It’s no secret that wine in a bottle with a cork does change with time as oxygen seeps slowly in through the pores. A bad cork, which can be found in even the most expensive batches, will ruin the wine it’s in contact with. However, there are wines that can and do evolve in the bottle, and the vast majority are ready to be drunk as soon as they’re bottled. Subsequent interaction with the atmosphere through the cork can only hasten their decline.
Corks of the highest quality normally remain good for decades. However, with the increased demand for corks, more lower quality ones are being used, resulting in many starting to crumble at 10 to 15 years. Several years ago, the industry became aware of what seemed to be a growing quality control problem with corks. Winemakers began moving to alternatives in the past decade because of problems with cork that were ruining wines. The cork industry did react as winemakers fled to other options, cleaning up its production and screening the process to cut down on taint, such as using better wood and quicker drying methods.
Today, the wine industry is rapidly embracing alternatives to natural cork. The most promising of these are the synthetic cork, screw-caps and, most recently, glass stoppers.
Synthetic corks, derived from plastic, appeared to be a viable alternative. A synthetic cork is designed to look and function like natural cork. They are made from plastic compounds that are designed to look and “pop” like natural cork, but without the risk of TCA contamination. There are three main production techniques for synthetic wine closures: injection moulding, extrusion moulding and the Vinova-type production, which combines the advantages of both injection moulding and extrusion moulding. A 2007 study at
A wine that has spent too long in a bottle with a plastic cork will prematurely age, causing the wine to lose fruity aromas. Plastic corks can also impart a slight chemical flavour to the wine. Unlike natural corks, many synthetic corks are made from material that is not biodegradable. The other problem is the question of whether the synthetic material is truly non-reactive and inert over long periods. Will it impart no flavours of its own to the wine? Over time, these corks can absorb flavours from the wine known as scalping. Naturally, wineries using these plastic corks are deliberately ageing wines to see what happens, but it is too soon by several years to know the outcome. One other concern about synthetic closures is the ruthless efficiency with which they strip the Teflon coating from more expensive models of corkscrews.
Nonetheless, more and more low- and mid-range producers are switching to synthetic corks because they are the cheapest to manufacture, are 100% TCA-free and marketing departments love to print anything they like on them. Of course, it should be pointed out that some makes of plastic cork are more efficient than others, and product development is occurring all the time, so we may yet see serious plastic alternatives to corks.
Screw-caps became a popular option and are now seen topping many fine wines. The modern metal bottle cap was developed by the prolific
In the 1960s, the Coca-Cola Company offered lift-top crown caps. The push-on, twist-off cap was first developed for baby food. Screw-caps for carbonated beverages appeared in the 1960s and 1970s and are the standard today. The traditional crowned bottle cap has been used in the sparkling wine industry as a closure during the bottle fermentation process. Normally, the cap is replaced with a cork before shipping, though recently, some producers are releasing wines using the crown cap as their closure. The crown caps provide a tight seal without risking cork-taint. Although easier to open, crown caps eliminate part of the ceremony and mystique of opening a sparkling wine.
Screw-caps are made up of two parts: a metal outer capsule and a disc typically made from a layer of tin sandwiched between PVDC and white polyethylene. A screw-cap provides the best seal for bottled wines, and eliminates the “corked” and oxidation problem. It provides an excellent air-tight seal, although there is a question as to whether or not it will protect the wine over a very long period of time. A university study in
But with the widespread use of screw-caps in wine during the last few years, some technical issues have emerged, surrounding post bottling sulphur chemistry, known more commonly as “reduction”. Closures study by the Australian AWRI showed that while the screw-capped wine kept fruit freshness and retained free sulphur dioxide the best of all closures, it suffered from a sensory defect described by the experts as a “rubber-like character”. This was attributed to the lack of oxygen. The tests by AWRI indicated that an anaerobic closure is not appropriate for all types of wine.
As mentioned above, the screw-cap is simply a means for holding a liner in position to the rim of the bottle. It is the properties of this liner that determine the oxygen transmission levels of the closure. Additional findings from research in the field of screw-cap closures showed that the post-bottling development of the wine is influenced by a number of factors, including the state of the wine at bottling, the free sulphur dioxide level, the oxygen pick-up during bottling, headspace extent and the oxygen transmission through the closure.
So far, the evidence obtained suggests that the issue of bad odours in screw-capped wines due to lack of oxygen is problematic, and winemakers should pay more attention to the potential loss of quality over time. Currently, the extent of screw-cap reduction is unclear. As with synthetic closures, there isn’t yet the necessary weight of evidence concerning long-term ageing necessary for important producers to switch from cork to screw-cap. Aside from the quality issue, the image of a screw cap is firmly lodged in many minds as an indication of a cheap wine. Many wine producers, sensitive to the fine wine market, hesitate to switch to a screw-cap because they do not want their wine to be perceived as of inferior quality.
Using a glass stopper with an inert o-ring creates a hermetic seal that prevents oxidation and TCA contamination. A disadvantage with this closure is the relatively high cost of each plug, as well as the cost of manual bottling due to the lack of compatible bottling equipment outside of
A screw-cap costs about the same as a low-priced cork. A plastic cork is much cheaper. But the debate about the effectiveness of these methods of closure rages on. The main concern is that there is not sufficient proof as yet that wines bottled using synthetic closures age in the same way as those bottled using natural cork, a proven although admittedly imperfect material.
At the moment no one can claim that there is a perfect closure. All of them have their advantages and their disadvantages. Wine bottled under cork tastes mellow, sweeter (similar to sweet oak), richer, more open and more evolved. It also tastes lower in acid, which translates to a perception of sweetness.
Wines bottled under screw-caps taste fresher, higher in acid, younger, tighter, and more mineral. The lack of oxygen means that the wine tends to keep its fruity character longer and does not oxidise (turn to vinegar) as quickly. However, screw-cap wines tend to be more reductive (the opposite of oxidisation). Too much reductive character in the wine is not the best, and flavours such as burnt matches, onion, garlic, cabbage, nuttiness, cat’s pee and sweaty aromas can occur. Lower levels of reductive characters are thought by some to produce the mineral character in many fine wines as well as green pepper and blackcurrant notes in some. So as with oxidisation in wine, a small controlled amount can be good, but too much is usually a problem. While it’s clear that corks don’t allow very much air transfer (if they did, the wine would rapidly disintegrate), they may allow just a tiny amount.
During the last 300 years, natural cork has had a monopoly, and it is apparent that there will never be another monopoly. Synthetic corks, screw-caps, even glass stoppers are some of the alternatives undergoing intensive scientific research and in the last 10 years, we have probably seen more innovation in closures for wine bottles than we have in the past 100 years. The emerging competition has even caused the cork industry to innovate, which is great. It is an exciting time at the moment with closures for wine. It is going to continue to be so, but ultimately, it’s the marketplace that decides.
If the main goal of the winemaker is to produce quality wines that require bottle ageing in order to improve, then the option of natural cork seems to be the most appropriate. Advantages for the storage of wine with natural cork have already been outlined, but a very important factor is that cork has proven itself to be a relatively good and reliable option for more than a century. What also looks obvious is that until more experience in ageing premium wines is gathered and more research is conducted, these wines will continue to use natural cork. At present, top producers of premium and cult wines are not keen on taking any risk and are very reluctant to use other closures than cork. Also, the consumer is not used to seeing a prestigious wine being associated with plastic or non-natural closures.
Currently lacking are independent, statistically robust data showing how alternative closures perform over extended periods. Until the data show that the performance of the various alternative closures closely tracks that of natural cork over extended periods, most wine producers will probably stick with the latter for sealing their fine wines intending to cellar for more than a couple of years.
In general, people like corks. They’re natural, they look and feel right, and the ritual of getting the corkscrew out is part and parcel of the wine drinking experience. Furthermore, while most experts now agree that the screw-cap is the closure of choice for fresh white wines and easy-drinking reds, there’s some debate about whether they are suitable for red wines destined for long ageing. Not enough research has been carried out to date to sort out the problems and find the solutions, if the problems can be solved. The reason for this doubt is that people like the way that fine wines evolve over time when they are closed with a fault-free cork. At the end of the day, it is the winemaker’s decision to use the right closure, but it is for the marketer to decide what’s appropriate for where that product will be sold. It is not just a winemaking issue: we have to deliver what the market requires.
Wine News and Information
A British survey has found that affluent professionals who earn more than $100,000 a year, drink more than twice as much wine as the average person, in many cases exceeding safe drinking limits. These pleasure-seekers also visit restaurants more often than most, dining on rich, fatty food. As a result of their lifestyle, they face serious health risks, even though they may not appear unhealthy.
Most of these work-hard, play-hard professionals assume that they are healthy by drinking red wine, which, in small amounts, has purported heart-protective benefits. But when it is served in huge goblets, they drink way too much. A large glass of red wine can contain as much as three units – more than the recommended daily maximum for women. And experts warn that eating lots of fat and drinking too much helps fat gather around the organs, raises cholesterol and dilates the heart.
The French drink less than previously thought, according to new figures that question the way the government has been measuring drinking statistics. The APV (Association Presse du Vin) has claimed that the official statistics have aided the anti-drinking lobby which is becoming increasingly powerful in
The International Organisation of Vine and Wine (OIV) announced that about 266.7 million hectolitres of wine was produced in 2007, 6.9% less than in the previous year, while consumption was roughly unchanged at 240.6 million hectolitres. About 7.899 million hectares of land was given over to wine production in 2007, down from 7.908 million a year before. The sharpest production decline has been in
Ribera del Duero has created a wine with “charisma” and “unique sensibility” to honour the gay community. This is “a small step in making homosexuality normal and acceptable”, according to Mundo Gay spokesman Fernando Martín. “With gay marriage having been introduced in
Monolithos Monthly News
Weed control is the single most important cultural practice in any vineyard, particularly during springtime. The soil is worked again and unwanted vegetation is removed. Without weed control, other cultural practices such as cultivation, nitrogen fertilization and vine pruning severity will be incapable of promoting vine size development. When these cultural practices are used in combination with weed control, however, they can have a positive, additive influence on vine growth. We at Monolithos subscribe to the philosophy that wine quality is dictated mainly by the grapevines, or in other words, the better the grapes, the better the wine. If you have a proper growing site that has good drainage, access to full sunlight and nutrient-poor soil, you can micromanage their development and pick them at the moment of perfection.
During the last few weeks, the Ayios Stephanos 2007 production, both white and red wines, were cold stabilised and bottled. All 2007 white wines and the new “Monolithos Red” are now ready for tasting or purchasing.
If at any time you are passing near the
We thank you for your continued support, take care and remember the words of the British author Rebecca West (1892-1983):
