There's Champagne wine, the Champagne region in France, and, I suppose champagne, the colour, if those adverts for paint are to be believed. This writeup is about the wine.
Usually, Champagne (the wine) is an expensive, slightly acidic, fizzy white wine. However, some Champagne wines are still (no fizz), others are only slightly fizzy (petillant or crémant) while others vary in style from brut (dry) to demi-sec (sweet). Most champagne comes out of the bottle a pale straw colour, though older wines may be a much darker gold, and some are made to be pink (rosé).
True Champagne is made only in a designated part of the Champagne region in France. This region is centred on Reims and Épernay, about 150 km north-east of Paris. Most of the rules surrounding the manufacture, labelling and sale of Champagnes are governed by the Appellation d'Origine Contrôlée (AOC) of Champagne, written in 1927. This, along with the name 'Champagne' is defended by the Comité Interprofessionnel du Vin de Champagne (CIVC), a trade association representing all the Champagne houses and growers.
Other sparkling wines, according to the CIVC, may not legally be called Champagne, but may use the style 'Methode Champenoise', or 'Methode Traditionelle' if they are made according to the same methods as 'real' champagne.
Nowadays, a good Methode Champenoise fizz often tastes better and is less expensive than many 'true' Champagnes. On the other hand, some cheap, owner-produced Champagnes can be excellent, while some of the so-called Grand Marque Champagnes can be thin and excessively acidic. In recognition of this, many of the larger Champagne Houses have set up vineyards and wine production centres in California, Australia and New Zealand, in an attempt to prevent the leakage of sales from these newer, high quality producers, and to restore a bit of credibility to the name.
Most true Champagne is non-vintage (often designated NV on the labelling), which means the wine in the bottle is a blend of cheaper and more expensive wines from different years. Individual Champagne Houses strive to pick the blend to give a consistent taste from year to year. About one year in three is declared a vintage year, and the growers may use grapes from that year alone to make a vintage wine, defined by the year in which the grapes ripened. Unlike wines from Bordeaux or Burgundy, there is no real need to remember the individual vintages. Any vintage champagne should be from a good year, though some vintages are certainly better than others.
Some of the better-known champagne houses make extra-special wines in vintage years, packaged in bottles of exotic shapes and colours, called special cuvée wines (cuvée de prestige). These are expensive, even by the standards of vintage champagne, and are claimed to have extra depth, strength or vivacity. You pays your money and takes your choice
Champagne production starts with the terroir, and the grapes grown in that thin, chalky soil. Then there is the initial vinification, followed by the second fermentation, some special procedures, and finally the packaging and marketing. All of these elements are vital to the Champagne story.
Terroir
Terroir is the French word for local vine-growing conditions. It combines meanings of geography, top-soil, sub-soil, microclimate and geology, all of which affect the quality of the grapes. The current AOC Champagne covers 34 000 ha. The whole region is close to the northernmost limit of vine viability in Europe, and the best terroirs are based on chalk slopes, which ensure thin soil and good irrigation. The whole area has been divided into 260 000 parcels of land, each with its own name, many of which have existed for centuries.
Grapes
The AOC permits only three types of grapes to contribute to Champagne wine:
Pinot Noir: (dark red/black grapes, white juice). This is the grape of the best Burgundy red wines and gives structure and strength to a wine, with hints of red fruits. Grown mainly on the slopes of the Mountain of Reims and in the Côtes des Bar
Pinot Meunier: (dark red/black grapes, white juice). This is primarily used to give fruitiness. The wines develops quickly over time, so tends to be used in blends, but adds roundness to more expensive wines. It is grown mainly in the Marne Valley
Chardonnay: (pale yellow grapes) This is the key grape for the best Burgundy white wines, including the Montrachet and Chablis. It is a subtle grape which takes many years to mature fully. It offers floral elements, but can contribute mineral flavours. It is grown in the region known as the Côte des Blancs, between Épernay in the north, to the slopes around the town of Sézanne
Vinification
Initially, the wine is made like any other. Grapes are pickedin Champagne the picking is done by hand, rather than using a machine. This adds to the expense, but makes for a better product, according to the CIVC. The grapes are then pressed to remove the juice and the juice is fermented. White wine made from red grapes (Blanc de noirs) is made by separating the juice from the grape skins before the red pigments in the skins have time to affect the pale juice. Rosé Champagne is made with the same juice, but ordinary red wine is used in the blend at a later stage to give the pink colour.
The CIVC claims that the technique of extracting the pale juice from the dark grapes produces a wine of unsurpassed clarity and purity.
Second fermentation
History has it that the fizz in Champagne was created by a monk called Dom Pierre Pérignon (1638-1715). While the CIVC does not directly mention Dom Pérignon, it does say that Champagne wines did not have any fizz until the end of the 17th century, when the sparkle was introduced. Their version is that the winters are so cold in the Champagne region, that all fermentation stops before the yeasts have eaten the sugars and turned them to alcohol. The second fermentation starts naturally in Spring as the wines warm up once more. If the young wine is stored in wooden barrels, this makes no difference, but if the wine is bottled over the winter, then a second fermentation takes place in the bottle, yielding the sparkle.
Nowadays, the wine is maintained at a controlled temperature, and after the initial fermentation, the wine is bottled, together with a shot of yeast and sugar. Over the next few months the wine bottles are gradually inverted and rotated, so that the yeast and residues gather at the open end of the bottle. The top of the bottle, together with the residue is then frozen solid, and the residue removed. The bottle is topped up with more wine and sometimes sugar (called the dosage), before being closed with a cork and sealed with a retaining wire.
Update: 14 Dec. 2005. The process of removing the yeast residues following second fermentation is quite sensitive, and needs to be carefully controlled. The top of the bottle is dipped in liquid nitrogen to a pre-determined depth, for a carefully controlled time. During this time, the top few centimetres of wine, containing all the yeasts and residues freezes solid. Adjacent to this volume of solid wine, there is an area of mush which is almost -- but not quite -- frozen. In addition, the temporary seal (usually a crown cap) has some geometrical features that bond mechanically to the ice. After the pre-specified time in the freezing dip, the crown cap is removed, and -- thanks to the funny geometry -- that brings a plug of wine and residue with it. However, there is enough strength in the remaining ice to contain the pressure built up by the second fermentation. It is the necessity to retain the pressure, while releasing the yeast residues that is so sensitive to the amount of freezing involved.
The dosage is then added, to top up the bottle and to adjust the sweetness and colour of the final wine. Brut wines have no sugar added, while demi-sec wines have enough sugar to make them quite sweet. Rosé wines -- which may be dry or sweet -- use red wine for the dosage.
As dwardu notes below, the cork starts its life as a fat cylinder. It is forced into a bottle-neck-shaped die to reduce the diameter, and this squished cork is then forced into the bottle. As soon as the die is released, the top part of the cork expands to its original size, while the lower part of the cork is constrained by the bottle. All the wires and foil are then applied around the cork. Once the wine is opened, the cork comes out of the bottle, and the lower part of the cork expands once more, creating the familiar mushroom-shaped cork.
Bottle sizes
half-bottle (37,5cl),
bottle (75cl),
magnum (2 bottles / 1.5litre),
jeroboam (4 bottles / 3 litres),
methuselah (8 bottles / 6 litres),
salmanazar (12 bottles / 9 litres),
balthazar (16 bottles / 12 litres)
Still wines
Because of the high added value of the fizzy Champagne, relatively few still wines are produced, but a few producers make Coteaux Champenois in white, red and rosé styles
Champagne Houses
Although the Champagne Houses wield a lot of power in the Champagne industry, few of them own large vineyards, preferring instead to buy in grapes from the vineyard owners. These are the top houses, though some of them produce only small quantities, destined for consumption in France.
This piece written, formatted and edited in Dann's E2 offline scratchpad
Sources
http://www.champagne.fr
France Wine Atlas by Hugh Johnson
My own knowledge and experience -hic-