purpose is to preserve the wine for long term storage.

Natural corks have been used for centuries due to the elasticity of their cellular structure. Cork is malleable to a point, with the ability to both contract and expand to a certain degree, creating an almost air tight seal in a bottle of wine. I say ”almost air tight” because some air is able to pass through natural cork, since microscopically there are gaps within the cork structure. This can be either beneficial or detrimental to a wine dependent upon the type of wine being stored.  Some wines age better with minute air exposure over periods of time, while others keep much better when exposed to no air during storage.

Both the type and size of cork used to store a wine is determined by the type of wine, the amount of pressure contained within the bottle, and the diameter of the bottle neck.

 Wine Cork Fact: Did you know that Portugal makes over 50% of corks used world wide? Spain comes in second at about 30%.

Natural Wine Cork Types

Image credit: Corklink

 Types of Wine Corks

Natural Wine Corks

“Natural Cork” is an umbrella term for different grades and styles of cork made from natural cork tree bark.  These corks are 100% natural, and can either be one-piece cut from one sheet of cork bark, multi-piece, where at least two pieces of cork are glued together, or colmated, where the tiny holes within a natural cork are filled in with cork dust and glue.

  • One Piece natural corks are ideal for the aging of wine long-term.  They very naturally expand and remain strong over long periods of time.  When removed from a bottle of wine, a one-piece natural cork will expand to 85% of its original size almost instantly, while regaining the rest of its original composure within the next 24 hour period.
  • Multi-Piece corks work well with wines that don”t need to be aged for long periods.  These corks are often made with cork bark “scraps,” cut from cork bark areas that weren”t very thick to begin with.
  • Colmated corks are the middle ground for aging.  Because a large portion of the tiny holes in the cork have been filled in, only small amounts of air are able to reach the wine.  These corks are typically used for wines that shouldn’t be aged for more than 3 years.
Agglomerated Types of Wine Corks

Image credit: CorkStopper Portugal

Agglomerated Wine Corks

Think of agglomerated corks as hybrids.  These are comprised of both natural cork bark material and synthetic parts making for a relatively dense cork composition. They are typically on the cheaper side, and made primarily of natural cork bark scraps, cork dust and glue.  I have had some poor experiences with agglomerated corks when trying wines over 2 years old.  Bare this in mind if you own or plan on buying wines that utilize agglomerated corks — for best results they should be consumed within the first year.

Twin Top Wine Cork Types

Agglomerated “Twin Top” Wine Corks with Natural Cork Ends

Also designated the “double disc,” these corks are a type of technical cork and are made up of two natural cork discs on either end, with the ”meat” or middle of the cork being completely agglomerated.  These vary in quality, and are ideal for storing wines that require medium aging, since only small amounts of air can reach the wine.

 

Synthetic Wine Corks

Synthetic wine corks have only begun to be used on a large scale within the wine industry.  They are most commonly made from oil based plastic, while certain synthetic cork manufacturers are also experimenting with utilizing plant based polymers from corn and sugar cane.

Synthetic Types of Wine CorkSynthetic corks can be advantageous to wine makers looking to achieve a scientific degree of oxygen transfer.  Since these materials can be crafted are various densities and from various materials, they can have set air transfer rates.  At this point in time, it seems there are more positives than there are negatives to synthetic corks.

Positives

  • Synthetic corks will last for long periods of time.  Because the material used to make synthetic cork is not natural, wines will never be at risk of attaining cork taint.
  • Wine can be stored standing up, as opposed to being laid down, since they don’t require the moisture from the wine to keep up cork integrity.
  • Fixed and predictable oxygen transfer rates
  • Tight seal, anti-bacterial

Negatives

  • Since most synthetic cork material is comprised of petroleum based plastic, some argue that it adds a chemical odor and or flavor to the wine being stored.

Last but not least – it”s not a wine cork but it serves a similar function…

Metal Twist Off Wine Screw Caps Types of Wine Corks

Image credit: Gavinwine.com

Metal Twist Off Screw Caps

Twist off wine screw caps are being utilized more in New World wine regions, rather than old, where tradition is less of an issue.  These corks, for the most part achieve the purpose of storing a wine for medium to long term aging, as well as up-right.  The biggest advantage of using a screw cap over a natural cork is that there is NO risk of cork taint over time.

Additional sources and photo credits: Cecchi Winery, WikipediaWine Folly, Chicandjo, Amorincork, and Decanter.com.

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2 Comments

  • Actually there is a lot of interest in screw caps, even by the most famous winemakers such as Chateau Margaux http://www.wsj.com/articles/SB10001424052970203918304577241182575505006

    • Yes, we’ve noticed that a large number of producers are experimenting with these. It’s no surprise that those in Bordeaux find it both appealing (since many of these winemakers aim to age their wines for many, many years and cork taint is a real issue), and detrimental to tradition. I think ultimately it will become a question of does it go against the traditional grain too much, and even if it does, is it worth sacrificing tradition to ensure ALL of their end wine products are at no risk of cork taint. It would be a pretty big deal, especially for a Chateau as famous as Margaux.

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