However, at that time, corks had not become mainstream. At that time, the most commonly used bottle stoppers in hip flask and jars were wax or gypsum, and olive oil was dripped on the surface of wine (reducing the contact between wine and oxygen). In the Middle Ages, corks were obviously completely abandoned. At that time, the oil paintings all described the use of twisted cloth or leather to plug a hip flask or wine bottle, and sometimes wax was added to ensure a tight seal.
It was not until the middle of17th century that the cork was really associated with the wine bottle. At that time, as another option, frosted glass bottle stoppers appeared from time to time to adapt to different bottlenecks. This bottle stopper has been used for a long time. Until 1825, these glass stoppers are still the choice of bottle stoppers. In the end, these glass stoppers were discarded, because there was almost no other way to take out these bottle caps except to smash the bottles. Before the cork was widely used as a practical bottle cap, there was a problem, that is, to find a tool that could easily drill into oak and take it out. A similar bottle opener was first mentioned in 168 1, which was described as "a steel worm used to pull out the bottle stopper". This hand tool was used to take bullets and soft fillers out of guns 50 years ago. Originally called a bottle opener, it was not officially called a bottle opener until 1720.
"Quercus variabilis" is the botanical name of a slow-growing evergreen oak tree, which only grows in some areas in the western Mediterranean. This kind of tree needs a lot of sunshine and a perfect combination of low rainfall and slightly high humidity. The quality and thickness of its bark vary with the specific environmental conditions in the place where it grows.
Because the bark has a soft protective layer, especially fire protection, oak trees can continue to grow. Many trees die because of the loss of bark, because bark can transport necessary energy-juice to the whole tree. This soft oak tree has two layers of bark. Inner bark is very important, which is the basis of new bark growth every year. When the old bark dies, the new bark shoulders the heavy responsibility of continuing to grow. The dead outer bark can be peeled off to avoid hurting trees, but be careful not to pierce the living inner bark.
Trees cannot be harvested for the first time until they are 25 years old. The oak harvested this time is irregular in size and density, which is not suitable for wine bottle stopper, and is usually used as floor or good insulation material. After 9 years, the tree can be harvested again, but the oak harvested this time is still not good enough to be used as cork. By the third harvest, the tree was 52 years old. At this time, the size, specifications and density of trees can make them suitable wine bottle stopper materials. An oak tree usually has 13- 18 useful harvests in its life.
Soft oak can be peeled off by hand with a sharp axe, and the bark will pile up and weather. Those trees whose bark has been stripped will be carefully marked and numbered so that future harvesters can know which trees can be harvested again.
Once transported to a factory in Portugal for processing, these oaks will be stacked again and air-dried for up to 3 months. Proper humidity is very important for the elasticity and compressibility of oak. After air drying, the cork will be soaked in boiling water for 90 minutes, one is disinfection, and the other is flattening its curved shape. Then, the cork should be left for 3 to 4 weeks to achieve the ideal humidity. Then these materials will be arranged neatly one by one, and then the cork will be punched on them according to the size and required shape of the bottle. In this stamping process, the punching machine needs to concentrate on producing the highest quality products. After that, the head and body of the cork are polished to make all the corks have the same length and diameter. It should be noted that the thickness of the bark determines the diameter of the cork, not the length of the bark, so the annual rings of the tree are vertically implanted with the cork. Then the cork is cleaned and dried, and most of it is bleached with chlorine or hydrogen peroxide, which can not only disinfect, but also remove residual impurities. Some are not bleached, depending on the needs of the winery. Corks will be graded according to quality and marked with the name of the winery. Finally, the surface of the cork is sprayed or coated with silica gel, paraffin or resin, which is convenient to plug into the bottle mouth and can improve the sealing performance of the glass bottle. Then, it can be delivered in a plastic bag.
The emergence of problems
"Cork smell"-the smell that wine gives off in a short time after being polluted by a chemical called 2,4,6 trichloroanisole (TCA). This substance is produced when cork comes into contact with moisture, chlorine and mold. From harvesting cork to bottling wine, cork may come into contact with these three substances, leading to the formation of TCA. As long as the concentration reaches four parts per trillion, people's noses can smell the cork. Wine with a slight cork smell may just smell like oak, but heavy wine smells like moldy wet cardboard or old newspapers. In this case, the rich fragrance, fruit fragrance and oak fragrance will be taken away by this moldy smell. Cork-flavored wine is by no means harmful to health, it just smells and tastes bad, and the most serious problem is that you spent a lot of money on a bottle of inferior wine, and you can only know something about it if you open it. It's just that if he meets a reputable merchant, he will replace those polluted wines.
substitute
About 6% of the wines listed in Wine Appreciation magazine have tasted cork. Why is this defective cork still used in this industry?
As a bottle stopper, the cork with fine tradition will gradually disappear. Although many people think that the use of cork is a noble historical relic, it makes it a difficult and learned action to open a bottle. Have readers seen those abstruse restaurant opening ceremonies? Screw-top wine gives people the feeling that it is a "bargain". So where is the answer? Now there are synthetic plugs made of polyethylene, such as Cellukork brand. These corks look and smell like real corks, and they need a bottle opener to take them out. But it has two disadvantages: first, it fits tightly with the bottle and is difficult to take out. This problem will definitely be solved through research. The other is the potential worry. Are these synthetic materials really unresponsive and inert after a long time? Will it affect the taste of wine? Obviously, for those who keep wine in the cellar for a long time, this is really something to worry about. Wineries have been experimenting with storing wine with these plastic stoppers for a long time to see what will happen, but the final result will have to wait for several years.
Let's go back to the screw cap. Not only airtight, but also humanized-even if you forget the bottle opener, you don't have to work hard. It also makes wine feel at home, without the deep impression that people always associate it with "nobility". Therefore, the screw cap makes wine more acceptable in image and practice. The problem is, it's the same old topic: Chen Fang. Can screw bottle caps preserve wine well for a long time? However, no one has conducted conclusive experiments. The main problem is that many quality-oriented winemakers are very concerned about the quality wine market. They don't want to use screw caps instead of corks because they don't want their products to be considered inferior. Similarly, this is also the impression formed by the industry itself.
Final answer
It is precisely because of the world's concern about the decline of cork quality and its great influence on cork industry that a group of American cork suppliers set up the "Cork Quality Committee" on 1992. The Committee's duty is to improve the quality of bottle stoppers from the root, establish educational programs to help wineries, and formulate industry standards for bottle stopper quality. The research on synthetic bottle stopper is still going on. Many wineries are now experimenting with plastic corks. If there is no problem, more wineries may follow suit.
No matter what bottle stopper is used for a bottle of wine, the wine itself is the ultimate experience. Whether we unplug the cork, unscrew the screw cap, or open the amazing wine in other ways, the most important thing is the enjoyment that wine brings us in our daily life.
[Edit this paragraph] From bark to cork
1. It usually takes 6 months to 1 year to produce a cork from the beginning of bark peeling. In Portugal, the largest cork producer in the world, the harvest season begins in May and ends in June. When harvesting, workers carefully peel off the cork layer of Quercus variabilis (deciduous oak with soft and elastic "cork layer" in its bark), not too deep, otherwise the tree will die because it can't resist parasites. After each harvest, it takes 9 years to peel the cork layer from the same oak tree. The life span of a healthy Quercus variabilis is 200 years, and it can only be peeled 16 times at most.
2. The stripped cork layer is stored outdoors. Good sunshine in summer can dry the moisture in the cork layer; The continuous rain in autumn washed the tannins in the cork layer. In jargon, this period is called the "stable period" of cork, which lasts for half a year, and there is a danger of mildew if it is longer.
3. Dry cork can be cut into cork. Cutting is also an art, and experienced workers can judge the quality of a plate at a glance. The cut crumbs can't be wasted, they are collected and are good materials for processing polymer corks.
4. Cork products should be disinfected and selected, and products with thin edges or cracks on the surface should be picked out. High quality cork, the surface must be smooth, and the pores are small and few.
[Edit this paragraph] cork national standard
In recent years, China's wine industry has developed rapidly, but few people have studied the cork, which is called "the guardian of wine life". As a result, there has been no national or industrial standard for cork in China, and the cork industry is in serious disorder competition. In order to change this situation, the National Quality Supervision and Inspection Center for Wine, Liquor and Dew Liquor has worked out the national standard of "Corks for Wine and Other Food Packaging" for more than two years. The standard has been strictly examined by experts in the scope of application, the use of technical terms and the uniformity of format. Detailed, scientific and standardized, with strong operability. The Corks for the Packaging of Alcohol and Other Foods stipulates the terms and definitions, product classification, requirements, test methods, inspection rules, marks, packaging, transportation and storage of corks for the packaging of alcohol and other foods. The cork used for wine and other food packaging is suitable for the cork used in wine, beverage and other food packaging containers.