cork
The cork is an elastic , largely water and gas-tight bottle stopper made of cork , primarily for wine , champagne and fruit brandy bottles . In Austria the cork is also referred to as a stubble (from to close ), in Switzerland as a cone.
history
As early as ancient Greece , Assyria and ancient Egypt , cork stoppers were pressed into the openings of amphorae to close wine vessels. Until the late 17th century, however, wooden plugs and clay plugs dipped in oil and wrapped in hemp were mostly used.
The Benedictine Pierre Pérignon discovered around 1680 that these stoppers had jumped out of the sparkling wine bottles after a long transport . He replaced them with cork stoppers. Other champagne houses adopted the locking system as early as the first half of the 18th century . Cork did not gain real importance as a bottle stopper until the end of the 18th century: trade and economic relations expanded, so it made sense to close bottles tightly.
Around 1855, corks were only produced in Delmenhorst in the German Empire . In Eisenacher Oberland, where production had also started around this time, there were 126 main and 197 part-time businesses in 1874. In 1919, 14% of the empire's industrial operations for cork production were in the administrative district of Dermbach , which corresponded to second place. Since the 1800s, the situation of producers in the Rhön has been made more difficult by the introduction of the cork planer, the lowering of import duties on cork products from Spain and Portugal and the introduction of patent locks. Nevertheless, corks were produced "on a large scale" in Dermbach and Geisa .
However, the great boom in cork production began in 1890. Within the next 40 years, the number of people involved in cork production increased fivefold.
Manufacture and use
Corks are made from the robust, largely fire-resistant bark of the cork oak (Quercus suber) which is widespread in the Mediterranean region . The bark can be harvested after the third peeling at the earliest. H. around the 40th year of the tree's life. Subsequent peeling can take place every nine to ten years. On average, around 150 kg of cork are then harvested per hectare of trees. Portugal is the world's largest producer of corks.
If one uses a stopper cut from the bark with hollow knives, one speaks of "natural cork". These corks are considered to be the highest quality and most durable variant. In order to save costs, corks are also made from cork granulate. Here, small pieces of cork are pressed together with glue or resin under high pressure to form a cork. A cork made in this way is called a “press cork”. Press corks are mainly used for cheap wines and are considered less storable. The risk of crumbling is greater with stuck corks than with natural corks. At the end, press corks are sometimes provided with a waxed cork disc to prevent direct contact with the compound and to ensure taste neutrality. Press corks designed in this way are called "composite corks". If discs are glued to the top and bottom, one speaks of "1 + 1 cork" or "2-disc cork"
The insertion of a cork ( corking ) is usually machined in such a manner that the cork first by a conical so far compressed press that its diameter is slightly smaller than the inner diameter of the bottle neck. It is then pushed into the neck of the bottle at high speed. As the pressure is no longer available, the cork expands and presses itself against the inner wall of the bottle neck (with champagne corks, the additional attachment is made by the clasp ).
An average wine cork has a length of approx. 38 mm to 60 mm. The raw material and the length of the cork are decisive for the quality of the cork. Good corks are smooth, firm and long, and they have as few pores as possible. Since corks are a natural product, it is quite possible that cork lengths vary within a year.
The diameter of a standard uncorked cork is 24 mm. It is compressed to 19 mm in the bottle neck. The diameter of an uncorked champagne cork is usually 30.5 mm and its length 48 mm. However, the diameter and size vary according to the bottle size.
To increase the tightness, the cork is usually covered with a thin silicone - rubber layer (previously: paraffin ).
The cork is usually removed by the consumer using a corkscrew . The cork can break, especially if it is old. Corks that are to be reused are often provided with a plastic disc that you can touch. These corks are called "handle corks". They are significantly shorter than corks that are supposed to be removed with corkscrews.
It is common to label corks. This label is called cork fire . The cork brand serves, among other things, to make counterfeiting more difficult.
properties
After natural cork had been the preferred type of closure for wines for decades, the opinion of producers, consumers and experts about which would be the preferred type of bottle closure is gradually changing. According to the latest findings, the natural cork seems to be subject to this in the long term.
In addition to the high cost of natural cork, this is primarily due to the disadvantages of this type of closure:
Corks made from natural cork can occasionally create a “ cork taste ” in wine . The substance 2,4,6-trichloroanisole (TCA) is responsible for this. Approx. 2–10% wines spoiled by TCA are assumed, and the tendency is slightly lower due to improved bottling conditions. Robert Parker, Jr. speaks of 7-10% of the wines he tasted. A wine with a cork taste is described as “ cork taster ”, or one simply says “it corks”. In Austria the phrase "he has a stubble" is often used, in Switzerland they say "the wine has cones". Wine spoiled by trichloro anisole smells musty and has an unpleasant penetrating aftertaste, which can range from a light note, which some people do not even notice, to completely inedible. According to a comprehensive study by the Department of Cellar Management at the Geisenheim Research Institute in Hesse , the wrong tone in the cork can occur due to contaminated natural corks due to incorrect storage. According to this, wooden beams and wooden pallets are said to have been treated intensively with a wood preservative that contains the toxic chemical pentachlorophenol (PCP). In a humid environment, molds in wood convert the chemical into trichloro anisole (TCA), which escapes into the room air and contaminates it to the extent that TCA is deposited in organic material such as cork. Press corks, like natural corks, are at risk. However, the cork is not the only possible source for the cork connoisseur.
In addition, over the years, cork also loses its elasticity and shrinks. The risk of oxidation of the wine increases. The filling level of bottles closed with natural cork therefore decreases after a few years of storage depending on the storage conditions.
The advantages of the cork include the fact that it is a renewable resource and its neutral taste. Natural corks are valued above all for their tried and tested long shelf life.
recycling
Natural corks have been increasingly collected as a reusable raw material for recycling since the 1990s . The corks collected and cleaned of metal parts are ground into granules and used as a loose filler or as pressed panels as a building material for thermal insulation . Most bottle corks are collected and reused in Switzerland.
Alternative materials
For several decades, alternative wine closures have been tried out worldwide because of the relatively high cost of natural corks and because of the above-mentioned disadvantages, which often lead to inedible wines.
Glass closures
Vinolok glass closures have been in series production since the end of 2004. They have a seal made of EVAC (ethylene-vinyl acetate copolymer), which z. B. was offered under the brand name Elvax by DuPont (since 2019 by Dow ). The closure is about as expensive as a natural cork and is also intended for high-quality wines.
Bottle caps
Crown corks , which are much cheaper than corks, are also used, but do not catch on as much as the screw cap. Foam or foils determine the sealing of the liquid volume and the gas exchange with the atmosphere. The metal cover protects against mechanical damage.
Plastic stopper
Plastic plugs are u. a. manufactured as a homogeneous foam body with a dense skin or as a two-layer foam body with an additional pore-free shell on the cylinder wall. The foam is mixed, melted and extruded from the raw material in one operation, so that a long foam strand with an outer skin is created, which is then cooled and cut. With coextrusion , a flexible outer layer is applied before cutting, which has better physical properties than the skin of the foam body. The oxygen uptake of plastic stoppers and natural corks are both in the range of 4–40 mg / l O 2 per year: for cork due to natural differences, for plastic corks depending on the manufacturing process.
In the meantime, closures made of polyethylene - also known as biopolymer - are made, which are obtained from sugar cane and have a great visual resemblance to natural corks. They achieved very good results in tests carried out by the Geisenheim research institute.
Screw cap
While the traditionalists have long resisted the alternatives and pleaded for natural corks, it can be said that alternative closures are gradually gaining acceptance. In New Zealand in 2011 90% of all wines were sealed with screw caps , in Australia it was already over 60% of all wines in 2010. The screw cap is also gaining a foothold in Germany. B. 81% (as of 2010) who are provided with this closure. Since the early 1970s , a screw cap that is also suitable for storable wines has been tried out. This special screw cap for wine bottles is also called the Deonym Stelvin. Tests of wines that come from the same barrels and were sealed with both types of closure have shown that white wines in particular can benefit from screw caps. It is believed that the airtight seal leads to better freshness in these wines, which is generally seen as an advantage. The Australian tests with red wine, which have been ongoing for decades, show an aging behavior that is almost identical to that of high-quality cork. That is why more and more Australian producers have been using screw caps for their red wines since the beginning of the 21st century. Only in the case of wines that are expected to have been stored for decades are waiting to be converted. Consumer acceptance is also growing: in Australia, 55% of all consumers already prefer screw caps to corks, in Great Britain it is 40% and in the USA 21%.
Individual evidence
- ↑ wein-plus.eu
- ↑ Amphorae - the lock , on antike-tischkultur.de, accessed on April 9, 2016
- ^ The wine lexicon: Entry cork , on hawesko.de, accessed on April 9, 2016
- ↑ Silesian Society for Patriotic Culture: Annual report of the Silesian Society for Patriotic Culture, Volume 96 , Aderholz, Breslau 1919, p. 42, full text in the Google Book Search USA
- ↑ From the cork oak to the cork (PDF) p. 3., on natuerlichkork.de, accessed on April 9, 2016
- ↑ Kork Info , on iberia-kork.de, accessed on April 9, 2016
- ↑ Press corks - an alternative to natural corks , on iberia-kork.de, accessed on April 9, 2016
- ↑ a b Stoppers: cork or screwcap? , at jancisrobinson.com, accessed April 9, 2016
- ↑ iberia-kork.de
- ↑ iberia-kork.de
- ↑ Closures for wine bottles , on wein-plus.eu, accessed on April 9, 2016
- ↑ iberia-kork.de
- ↑ wein-plus.eu
- ↑ Wine with cork versus screw cap , on nikos-weinwelten.de
- ↑ Screwed not Corked , on wineeconomist.com
- ↑ Is There a Cork Shortage? ( Memento of the original from March 4, 2016 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , on lydony.com
- ↑ Why screw caps ( Memento of the original from December 22, 2015 in the Internet Archive ) Info: The archive link has been inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , on coyotesrunwinery.com
- ↑ Bringing closure? A screwcap-cork showdown , on drvino.com
- ↑ a b Why the snobbery over corks? , on bbc.com
- ↑ Chemical contaminated sites ruin noble wines , on spiegel.de
- ↑ The wine cork - 8 misconceptions and does the classic wine bottle stopper really die out? , on der-weinmakler.de
- ↑ Corks vs Screw Caps , winefolly.com
- ↑ The History and Revival of Screwcaps , on wineoftheweek.com
- ↑ a b c Report on comparative analysis of wines sealed with Vinolok and alternate closures (PDF), on vinolok.cz.
- ↑ Production of the foam body (PDF).
- ↑ Volker Schneider: Screw cap and wine aging. In: Die Winzer-Zeitschrift , NO. 03, 2008 (PDF).
- ↑ Introducing the world's first zero carbon footprint wine closure ( Memento of the original from November 5, 2015 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. , on nomacorc.com
- ↑ theaustralian.com.au
- ↑ nikos-weinwelten.de
- ↑ drvino.com
- ↑ theaustralian.com.au
- ↑ coyotesrunwinery.com ( Memento of the original from December 22, 2015 in the Internet Archive ) Info: The archive link was automatically inserted and not yet checked. Please check the original and archive link according to the instructions and then remove this notice.
- ↑ chrisshanahan.com
- ↑ drinksint.com
Web links
- The wine cork - 8 misconceptions and does the classic wine bottle stopper really die out? , on der-weinmakler.de, accessed on March 10, 2015