Early in the morning antiquity knew that Assyrian. Egyptian and Greeks the cork. In part, cork stoppers were also used as a closure for vessels like amphorae used. Mostly, however, pots made of terracotta (clay) were in use, which were attached with string and then sealed with paint, clay or pitch. The Roman author Cato the Elder (234-149 BC) writes that the wine jugs after the fermentation would have to be closed with cork and pitch. The Romans already knew this type of closure, but it was forgotten with the fall of the Roman Empire. This was probably because the Iberian Peninsula, the main source of cork bark, was conquered by the Moors in the 8th century and ruled for a long time. Until the late Middle Ages vessels were sealed with oil-immersed and hemp-wrapped wooden plugs, pitch or wax.
With the development of glass bottles Glass caps were first used, but at the beginning of the 17th century the cork was rediscovered. Also the monk and alleged inventor of the champagne cathedral Pérignon (1638-1715) experimented with it. The corks initially had a conical shape due to bottle neck sizes and were only half sunk for easier removal. Only by developing usable corkscrews they got a cylindrical shape and were now fully driven into the bottleneck. As the dominant type of closure for bottles The cork then became established in the middle of the 17th century, which subsequently led to a rapid boom in the cork industry.
Today, the natural cork is mainly made from the thick outer bark of the most suitable cork oak "Quercus suber". More than half of world production comes from Portugal, other important countries are Spain, Algeria, Italy and Morocco. The trees are up to ten meters high and can be used for about 200 years. They can only be peeled for industrial use for the first time at the age of 25; For corks, the bark is suitable only from 45 years. This is repeated at intervals of 9 to 12 years; A tree can be debarked about 15 times. The bark is aged for at least one year, then cooked in water, pressed, cut into slices and sorted by quality.
From this strips are cut, from which one punches out the cylindrical plugs. They are produced in a length of 38 to 60 mm; longer corks usually mean a higher wine quality. The blanks are smoothed on the front surfaces and ground round. Thereafter, bleaching and impregnation are performed with a waxy substance to lubricate the cork. Last is the cork brand, today this is mostly an imprint. When packing the corks is often used for conservation sulfur added.
A natural cork is a nearly ideal and also undisputed aesthetics ago an optimal closure for wine and sparkling wine bottles. It is light, clean, relatively insensitive to different temperatures, rarely infested with rot, healthy in nature, impermeable to air, extremely elastic, with a long life of typically 10 to 20 years, in exceptional cases 50 years or more. The cork cells are impermeable to gas and water by the incorporation of suberin (waxy pulp). In each bark (bark) gives however places with so-called Lentizellen (for gas and water exchange). For the quality of a cork as few as possible are advantageous. A normal wine bottle cork has a diameter of 24 mm and is compressed to the bottleneck diameter of 18 mm. But even after years of storing bottles after 24 hours, it returns to its original size after being pulled.
The humidity must be high enough so that the cork does not give off moisture to the environment (ideally 75% at 10 ° C). But like all organic substances, a cork loses its suppleness and thus its ability to block as it grows older. Therefore, it is advisable to drink a bottle with a defective cork in time or cork again. A few wineries offer their customers the special service of one Neuverkorkung for very old bottles of their best products. In extreme temperature fluctuations, the cork can be leaking; which is prevented by uniform temperature. On the cork can be Weinstein crystals deposit, which can lead to a certain impairment in terms of tightness.
An often asked and discussed question is whether the wine "breathes" during storage through the cork and whether and to what extent oxygen for the development of the wine during the bottle aging or for the durability is required. Perhaps the small amount in the bottleneck is enough, but today this room is mostly with inert gas filled or creates a vacuum when closing. Natural corks are compared to other alternative closures such as conventional Plastic corks or screw caps up to a factor of three or four more permeable. Recent research on AWRI (Australian Wine Research Institute) have in any case revealed that a controlled intake in the smallest amounts, ie in a more uniform OTR (Oxygen Transfer Rate) very positive flavorings and colour especially of red wines. The required amount, however, depends, among other things, on the vine, So that would be the case for the natural cork, but in the meantime there are alternatives closures with which you can individually control the oxygen supply.
Press corks (also composite corks or agglomerate corks of agglomerate = agglomerate) are not cut out in one piece from the cork oak, but it is bound by resin or glue cork granules. These are much cheaper than natural corks. As a rule, a piece of two to three mm length of normal natural cork is applied to both sides, so that the wine does not come into direct contact with the glue. Such types are referred to as "1 + 1 corks" or "2-slice corks." Press corks are mostly used for young wines. They are considered less storable, because there is also a risk of crumbling.
For cost reasons, a sparkling wine cork is often divided into two parts. While the upper part (head) consists of press corks, two discs of natural cork are glued to the bottom, which are in direct contact with the sparkling wine stand. Because of the opposite one Still wine much higher pressure within a sparkling wine bottle, there are some special features to ensure the fixation of the cork. Although sparkling corks are also cylindrical, they are much thicker. The diameter of an uncorked sparkling wine cork is usually 30.5 mm and its length 48 mm. When inserted into the neck of the bottle, the cork is compressed to 19 mm, which results in a much stronger seal and the typical mushroom shape at the top of the bottle neck protruding part. The cork is additionally with a Agraffe (Wire mesh) fixed, with a small metal capsule (plaque) protects the cork from being cut through the wire.
At a champagne must on the cork mandatory the text "Champagne", at one Millésime (Vintage champagne) in addition the year appear. After removing the cork from the bottle, it also gives some indication of its storage life (usually a sparkling wine should be enjoyed as soon as possible). If it goes with the lower part (foot) in the width, it is called "Juponne" (jupon = petticoat) and the bottle was probably corked less than a year before. A narrow foot is a "cheville", which means corking a long time ago.
Today cork comes in increasingly poorer quality (large pore) on the market because of the enormous demand cork. Either they are leaking or due to the porosity oxidative Processes and in extreme cases, the leakage of wine. By unclean cork production can also the corked arise. The therefore ideal closures would be alternatives such as screw cap, Not a few are complaining about it, miss the "plop" and complain about a loss of culture, but probably this development is over ecological and economic reasons unstoppable. In addition, the often used pro-argument for the "pop" as a sensual pleasure is not valid, because a bottle should be opened noiselessly. Currently, nearly 60% of wine bottles worldwide are closed by natural corks. See also below closures,