Art of Cork - Wine Art Crafts By Daniel Kubini

Material

Cork is:

Tradition
Renewable
Sustainable
Green
Recyclable
Natural
Better

There's a reason the screw cap hasn't dominated the wine stopper industry: Cork still kicks the ass of stamped aluminum for the good stuff-and not just for nostalgia's sake. This is what keeps our evening libations from turning sour.

Cork is an unbeatable bottle stopper. It's compressed by machines, jabbed by wine keys, and assaulted by liquids, only to bounce back, close up the gaps, and continue to keep leftover wine at bay.

Cork has been doing the same job well for thousands of years. Ceramics with cork tops were tucked into Egyptian tombs, and the Greeks shoved the spongy wood in containers filled with wine and olive oil. But it wasn't until Dom Pérignon-perhaps you've heard of him-developed the process for Champagne production in the 18th century that the cork stopper got its big boozy break. At the time, French sparkling wines were plugged by plain old wooden pegs wrapped with olive oil-soaked hemp. This setup blew. No, really. The gas in wine kept popping the slick stoppers out. Without a proper stopper, wine was losing its sparkle and the appeal of Champagne was falling flat. So as a way to seal his beverage-and ultimately his legacy—Pérignon started a series of experiments to find a better way. When he landed upon cork, it wasn't just the bubbly producers that appreciated a more perfect fitting: The entire wine industry ended up adopting it up as the stopple standard.

Cork performs extremely well under pressure. With some nudging, cork can compress to half its size, without bulging out the other side or increasing its length. Ok, so there are a lot of things that can do that if you push them hard enough, but the key here is cork's resilience. Cork's insides look like a honeycomb filled with gas-89.7 percent gas, in fact-which makes it both light and buoyant. And the cells that make up the honeycomb are insanely stretchy. So the cells can stand to be squeezed tight—like by, say, the skinny neck of a wine bottle.

But cork doesn't collapse under the abuse. Although the gas in the cells is compressed and loses volume, it is always pushing back, which allows it to seal cabernets and champagnes.

While stuck, liquid's constant lapping doesn#39;t cause the cork to flinch. This wine stopping power is due to a coating made of a complex mixture of fatty acids and heavy organic alcohols called suberin inside the cork's cell walls. The suberin, plus tannins and a scarcity of albumenoids, leave it decay resistant and unfazed by moisture. In fact, the United Nations' Food and Agricultural Organization says that pieces of cork can stay submerged in liquid for centuries without rotting. Taken all together, these things make cork maybe the best seal in existence.

Here#39;s another way cork gives other caps the finger: If you're keeping wine in a cellar for a long time, a little bit of air does a body good. The reason is that wine contains a little bit of sulfur dioxide. But "without oxygen, that sulfur disintegrates and creates a smell like a struck match," says Vance Rose of cork producer Amorim Cork America. You do not want to swirl that around in your cup and sniff it. Cork adds air naturally by releasing a wee bit of its stored gas, maybe 3-4 milligrams. Screw caps are either hermetically sealed, leaving bottles with a potential sulfur problem, or they#39;ve been engineered to allow a little outside air in. While that little bit of air is good for the sulfur, but not good if it#39;s sucked from a wet cardboard or musty cellar. Cork#39;s gas release doesn#39;t come from the outside, so it doesn#39;t smell.

This means that when it is time to pop the top, both wine and cork come out unscathed-the wine appropriately aged and the cork looking almost like it always did. Even after years of abuse, "the cork doesn't lose any integrity in its cell structure," explains Rose. "It goes right back to its original form." The cork has always maintained this fine form so your Malbec can, too.

Properties Of Cork

There is no other material, either manmade or natural, with all the properties and characteristics that are unique to cork : light weight, rot resistant, compressible and recoverable, expandable, fire resistant in its natural state, impermeable, soft, and buoyant. Because of this unparallel combination of properties, cork raw material has a wide variety of applications. With its light-weight honeycomb structure and its flexible membrane, cork is the ideal material for products ranging from stoppers to floats, from floor and wall coverings to gasket material, from clothing to coasters.

Cork Characteristics

Lightness

Cork is light and will float. Beneficial for buoys, floats, fishing rod handles, level gauges. Light weight makes cork an excellent filler material for many products. Perfect for shoe insoles and soles.

Elasticity

The cellular membranes are flexible so that the cork can be fitted against the wall of a bottle under pressure (the airin the cork cells is compressed, reducing volume) and when released bounces back to its original form. Perfect as a stopper, perfect for floor tiles and wall tiles.

Impermeability

Cork does not rot due to the suberin which makes it impermeable to gases and liquids.
Combined with corks other characteristics it is the ideal material for bottle stoppers, gasket sealers, joint fillers, floor underlayment, and bulletin boards.

Low Conductivity

Gaseous elements in cork are sealed in tiny cell like compartments insulated and separated from each other. This provides for low conductivity to heat, sound and vibrations. One of the best insulating and acoustical capacities of all substances.

Resistance to Wear

The honeycomb structure of suberose surface gives cork a high friction coefficient and makes it very durable. It does not absorb dust and is fire resistant in its natural state. Ideal material for all building products, including floor and wall tiles, cork wallpaper, rolls, and sheets.

The worlds main cork oak forests are found in Portugal, Spain, southern France, Italy, and North Africa. It is the micro climate and soil types of these regions that allow cork oaks to grow and flourish and serve as the primary source of raw material for the cork industry. Today more then half of the worlds cork raw material comes from Portugal. Although cork trees are also grown in limited amounts in several other areas in the world, only cork harvested from the Mediterranean region is of a quality suitable enough for the production of natural wine corks. An interesting example of this restricted regional growth phenomena occurred in California, USA. Some years ago an American entrepreneur imported cork oak saplings from Portugal and planted them in various locations throughout the state. He felt that since the climate of California was similar to that of Portugal, the trees would grow well in California and would eventually serve as the raw material source for the production of wine corks to Californian wineries. Although the trees did flourish there, and in fact many are still growing there today, the cork bark on the California trees actually turned to hard “woody” bark not acceptable for production use. It is clear that even small climatic and soil differences will not allow commercially viable cork oaks to be grown outside the traditional geographic areas. The precise rainfall, wind conditions, and soil of the Mediterranean region are required to allow cork forests to flourish.

Forest Fires and the Cork Oak

Not only are cork oak trees important to the fauna and flora of the regions in which they grow. And not only are the trees a source of renewable raw material for the cork industry. The cork oak trees are also self-preserving. Many large forest fires ravaged the Mediterranean regions over the years with thousands of hectares blackened by the blazes. Pine trees and olive groves, eucalyptus trees and even vineyards have been burned and destroyed taking years to recover, if at all. Cork oak forests have not been immune to these massive fires either. However, the cork bark on these trees acts as a natural protective shield against the hot Mediterranean sun and the salty and sandy winds blowing off the sea and over the dry arid lands. The blazing fires that scorch the lands and the trees usually do not destroy the cork oaks. Indeed they too get scorched, but Mother Nature blessed the cork oak trees with fire resistent bark protecting the trees from total destruction. Although the brush and fields around and beneath the trees as well as the leaves of the trees are consumed by forest fires, thanks to the protective cork bark, cork oaks generally survive the fires and return to full growth within a short time. Nothing greater could highlight the insulating durability of cork and its protective qualities.

How Is Cork Harvested

Cork harvesting is the process of removing the bark off the cork tree. This is an extremely delicate operation made to look easy by the expertise of the cork harvesters. These experienced individuals use a machete to slice the bark into sections (the larger the section the better) and then they use a metal wedge to peel these sections from the trees. Although this is very strenuous work in itself, the harvesters need to take great care not to damage the very thin skin-like membrane which is found between the bark and the inner trunks of each tree. If this membrane were to be damaged it would weaken and perhaps kill the tree. It is this membrane that provides the nourishment to the cork trees. To register the harvest date and to ensure trees are not harvested again before the allowable nine years pass, after the bark is harvested from the trees the last number of the year in which the tree was last harvested is painted onto each tree (for example, if a tree was harvested in 2001, as shown in the picture, then the number 1 would be painted on the tree). This provides the control and assurance to both the forest owners and the environmental authorities that trees are not harvested before the ninth year following each harvest. This, among other cork forestry regulations, keep the cork trees in good health and producing good quality cork.

Every tree, therefore, is a source of renewed raw material. The cork is cut from the same trees time and time again. This goes on for generation after generation for some 200 years. A tree in its prime at 80 years old can yield 440 lbs (200 kg). This is sufficient raw material to produce approximately 25,000 natural wine corks. Although most cork oak trees are just slightly larger then olive trees there are certainly exceptions. The world record was set in 1889 by a cork oak in Portugal which yielded no less than 3,870 lbs (1755 kg) of cork in one harvest.

Protection of Cork Trees

Cork forests are carefully monitored and cultivated. Contrary to some beliefs and rumors, the health and sustainability of the cork oak is good and strong. In fact there are more cork trees today then there were some ten or fifteen years ago. It is true that some of the harvests passed through a few difficult years due to mismanagement of the forests in Portugal during several years in the 1970’s. It was a time of political upheaval in that country and after the 1974 revolution in Portugal many of the large cork forest holdings were nationalized by the new leftist government. In its flawed wisdom, the new government divided the forests into smaller allotments and appointed loyalist farmers sympathetic to their communal philosophiesto look after a particular section of land. These appointed and new landowners knew nothing of the requirements of good forest management and under their enforced watch the quality and yields of the cork became seriously strained. Fortunately the forests were eventually returned to the rightful owners but not before the damage was done. It took two full harvests (18 to 20 years) and a lot of repairs through proper forest management before the trees fully recovered their healthy yields. Today there are stringent cork forestry rules and regulations firmly in place and with Portugal a solid member of the European Union the political turmoil of the past will not be repeated.

DANIEL KUBINI Aka "Tutti"

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Globe of Corks

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Cork & Bottle Lamps

Miniatures

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