Champagne and Sparkling Wine Production
The traditional method is the method used for production in the Champagne Region of France. It is also used to produce sparkling wine in other parts of the world. Refer to our Sparkling Wine Production report for a brief overview of the traditional method as well as a description of other sparkling wine production methods.
The traditional method can be briefly summarized in three broad stages. The initial part of the process involves making a basic still wine. Next, there is a blending phase, or assemblage, where the winemaker mixes various still wines, possibly from different grape varieties, different harvest years and/or different harvest plots. Finally, there is the phase that makes the blended wine 'sparkle' through fermentation in the bottle. These steps sum up the overall process, but there is much more to it than that.
While there are several methods for producing sparkling wine, the traditional method is undoubtedly one of the most complex winemaking progressions of all. There are variations in the process and in the costs involved depending on the style of sparkling wine to be produced. However, the basic principles involved with the traditional method remain the same, whether the product will be a Cava from Spain, a traditional sparkling from California, or a champagne from, well, Champagne, etc. To get a true understanding of the intricacies involved, the method must be separated into several steps beginning just after grape harvest. The following information focuses on customary practices used in Champagne - the Method Champenoise.
Grapes are picked by hand and pressed in whole bunches quickly but gently just after harvest. This helps minimize any skin contact that would possibly add undesirable color and tannin to the juice. Various presses are used including the original 17th century coquard press. Different presses have been designed recently that promote desirable aspects of individual winemakers such as inert presses to minimize oxidation, but it is amazing that the newest technology still incorporates many of the elements from the original coquard press. During the pressing, only 2550 liters of juice per 4000 kilograms (8820 pounds) of grapes are allowed for champagne production by law. The first press is called vin de cuvée (tête de cuvée or head of the cuvée). This press includes the first 2050 liters of juice (542 gallons). The second press is the taille allowing the next 500 liters (132 gallons) of juice. The juice from these 2 pressings are generally processed separated. Many winemakers in Champagne only use the first 2050 liters and sell the taille. As techniques improve and the quality of taille advances, more winemakers are considering incorporation it into the final wine. After the first and second press, there is a final press called the rebeche, but as prescribed by law in Champagne, the resulting juice may only be used for distillate or vinegar and cannot be used for champagne production.
After pressing, batches go through a settling/clarification process called debourbage to remove remaining solids. The juice rests at cool temperature for several hours and the clear juice is racked or siphoned off leaving the solids on the bottom. Each batch is tracked individually by variety, date and time of harvest, vineyard of origin and sometimes even vineyard plot. The tracking takes place throughout the pressing and base wine vinification process.
2. Primary Fermentation
Primary fermentation to make still wine takes place at about 64 to 68 degrees Fahrenheit (but can range from 60 to 75 degrees depending on the preferences of the winemaker). The fermentation vessel also varies from stainless steel to concrete to oak vats or smaller oak barrels. Each batch is fermented separately and the variables continue to be tracked. The resulting wine is high acid and has approximately 11% alcohol by volume. After primary fermentation, many wines go through malolactic fermentation. 'MLF' is not actually a fermentation per say, but a process where bacteria convert hard (green apple like) malic acid to softer (milk like) lactic acid, lowering overall acidity. Most producers include malolactic fermentation in the process but some do not, preferring to emphasize the fruit and the acidity.
3. Aging the Still Wine
At the end of the primary fermentation (and MLF if it is included in the process), the wines are sometimes clarified by either filtering, fining or centrifugation. Other producers may leave the still wine to age on the lees (dead yeast cells) to add complexity. Sometimes the wines are stirred in their storage containers to enhance the wine's contact with the lees. This process is called batonnage. Winemakers store these wines in various containers including oak (old or relatively new) for various lengths of time depending on the desired style.
4. Assemblage / Blending
The final wines are kept in storage until after the first of the year following the harvest. Reserve wines may be stored for future blends for many years. At the beginning of the year (January or February) through March or so, the 'Chef de Caves' (leading cellar master/winemaker) begins the process of assemblage or blending. Perfecting the practice of assemblage is truly considered an art. Large Houses may have a panel of specialists that will taste many base wines. The number of wines available for analysis may reach into the hundreds and include the batches from the latest harvest plus numerous reserve wines from previous vintages (some may be 15 years old or more). The difference between assemblage of a non-vintage and a vintage is the vintage in Champagne is limited to grapes harvested in the vintage year and must be 100% from that year. It is a legal requirement that 15% of each year's harvest must be set aside as non-vintage even if a vintage is declared. A non-vintage can benefit from the addition of reserve wine of different vintages. The goal is to find the perfect mix with the sum being of superior quality than that of the individual components.
For a non-vintage there is also a goal of maintaining consistency from year to year. The foundation for the non-vintage wines are base wines from the latest harvest. The amount of reserve wine used in a non-vintage wine can vary from as little as 0% (with only the latest vintage being used, which is acceptable) to as much as 50% (with as many as 6 or 7 previous vintages added). This process requires a great deal of talent and dedication as the panel and the Chef de Caves taste through many wines from different grape varieties (Pinot Noir, Pinot Meunier and Chardonnay), different years, different fractions (vin de cuvée or taille), different villages (cru) and in some cases even different parcels that have all been vinified separately. During the selection, tasters must continually envision an end product that will go through several more steps before the ultimate goal is achieved. For rose' wine, a portion of still red wine is usually added to the blend, although a few producers actually use skin maceration before the primary fermentation to achieve the rose' color. Champagne is the only wine in France that allows blending red wine to achieve a pink color. All others, still and sparkling from other areas, achieve the pink color through a short skin maceration with red grapes.
5. Liqueur de Tirage / Addition of Sugar and Yeast and Bottling.
After the assemblage is complete, the wine typically goes through a cold stabilization and/or fining process to clarify the final blend. Cold stabilization crystallizes tartaric acid to prevent crystallization in the final product. Then a mixture called the "liqueur de tirage", consisting of sugar, nutrients and yeast, is added to the assemblage. The wine is bottled in especially strong glass bottles and typically sealed with a crown cap similar to that on a soda bottle. These special caps have a small plastic cup attached, called a bidule, that will catch sediment. These caps may be engineered to include some degree of oxygen permeability as desired by the producer. Producers may rarely chose natural cork as a seal if they plan to age the wine on the lees for an extended period of time.
6. Secondary Fermentation
The secondary fermentation, often called the 'prise de mousse' or 'capturing the sparkle' commences at a cooler temperature, typically between 50 and 54 degrees Fahrenheit. This fermentation generally lasts for about 2 weeks to 3 months. The cooler the fermentation, the longer the process will take. At the end of the secondary bottle fermentation, after all the sugar has been consumed, the yeasts die and decompose. This fermentation will increase the alcohol by volume to about 12 or 12.5%.
7. Aging on the Lees
When the secondary bottle fermentation has ended, bottles are moved to appropriate storage areas for aging on the dead, decomposing yeast cells (the lees). Some producers store the bottles in riddling racks (pupitres) or gyropalates in preparation for the next step (remuage or riddling). Others store in stacks, several rows deep, consisting of hundreds and even thousands of bottles. The bottles are typically stored in the Champagne House's cellars: vast dark underground caves excavated deep into the chalky limestone, some dating back as far as the Gallo-Roman era. Some houses disassemble and rebuild their stacks, shaking up the bottles during the process to enhance the lees contact during aging. Wine stored in gyropalates can be mechanically shaken periodically to accomplish the same task.
The caves maintain a constant temperature of around 54 degrees Fahrenheit. The temperature, humidity and darkness are the perfect environment for autolysis, the enzymatic breakdown of the yeast over time. The bottles are stored horizontally to maximize the lees contact. Rows stored in stacks are often separated by wooden lathes. Wines stored in this horizontal position are referred to as 'vins sur lattes'. The required legal storage time is 15 months including a minimum of 12 months on the lees for non-vintage champagne. Vintage champagne must be aged for 3 years. Most houses, especially the large producers, age their bottles significantly longer than the legally required time to maximize autolysis effects and ensure appropriate maturation. Studies have shown that the most active time for autolysis appears to be about 18 months continuing for up to 5 years, with a slower progression for several additional years. For champagne and other wine that is aged on the lees, autolysis provides complexity and is often associated with biscuity, bread dough, brioche notes. There is also a small amount of oxidation occurring during the process that contributes to the maturation, depending on the type of cap closure the Chef de Cave and his team have selected.
The Spanish developed an automated technique to accomplish the task in the 1970s with the invention of the girasol. The French tweaked the process and today the computerized gyropalette is widely used. The devices are computerized and reproduce the effects of manual remuage, but with much less labor and time. Manual remuage takes about 4 to 6 weeks whereas automated remuage with a gyropalette takes four days or less to complete. Many small producers still use manual remuage. There are also a few large houses that manually riddle all their wine, but in general, with the exception of some high end, vintage or prestige cuvée, most remuage is now accomplished through the automated process.
There are also special encapsulated yeasts that do not stick to the glass walls of the bottles that have been developed. They expedite the process, but currently they are not widely used for champagne production.
Originally the disgorgement was called 'degorgement a la volée'. The bottle, in the upside down vertical (sur pointe) position with sediment in the neck, was manually uncapped and quickly inverted to allow the sediment plug to be expelled, trying to minimize the loss of wine. This method is occasionally practiced in some small houses today but has largely been replaced by 'degorgement a la glace' which involves placing the sur pointe bottle neck in a shallow freezing solution of liquid nitrogen, glycol, brine, etc. The sediment plug is semi-frozen to the point that the bottle may be inverted before the plug is expelled. In this semi solid frozen state, the plug remains trapped in the neck during the upright inversion. The pressure from the CO2 in the wine propels the sediment plug out of the bottle, but the freezing temperature of the plug subdues the internal pressure enough that there is little loss of the wine. The bottle is then topped up with the Liqueur d' Expedition, and re-stoppered.
10. Liqueur d' Expedition / Dosage
After disgorgement a mixture of wine and sugar, the dosage or "liqueur de expedition", is added to provide the desired amount of residual sugar to the wine. This is done to top up the bottle, replacing the volume lost during disgorgement. It also serves to balance the high acidity in the wine. Wines with greater acidity generally require a higher dosage to achieve balance. Wines that are stored on the lees for longer periods of time prior to disgorgement require a smaller dosage since longer aging tends to balance the acidity and sugar. A wine that is designated as Brut Nature, Zero Dosage or Brut Zero has no residual sugar added through dosage. Cellaring for a period of time after purchase by the consumer will also help balance champagne with high levels of acidity. Some wines are produced to have more sweetness and will be given a higher dosage. Refer to the Champagne Sweetness Levels webpage for more information on the amount of residual sugar in different sweetness types of champagne.
When the appropriate dosage has been introduced, a stopper is quickly added. Traditionally the stopper was natural cork but it has evolved into a cork with a top composed of agglomerated cork with two round disks of natural cork glued to the bottom. The cork has straight edges but is fatter than the corks for still wine. Technical advancements continue today with more and more producers choosing DIAM cork instead of natural cork. Mytik DIAM is a patented 'technical' cork made by combining tiny granules of cleaned cork with synthetic microspheres. This is considered a true quality improvement as it minimizes faults such as Trichloroanisole (TCA or 'corked wine') that occasionally occur with natural cork. The corking process itself consists of passing bottles through a corking machine which compresses the cork and inserts it about half way into the bottle. The cork is secured with a metal cap and wire cage. The bottle is agitated to homogeneously blend the dosage with the wine.