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10 reasons why you should use natural cork stoppers for your sparkling wine: expert scientists explain

Razones importantes para usar corcho natural en tu vino espumoso - TESA CORK
Fecha de publicación: 10 de November de 2021

Today, we’re talking to Anna Oliveras, the head of the chemistry division at the Catalan Cork Institute (ICSuro).

Anna has a BSc in chemistry from the University of Girona and boasts over 15 years’ experience in the cork sector, in which she has carried out numerous research and innovation projects for the industry.

She currently works at ICSuro, where she continues to conduct new research and advisory projects for this sector.

The Catalan Cork Institute has been working for years to develop and improve the cork industry, while also carrying out educational and instructional activities to raise awareness of the importance of using this natural and sustainable material.

Today they are going to give us 10 compelling reasons why natural cork should be used as the closure system for our wines:

Reason 1 – Very similar characteristics to wine 

One of the aspects that sparks most interest and study is how the cork contributes to the wine, in particular the aromas it might add.

Over the years, numerous sensory analyses of wines bottled with cork have been carried out, in which a large majority of experts agree that wines stoppered with cork age like no other, and that it is the cork that improves the qualities of the wine with the right aromas.

Creating universal standards or parameters to analyze these subtle aromas and their origin is very complex, if not impossible. And since there is no such thing as an absolutely neutral material, it makes sense to look for materials that can provide natural notes to improve the end organoleptic properties.

This is where cork is instrumental, as experts consider the notes it provides—as is the case with oak barrels—to be very positive and that they add body and personality to the resulting sparkling wine.

Reason 2 – The best oxygenation in the industry

One of the biggest headaches for developers of stoppers made with other types of materials is trying to achieve the same oxygenation volume as natural cork, which has proven to be optimal.

Natural cork stoppers tend to offer perfect micro-oxygenation to the wine once it is bottled, after which a smoother transpiration occurs that prolongs the aging of the wine, preserving its essence for years and helping it reach optimum maturity.

Materials such as plastic and silicone can cause wine to over-oxygenate and oxygenate prematurely. For this reason, these types of closures are only recommended for affordable wines intended to be enjoyed soon.

Screw caps, popular in markets such as Australia and the US, are a very practical type of closure as they are easy to open, but they are also the source of many complaints due to oxidized aromas being found in the wine.

Only higher end screw caps have been proven to have balanced oxygenation levels, but these are often priced similarly to cork, without offering the other advantages that cork brings to the wine.

Reason 3 – Unmatched physical qualities

Cork is made up of a structure of microscopic hexagons that act like microcapsules of air. Its structure closely resembles that of a honeycomb, and it is this special shape that gives it many properties, such as elasticity, adaptability, compressibility, insulating capacity, and lightness.

This complex microscopic structure offers so many benefits that numerous alternative materials industries have tried to replicate it artificially without success.

Reason 4 – Impermeability

Cork has been proven to be totally impermeable thanks to the waxy compounds and suberin present in its composition.

Under stable temperature and humidity conditions, cork stoppers have proven to be effective over long periods of time, up to 100 years or longer, providing complete protection against the leakage of wine or carbon dioxide gases in the case of sparkling wine.

Reason 5 – Leak Tightness

Despite being completely sealed against leakage or liquid ingress, there is much debate about the filtration of gases.

Today, it is understood that although cork is capable of retaining the carbon dioxide gas of sparkling wines inside the bottle, it also allows the slow release of oxygen that comes from the buildup of air within the micro-cells of the cork itself (honeycomb structure). This ensures optimum oxygenation and appropriate aging in the bottle over long periods of time.

Further studies are currently underway to obtain more comprehensive information on oxygen transmission in sparkling wine cork stoppers.

Reason 6 – Elasticity

Thanks to its honeycomb structure and the large amount of air within it, cork possesses unique elasticity and adaptability characteristics.

This is something that makes it so ideal as a stopper material, as it perfectly adapts to the shape of the bottleneck, with the ability to contour and mold to any deformations and ensure the wine remains sealed for years to come.

Reason 7 – An Industry safe from TCA

One of the main possible downsides to cork is the presence of the compound TCA in stoppers.

Thanks to major investment of resources across the cork industry to provide a completely safe product, the incidence of TCA has decreased considerably.

Today, any certified supplier of cork stoppers uses state-of-the-art analysis systems such as gas chromatography at its facilities, employs technical personnel specialized in analysis, and implements highly effective selection and sterilization systems in its production line.

Such is the extent of the cork industry’s efforts in this area that it is now even more accurate than the pharmaceutical industry in detecting compounds at very low concentration levels.

This is why cork stoppers are today the most analyzed and safest elements in the wine industry. Only manufacturer malpractice or wine producers neglecting to follow supplier instructions could lead to TCA contamination.

Reason 8 – Carbon footprint

One of the biggest overall challenges facing industry today is the climate impact of global warming. In the wine industry, it is causing changes to vineyards and generating unforeseen economic investments for producers.

The cork industry is carbon-negative, which means that it captures more CO₂ than it emits into the atmosphere.

This is excellent news and something to be taken into account by producers and consumers, as we find ourselves at a true environmental tipping point, and it is now more important than ever to embrace green industries, sustainable materials and recyclable products, such as the cork industry.

Reason 9 – Sustainability and biodiversity

Cork is a 100% natural raw material harvested from the cork oak tree without the need for felling or significant damage.

Cork oak forests therefore produce tons of cork annually without emitting pollution or suffering damage. This makes cork a sustainable and eco-friendly material that does not cause any harm to the planet in order to be produced.

Cork oak forests contribute to the preservation of biodiversity and survival of many native species of fauna, some of which are endangered, such as the Iberian lynx—the feline species at most risk of extinction in the world. They also act as carbon sinks, are highly resistant to fire, contribute to sustainable forestry, offer a natural, recyclable and renewable product such as cork, contribute to fostering the circular economy, and serve as a barrier against desertification.

Reason 10 – Fire prevention

Cork oak forests are inherently Mediterranean, which means they are adapted to dry summers and possible forest fires thanks to the outer bark of the trees.

Cork is a natural flame-retardant layer, so when there is a fire, the tree only suffers superficial external burns, protecting the interior and keeping the plant alive. Unlike other types of forests, a burned cork oak forest regenerates a few years after the fire.

Contact with TESA CORK

As you can see, cork not only boasts the ideal characteristics to seal bottles for years preserving the essence of the wine, it also adds highly valued aromas, and thanks to industry breakthroughs, TCA levels are imperceptible and safe.

But most important of all, cork is the only material that is not just 100% natural, but that also helps capture CO2 from the planet’s atmosphere, reducing the effects of global warming.

If you would like more information, please get in touch with us. We would be delighted to help you.