Cork features: what no technology has been able to achieve


There are several cork features that no alternative technology or closures, such as screw caps, glass closures or synthetic closures, have been able to surpass.

In fact, there are several problems associated with the use of these types of closures: premature oxidation, absorption and transmission of foreign aromas or tastes and the fact that these can also be a TCA source. Furthermore, while cork stoppers are ideal for sealing liquid and gas, artificial closures are incapable of sealing gas. This can open the way for wines or spirits to be contaminated with small volatile compounds in the bottle’s external environment.

Learn more about the unique cork features that these competing products have been unable to imitate or surpass.

Natural cork stopper resting on a cork oak trunk


  1. Straight from Mother Nature
  2. Features and Intrinsic Properties
  3. Structure and Chemical Composition
  4. Conclusion

1. Straight from Mother Nature

Cork is the bark of the cork oak tree, i.e. 100% natural plant tissue. Since the harvesting process does not damage the tree, obtaining this raw material has no negative environmental impact. As well as being 100% natural, cork also stands out for being totally reusable and recyclable.

Once extracted, cork can be used for a variety of purposes, from the production of stoppers to more innovative applications in the construction, automotive, aerospace and even fashion industries.

However, cork’s life cycle doesn’t end there. Used cork stoppers can be recycled by grinding and reintegrated into production or transformed into new products such as shoe soles, panelling and even fishing buoys.

It is therefore a sustainable material with endless possibilities.

Cork granulate, resulting from grinding cork stoppers, ready for reintegration into production

2. Features and Intrinsic Properties

There are several cork features that make it a unique material:


Cork is a material notable for its exceptional lightness, derived from its composition. More than 50% of its volume is made up of air, which gives it a density of just 0.16 grams per cubic centimetre. This means that cork is around twice as light as wood and five times lighter than steel. A plank of cork, for example, contains around 60 per cent gaseous elements, which explains its extraordinary lightness.

Impermeability to liquids and gases

Cork is a material unrivalled for its impermeability to liquids and gases. This is due to the presence of suberin and cerin in its cells, which create a natural barrier against the entry of any substance.

Resistance to humidity also guarantees cork’s longevity, allowing it to resist ageing without deteriorating. It is therefore the ideal material for various applications where durability is essential.

Elasticity and compressibility

This natural material can be compressed to about half its width without losing flexibility. When released from the pressure, the cork returns to its original shape and volume.

This flexibility is provided by cork’s watertight cells, which contain a gas mixture like air, allowing cork to adapt to different conditions without suffering damage. The fact that it doesn’t increase in volume when compressed on one side makes it ideal for sealing and insulating.

On the other hand, cork’s elasticity guarantees resistance to variations in temperature and pressure. This means that cork can be used in extreme environments without losing its properties.

Antistatic and hypoallergenic

Cork is a naturally hypoallergenic material, which means that it does not contribute to the development of allergies. This is because cork does not absorb dust, one of the main agents causing respiratory allergies.

Resistance to friction

Cork has a unique cellular structure, similar to a honeycomb, which makes it extremely resistant to wear and tear. This structure gives cork the ability to absorb impacts and friction without suffering damage, unlike other hard surfaces, managing to withstand intense use without losing its properties.

Capsulated stopper resting on a cork oak branch

3. Structure and Chemical Composition

Cork cells have a pentagonal and hexagonal prism shape, a true work of art in miniature!

With sizes varying between 10 and 50 micrometres (thousandths of a millimetre), these cells are organised in a honeycomb complex.

Each cubic centimetre of cork contains around 40 million cells. A single cork stopper, for example, is made up of approximately 800 million cells, a veritable microscopic universe.

In terms of chemical composition, cork is made up of the following elements:

  1. Suberin (45%)
  2. Lignin (27%)
  3. Polysaccharides (12%)
  4. Ceroids (6%)
  5. Tannins (6%)

Suberin, the main component of cork, is a mixture of organic acids from which its cell walls are formed, preventing the passage of water and gases. Its properties are remarkable because it is practically infusible, insoluble in water, alcohol, ether, chloroform, etc.

Thanks to this aggregate of small cushions, cork is unusually compressible. At the same time, the suberin’s impermeability makes the cork cell walls airtight. No gas can escape, which is why cork is so elastic and its thermal conductivity is so poor.

Tray with several natural cork stoppers

4. Conclusion

In short, cork stands out as a natural, sustainable material with unique properties that make it unbeatable. Its lightness, impermeability, elasticity, resistance to wear and hypoallergenic properties make it the best choice as a closure for alcoholic drinks.

Unlike alternative closures, cork guarantees the preservation of the product, preventing premature oxidation and contamination with external compounds. Its intrinsic characteristics, like the presence of suberin, also give it unique properties that cannot be replicated by artificial materials or technologies.

Source: APCOR

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