October 2010 - Posts
Wine is one of the few commodities that can improve with age but it can also rapidly deteriorate if kept in inadequate conditions. The three factors that have the most direct impact on a wine’s condition are light, humidity and temperature. A fourth consideration can be security, since wine can be considered a luxury good with value on the after-market. Here’s a lowdown on how to store wine to retain that perfect blend and taste.
Storage is an important consideration for any wine that is being kept for long-term aging. While most wine produced today is meant for near-term consumption (with much being consumed within 24 hours of purchase), there are certain situations in which it may be set aside for long-term storage. Historically, the long-term storage of wine was handled by wine merchants, but since the mid-20th century the task of handling and storing wine has increasingly fallen to consumers. Industries relating to specialty wine storage facilities and the construction of home-based wine cellars have emerged to cater to the storage needs of consumers.
Conditions affecting wine
In wine storage conditions, there are three factors that have the most pronounced affect on the wine: light, humidity and temperature. Direct light, whether it be sunlight or incandescent, can adversely react with phenolic compounds in the wine and create potential wine faults. Delicate, lightbodied white wines run the greatest risk from light exposure and are often packaged in darkly-tinted wine bottles that offer some protection from the light. Wines packaged in clear, light green and blue coloured bottles are the most vulnerable to light and may need extra precautions for storage. For example, the Champagne house of Louis Roederer uses cellophane wrap to protect its premium cuvee Cristal from light, the wine being packaged in a clear bottle. In the cellar, wines are stored in cardboard cartons or wooden crates to protect the wines from direct light.
Some degree of humidity is required in order to keep wines with cork enclosures from drying out. Even when wine bottles are stored on their sides, one side of the cork is still exposed to air. If the cork begins to dry out, it can allow oxygen to enter the bottle, filling the ullage space and possibly causing the wine to spoil or oxidise. Excessive humidity can also pose the risk of damaging wine labels, which may hinder identification or hurt potential resale value. Wine experts such as Jancis Robinson note that 75 per cent humidity is often cited as ideal, but there is very little significant research to definitively establish an optimal range. Concern about humidity is one of the primary reasons why wine experts such as Tom Stevenson recommends that wine should not be kept in a refrigerator since the refrigeration process often includes dehumidifying, which can quickly dry out corks.
Some wine experts debate the importance of humidity for proper wine storage. Famous wine writer Matt Kramer cites a French study which claimed that the relative humidity within a bottle is maintained at 100 per cent regardless of the closure used or the orientation of the bottle. However, Alexis Lichine contends that low humidity can still be detrimental to premium wine quality due to the risk of the cork drying out. As a way of maintaining optimal humidity, Lichine recommends spreading half an inch of gravel on the floor of a wine cellar and periodically sprinkling it with some water.
Wine is very susceptible to changes in temperature, with temperature control being an important consideration in wine storage. If the wine is exposed to too high a temperature (in excess of 77 °F (25 °C)) for long periods of time, it may become spoilt or ‘cooked’ and develop off flavours that taste raisiny or stewed. The exact length of time that a wine is at risk of exposure to high temperatures will vary depending on the wine, with some wines (such as Madeira which is exposed to high temperatures during its winemaking) being able to sustain exposure to high temperatures more easily than other, more delicate wines (such as Riesling). If the wine is exposed to temperatures that are too cold, the wine can freeze and expand, causing the cork to be pushed out; this will allow more oxygen to be exposed to the wine. Dramatic temperature swings (such as repeated transferring a wine from a warm room to a cool refrigerator) can also cause adverse chemical reactions in the wine that may lead to a variety of wine faults. Most experts, such as Jancis Robinson, recommend that wine be kept at constant temperatures between 50 and 59 °F (10 and 15 °C). Tom Stevenson speculates that 52 °F (11 °C) may be the most ideal temperature for storage and aging.
The storage condition of the bottled wine will influence a wine’s aging. Vibrations and heat fluctuations can hasten a wine’s deterioration and cause adverse effect to it. In general, a wine has a greater potential to develop complexity and a more aromatic bouquet if it is allowed to age slowly in a relatively cool environment. The lower the temperature, the more slowly a wine develops. On average, the rate of chemical reactions in wine doubles with each 18 °F (8 °C) increase in temperature. Wine expert Karen MacNeil, recommends keeping wine intended for aging in a cool area with a constant temperature around 55 °F (13 °C). Wine can be stored at temperatures as high as 69 °F (21 °C) without long-term negative effect. Professor Cornelius Ough of the University of California, Davis believes that wine can be exposed to temperatures as high as 120 °F (49 °C) for a few hours and not be damaged.
Orientation of the bottle
Most wine racks are designed to allow a wine to be stored on its side. The thinking behind this orientation is that the cork is more likely to stay moist and not dry out if it is kept in constant contact with the wine. Some wineries package their wines upside down in the box for much the same reason. Research in the late 1990s suggested that the ideal orientation for wine bottles is at a slight angle, rather than completely horizontal. This allows the cork to maintain partial contact with the wine in order to stay damp but also keeps the air bubble formed by a wine’s ullage at the top rather than in the middle of the bottle if the wine is lying on its side. Keeping the ullage near the top, it has been argued, allows for a slower and more gradual oxidation and maturation process. This is because the air bubble that is the ullage space expands and contracts depending on temperature fluctuation. When exposed to higher temperatures the bubble expands, and if the wine is tilted at an angle, this expansion will diffuse through the cork and not harm the wine. If the wine is completely on its side then this expansion will cause the bubble located in the middle of the bottle to push toward the cork, ejecting some wine in the process. When temperatures drop, the bubble contracts and forms a vacuum that brings more oxygen into the wine, speeding up the oxidation process.
Alternative wine closures
Storing wine that is bottled with alternative wine closures other than cork have many of the same considerations in regards to temperature and light sensitivity. While humidity and concerns about oxidation are not as pronounced, the relative recent popularity and increased usage of these closures have not given much opportunity for much research into the storage and aging potential of wines that use these closures.
Places to store wine
Since the end of the 20th century, there has been growth in industries relating to wine storage. Some wine connoisseurs may elect to store their wine at home in a dedicated room or closet. Other options involve purchases and rentals at off-site wine storage facilities that are specifically designed for the task. Some of these industries focus on the construction of home wine cellars and wine caves, small rooms or spaces in which to store wine. Others produce smaller wine accessories, such as racks and wine refrigerators. These appliances can feature adjustable temperature interfaces, two chambers for red and white wines, and materials which protect the wine from the sun and ambient environment.
Purists may cringe and baulk. But can they ignore the acceptance of champagne cocktails world over? The drink that is synonymous with French aristocracy and luxury, champagne together with its sparkling wine cousins were barely seen to be mixed with other ingredients and drink mixers.
History has witnessed both the highs and lows in the popularity of champagne cocktails. Presently, in India the trend has seemingly caught on, and is on its way up quite rapidly. Awareness is the primary factor to influence the growth. Indians have definitely grown more adventurous with their choice of drinks. The lovers of cocktail typically, would vouch that it adds more zing to the bubbly potion. The concoction serves as a great accompaniment to a relaxing Sunday brunch, or the perfect welcome drink to an enjoyable party.
Craig Edney, a UK-based bar consultant, with Hydromel, in an interview with Ambrosia gives an insight into this bourgeoning trend internationally. He says, “Champagne cocktails have always been popular as they are seen as glamorous and decadent, particularly for special occasions like weddings and birthdays.” He classifies the champagne cocktail in two broad groups. “There are two main varieties of champagne cocktails. First, there are those in which the predominant ingredient is champagne or some type of sparkling wine and served in a flute or champagne saucer, for example the classic champagne cocktail, comprising sugar, angostura bitters, cognac and of course champagne. Then there are cocktails where the champagne or sparkling wine is the finishing touch to the drink, such as the Russian Spring Punch containing vodka, cassis, lime juice, gomme, raspberry puree and finally champagne.”
As there are different varieties of champagnes (Blanc de Blancs and Blanc de Noirs) and sparkling wines available in the market, a question arises: What kinds of champagnes make the best cocktails? Edney informs, “For those cocktails that are predominantly champagne or sparkling wine (as I mentioned earlier) a good quality product, (is to be used) as the main ingredient, the overall taste of the drink will be determined by the sparkling wine used. As for drinks where the sparkling wine is not the main ingredient, the quality is not as important. Something a little less distinctive is best.”
One has to be careful while preparing this drink. Edney highlights some of the important measures. “Both of the varieties of drinks are made by combining the other ingredients, in whatever fashion are called for, and then pouring the champagne or sparkling wine slowly as it is likely that the other ingredients will cause the champagne to fizz up. This will avoid spillage and consequent waste. Ensure that all the ingredients are the freshest possible and that all the ingredients are of a comparable quality. There are some cases where the champagne needs to be layered on top of the drink. This can be done by pouring the champagne down an upturned bar spoon with the disc touching the surface of the drink as would be done when making something like, for instance a B52 cocktail.” (Please note, ‘B52’ is not a champagne cocktail but composed of coffee liqueur, Baileys Irish Cream, and Grand Marnier. The ingredients are poured in such a way one after the other that they separate into three distinctly visible layers, due to the relative densities of the ingredients. Edney used the term to explain how the specific kind of champagne cocktail is to be layered). He mentions that worldwide, champagne cocktails or cocktails made using other sparkling wines are very popular with women, although not exclusively, in the 18 to 30 age group.
There is a mention of champagne cocktails in the first book on bartending, ever published in America in 1862, called ‘How to Mix Drinks; or, the Bon Vivant’s Companion’. Back in the 1920s in Europe, this cocktail was found to be extremely popular among the ‘upper crust’. The classic champagne cocktail was preferred during the Civil War era in the US. It was also chosen by Esquire magazine as one of the top 10 cocktails of 1934. The original champagne cocktail was served in champagne saucers, modeled after French queen Marie Antoinette’s breasts. But they are rarely used now. Champagne served in champagne flutes is better as the shape of the flute doesn’t let the bubbles escape easily.
But in India it is only in recent times that the concoction has found more aficionados. Bangalore-based Aslam Gafoor (49) Chief Operating Officer, Weber Grills India and member of Bangalore Wine Club and Chaine des Rotisseurs, informs, in India, “There are plenty of champagne cocktails that Indians enjoy. Popular among those are, Bellini containing peach, Kir Royale with creme de cassis, Mimosa, Axis Kiss with amaretto and creme de cassis, Champagne Fizz with gin and lemon juice, Buck’s Fizz with orange juice.” Just like in other countries, in India too champagne cocktails are usually served as ‘welcome drinks’ or ‘celebration drinks’ and people move on to other drinks as the party progresses. “Champagne cocktails are a very popular choice on Valentine’s Day, something like plain champagne with strawberry has many takers here. Champagne cocktails are also usually liked by younger folks and particularly women,” informs Aslam.
Try out the following recipes of champagne cocktails. In the classic champagne cocktails, the bitters and brandy add warmth to the champagne. Good champagne contributes to the taste and flavour. In all champagne cocktails, champagnes are added last, right before serving for best results.
Ingredients of a Classic champagne cocktail includes one sugar cube, two to three Angostura bitters, a good quality champagne, 30 ml of brandy, orange slice for garnish, maraschino cherry for garnish.
Place the sugar cube in the bottom of a champagne flute. Add the Angostura bitters. Then add the brandy. And fill the champagne flute with champagne. Finally, garnish with the orange slice and cherry. Another simple variation you might like to try out. Here goes. Add four drops of Angostura Bitters to a sugar cube in a champagne flute. Pour some brandy and top up with champagne. As you sip it slow and easy you will be able to taste a sensation changing from dry to sweet.
Kir Royal is another traditional favourite. Simply add champagne to crème de cassis, and get a luxurious and tantalizing aperitif. True to its name, Disco Fizz makes another exciting cocktail drink. An electric blue cocktail, the drink comprises blue curacao, elderflower cordial, pineapple juice and lemon juice in small measures all going in to a champagne flute. And finally, top up with champagne.
You don’t need a reason to party now, do you? Now next time don’t wait for an occasion to pop a bottle of bubbly and fill in your champagne flute. Just make sure you add some ingredients to double the fun.
Although there is some historical evidence suggesting that cork was used as a stopper about 2,000 years ago, its use became more prevalent with the introduction of glass bottles in the 17th century. In recent years, other alternatives such as capsules and plastic stoppers have been introduced as closures for wine bottles. However, cork still remains the principal closure of choice for premium wines. – Writes Rajiv Seth
Cork - an introduction
Cork is essentially a piece of bark from an oak tree known as cork oak, Quercus suber. The cork tree grows naturally in a region bordering the western Mediterranean Sea. The major cork producing countries include Portugal, Spain, France, and Italy in Europe; and Morocco, Algeria, and Tunisia in Africa. Several efforts have been made to grow this species in other parts of the world; but, so far, the results have not been encouraging. Worldwide production of cork is estimated to be 3,075,000 tons. Of this amount, Portugal produces the lion's share (about 55%).
Why use Cork as a Wine closure
Cork is a unique substance and a long proven closure for wines. The cork possesses many remarkable qualities which make it an ideal stopper for wine bottles. Some of the important qualities include: compressibility, resilience, impermeability to liquids, low density, little tendency to rot, and a high coefficient of friction.
Cork is highly compressible. It can be compressed without causing significant lateral expansion. It is also very resilient. After compression, the cork can return to 85% of its original volume in about 20 minutes, and about 95% of its volume after 24 hours. During corking, a cylindrical cork 38 to 40 mm long and 23 to 25 mm in diameter is inserted in a bottle with a bore size of about 18 mm. In this situation, the cork diameter is reduced by 25% (from 24 mm to 18 mm) and the cork volume is reduced by 40 to 50%. Due to its elastic nature, the cork exerts a pressure of 1.5 to 3 kg/cm2 against the glass surface (in the neck of the bottle) and forms an excellent seal. The elastic property of the cork is due to the unique cell structure. As noted earlier, the tiny cork cells are filled with air and thus the tissue can be envisioned as layers of tiny air cushions grouped together. The cork is very light in density (0.12 to 0.25 g/cm3) and a little over 50% of the cork volume is air. When the cork is squeezed (as during corking), the air inside the cells is compressed. The compressed air inside the tiny cells exerts counter pressure which permits the cork tissue to expand and provide an effective seal. With prolonged compression, the gas inside the cells gradually permeates out and the resiliency of the cork is permanently lost; the cork is not as elastic as it was before compression. This phenomenon can be observed when a cork from an old bottle (10 to 15 years storage) is withdrawn.
The elastic property of the cork is influenced by its moisture content. The cork remains fairly elastic for insertion into the bottle within a moisture content range of 5 to 12%. But the moisture content is maintained around the 5 to 7% level in order to discourage microbial growth. Cork is practically impermeable to liquids. This is because the cork tissue is made of tightly packed cells; this leaves practically no room for liquid to pass. One millimeter thick cork tissue may have as much as 30 layers of cells. The waxy and suberous composition of the cell wall makes it even more difficult for liquid or gasses to pass.
Another unique and highly desirable property of cork is its high coefficient of friction. This means that it does not slide easily on smooth surfaces such as glass. The cut surface of the cork consists of broken cells that act like suction cups when they are in contact with the glass. Due to this tendency, the cork adheres tightly to the glass surface (this is what makes it hard to remove the cork from the bottle), and also assumes the shape of the neck of the bottle. In spite of small irregularities in the neck of the bottle, the cork fits well and provides an effective seal.
Cork is a very durable stopper. When in contact with wine, it does not readily degrade. In most cases, very little wine penetrates into the cork and few cork constituents leak into the wine (this assumes good cork). Occasionally, vanillin/woody odors may be imparted to the wine, but overall, it doesn't affect the wine flavor.
How Corks are made
As noted earlier, cork is produced from the bark of a cork oak tree. The cork tree is unique; in that, a careful removal of the bark does not harm the tree and secondly, after stripping the bark, a new bark is regenerated. Although the cork tree is a forest species, it does require some care and attention in order to produce high quality cork bark over a long period of time.
The stripping of the bark begins in summer, usually in July. After the bark is peeled off, the tree produces a reddish fluid which protects the mother bark. The fluid dries to a thin layer and by early autumn, new cork cells begin to form. The first stripping of the bark occurs when a young tree is about 15 to 30 years old and has attained a trunk diameter of 70 cm. The bark that is removed for the first time is known as virgin cork. Its structure is irregular, it is relatively hard (not supple), and is not useful for cork stopper production. This virgin cork is used for producing other cork-based materials.
After a period of about nine years from the first stripping, the bark is removed again. The cork bark removed for the second time is called second bark, and is still not considered good enough to produce cork stoppers. The cork bark that is removed in the third and subsequent stripping is called reproduction cork. Its texture is more uniform and it provides excellent material for producing cork stoppers. Usually the cork quality is considered best when a tree is about 50 years old. The tree will live and produce cork until it is 160 to 180 years old. But after about 100 years, the quality of the cork declines. The stripping of cork is done every nine years. This allows enough time for a tree to grow and produce good sized bark. Starting at 25 years, a tree will yield about 15 stripping.
The stripped bark, also called cork slabs or cork planks, is stacked in piles outdoors. This allows the cork slabs to season or cure. During this period, the sap from the bark dries off and the cork planks undergo weather-induced chemical changes. Following curing, the cork planks are subjected to a boiling process which cleans and disinfects them and also makes the cork planks softer and more flexible. This is important because it allows the semi-cylindrical cork planks to be made into flat slabs called cork board.
In the next step, the cork board is cut into strips. The width of the strip is slightly greater than the length of the cork. The strips are placed on their side and the cork is punched out perpendicular to that of the cork growth. This ensures that the lenticels are positioned on the side of the cork touching the glass when the cork is inserted in the bottle. This reduces the potential leakage of wine through the lenticels.
Cork punching requires great skill in order to maximize the quality and quantity of the corks produced. It is estimated that about 30% of the cork board is used in making cork stoppers. After punching, the corks are polished and the edges are trimmed, if needed. Corks with edges trimmed at 45° are called champerd corks. Some winemakers prefer champerd corks because champering makes it easier to insert the cork during corking. Corks used for fortified wines are made by gluing or binding the plastic top to the end of the cork. Such corks are referred to as T-corks.
After polishing, the corks are rinsed with water to remove dust and treated with a solution of calcium hypochlorite and oxalic acid, followed by a final rinse. The process bleaches and disinfects the cork surface. Since chlorine treatment can contribute to the formation of 2, 4, 6-trichloroanisol, a compound known for causing cork taint, an alternative treatment is preferred.
Instead of chemical treatments, some cork producers sterilize corks by exposing them to irradiation. The process is very effective in eliminating microorganisms such as molds and bacteria. Cobalt-60 isotope (radioactive cobalt) emits gamma rays which can penetrate deep into the cork. This achieves the destruction of harmful microbes both on the surface, as well as, inside the cork.
Following chemical sterilization, the corks are dried to bring the moisture content between 6 to 8%, and then graded. Based on the customer's request, the corks are branded and/or surface treated with silicon or paraffin. Coated corks are often used in high speed bottling. Finally, the corks are packaged in plastic bags containing sulfur dioxide and stored at a temperature of 15 to 20°C and 50 to 70% humidity.
Agglomerate cork or composition cork is another kind of cork used sometimes by the wine industry. It is important to note that the agglomerate cork has a low compressibility and is less elastic;
Champagne corks are a type of composition cork. They are larger than the corks used to stopper still table wines. The upper section of the cork is made of cork particles (like agglomerate cork) and the lower section has two cork disks glued to it. The lower end is in contact with the wine when the cork is inserted into the bottle. Champagne corks must be able to withstand high pressure (about six atmospheres). To achieve this, corks with larger diameters (31 mm instead of 24 mm) are used and they are compressed to a greater degree than table wine corks. For example, the regular corks when compressed are reduced in volume by 45 to 50%. In the case of champagne corks, the volume is reduced by 65%. This provides an effective seal and holds the wine in the bottle under high pressure. Large single piece corks are available for stoppering champagne bottles.
Cork Faults and Quality Control
Cork Defects - A defective cork can cause problems such as leaking. formation of deposits or sediment, and equally important, the development of cork taints. To prevent these problems the vintner should recognize faulty corks and avoid using them. Cork defects can be serious; that is, they can cause leakage and/or make cork insertion difficult. These are defined as critical defects. Other flaws may not be as problematic. They may be related to the appearance of the cork rather than the function. Such defects are considered noncritical. Some of the critical defects are given below.
1. Green wood - This is caused by immature cork cells. The flaw is considered critical if more than 50% of the cork length is made of green wood.
2. Poor cork ends - They are caused by holes, cracks, and/or fissures. If the hole or crack is over one-third the length of the cork, it is a serious flaw. The holes can also be caused by worms. Such corks should not be used.
3. Holes - The presence of any large holes (>2 mm) is considered a critical defect, especially if they are connected together over 50% of the cork length. The holes can be due to insect damage or a large number of lenticels.
4. Belly spots or cuts - These are surface depressions caused by the inner density of the cork or by poor cutting of the cork cylinder. The defect is critical when the spots occur over 50% of the cork's length.
5. Woody corks - This condition results when a cork is cut too close to the bark surface. If over 50% of the cork is woody, it is a serious flaw.
6. Chips, breaks and cracks - This kind of damage usually occurs during the processing of corks. A dry cork is also prone to chipping and cracking. Larger chipped areas or a crack on the cork surface is a serious defect.
7. Poor or improper surface coating - The cork surface is often coated with paraffin, waxes, silicon, and other polymer coatings. The purpose of surface treatment is to make dry corking and cork extraction easier, and also to improve impermeability. When the coating is done improperly, it can cause problems during corking or in forming an effective seal.
8. Dimensions not in accordance with designated size - Incorrect cutting can result in corks that are smaller than the intended size.
Other problems associated with corks are sediment and off odors. Cork dust can sometimes be a source of unsightly deposits. The dust is produced during processing and can be located in large lenticels. Usually coating the cork prevents the dust from getting into the wine.
Cork taint or must and moldy odors can sometimes be imparted to a wine by a defective cork. There are many compounds which are associated with corky (musty and moldy) odors. Most important of these compounds is 2, 4, 6-trichloroanisol. When this compound gets into the wine, it imparts an off odor. It should be noted that this compound can get into the wine from various other sources.
So that's it the Journey of cork immortal from Bark to Bottle, surviving the extreme summers, frequent fires and onslaughts of modern technology, with ever changing scientific perceptions.
Rajiv Seth is a wine educationist, Author and an expert in International Wine Legislation especially European Union. In 1987, he became the first Indian to be awarded a gold medal from WSET, London. He also writes for DelWine. Contact him at email@example.com .