Mankind has been using corks (or phelo in Greek) since the days of ancient Egypt, maintaining the quality of a wine even over a period of many years. Remnants of cork stoppers found in Egyptian tombs highlight just how far into the past cork usage goes and it’s usefulness.
Cork history includes use as buoys for ancient Mediterranean, fishing nets and boats. Ancient Greeks used cork in their sandals because it acts as a natural shock absorber. The Romans had plenty of uses for cork as well, including construction material, beehives and floatation devices. As for the raw material, cork trees or Quercus suber as commonly called the cork oak, thrive in the Mediterranean area such as Portugal, Algeria, Spain, Morocco, France, Italy and Tunisia. They live on average 200 years, but there are cork trees that are 500 years old and they grow up to 75 feet tall. The bark is stripped manually by expert harvesters in the months of May to August and it can be re-harvest after 9 to 12 years. A 200 years old cork tree can be harvested over 16 times its entire life. But what about its use in wine? Wine corks have been the preferred wine closure option for centuries and for good reason. The cork material enables wines to age without going bad. The porous material of wine cork enables tiny amounts of air to interact with the stored wine, helping it to age and transform in aroma and flavor. However, the elasticity of the cork seals the bottleneck by expanding and ensures all liquid is completely sealed within the bottle. The usage of corks in wine did not become common practice until the late 1600s. Prior to that, winemakers used glass as a sealer. Corked wine came into being when it became possible to create glass bottles of unvarying design. In recent years, a few other wine closure options have entered the market, however, traditional wine corks remain the most popular option for modern wine brands. Let’s dive into the multiform world of 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
These are ideal for the aging of wine long-term. They very naturally expand and remain strong over long periods. 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
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
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 can reach the wine. These corks are typically used for wines that shouldn’t be aged for more than 3 years.
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. We 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.
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 corks can be advantageous to winemakers 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, it seems there are more positives than there are negatives to synthetic corks.
Positives
Synthetic corks will last for long periods. 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, they also seal tight and they’ re 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.
Glass Stopper or Glass Cork
Glass stoppers are made of durable, high-quality glass that forms an airtight seal to preserve the wine’s freshness and flavor. They are often used for premium wines and spirits and can be easily removed and resealed. Glass stoppers are gaining popularity due to their sleek appearance, reusability and eco-friendly nature. However, they are still less common than the other types of wine closures mentioned previously.
Metal Twist Off Screw Caps
Twist off wine screw caps are being utilized more in New World wine regions like Australia or South Africa, rather than old, where tradition is less of an issue. These corks, for the most part, achieve the purpose of storing a bottle of 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. What’s your preference on cork sealings based on your experience?