THE PROPERTIES OF CORK
Used since Antiquity as a closure for Greek amphorae,cork has specific properties which make it a unique material.Well-known for its elasticity,it also boasts other,very worthwhile physical characteristics that make it an ally for wine maturation.
Elasticity,cork’s major advantage
Cork is extremely shock- and pressure-resistant due to its high level of elasticity.It therefore has a great ability to return to its original shape,just like a memory foam cushion.
When pressure is exerted,even strongly,it instantly resumes 85% of its initial volume.
This elasticity is highly sought-after in the bottling sector but also in the building industry.
The 10 other properties of cork worth knowing
Although cork’s elasticity is its best-known quality,as a raw material it has other properties that are just as interesting.
Natural, Versatile, Sustainable,Cork is such a perfect raw material that no industrial, laboratory or technological process has yet been able to emulate its characteristics.
More than 50% of the volume of cork is air, which means that it is very light, weighing just 0.16 grams per cubic centimetre, and can float.
Elastic, compressible and resilient
Cork is the only solid which when compressed on one side, does not increase in volume on the other. In addition, it has an “elastic memory” which enables it to adapt to variations in temperature and pressure. This characteristic is due to the gaseous mixture between each cell, which allows it to be compressed to around half its thickness, and subsequently decompressed, returning to its original shape.
Thanks to the suberin and ceroids contained in the cell walls, cork is impermeable to liquids and gases. Its resistance to moisture enables it to age without deteriorating. Cork is one of the best type of stoppers available in the market.
Thermal, acoustic and anti-vibration insulation
Cork has low conductivity of heat, sound and vibration. This is because the gaseous components contained in cork are enclosed in small impermeable compartments, and isolated from each other.
Hypoallergenic, antistatic and odour-free
Cork offers protection against allergies because it does not absorb dust, and therefore prevents the appearance of dust mites, and therefore the odour of its aromatic compounds is not intrusive.
Resistant to friction
Cork is very comfortable because its cells are formed from microscopic gas pads. This characteristic gives cork the ability to absorb shock and thereby relieve pressure on the foot, protecting joints and safeguarding the spine.
The slow combustibility of cork makes it a natural fire retardant. Cork is therefore a natural barrier against fires. Cork burns without a flame and does not emit toxic gases during its combustion.
Renewable, recyclable and reusable
Cork is a renewable, recyclable and reusable raw material.
As a natural product, cork is 100% biodegradable.
Cork dust may be used as biomass, as a source of neutral energy in terms of CO2 emissions.
Soft to the touch
Cork is very soft to the touch, with a very unique odour, that is not intrusive and is slightly sweet. With a normal temperature very close to that of the human body, cork emits a sense of comfort that is hard to replicate with any other material.
The properties of cork of benefit to wine
Its elasticity,but also all of cork’s other properties,make it an excellent material for producing closures for bottles of wine.
Cork is watertight,allowing the closure to properly seal the bottle and avoid any wine spillage.But it does allow small of amounts of air through.
And oxygen is a crucial component for wine to mature well in the bottle.
When temperature and hygrometry are optimal,the porosity of cork allows the wine to breathe and mature harmoniously.
Also,cork closures exert strong and consistent pressure on the surface of the bottleneck and can therefore compensate for any imperfections in the glass bottle.This is also what makes each cork closure unique.
Cork’s properties make it a unique material,which explains why it is so successful.The cork closure is still extremely sought-after in the wine industry and offers the perfect combination of watertight seal and the required oxygenation of the wine to allow it to breathe and mature.