History of Sparkling Wine

Sparkling wine’s development is also Champagne’s development. The story starts with the “Little Ice Age” which caused Northern Hemisphere temperatures to decrease from the late 1400s to the mid-19th century1.  In turn, this caused issues with complete fermentations, and when the weather warmed in the spring, the already-casked wine would start refermenting, causing the accumulation of carbon dioxide (CO2) within the vessel. This effervescence was considered a wine fault at first.  However in the 1660s, a few significant and unrelated events occurred: 

In France:

• 1668: The Catholic Church, which had major investments in Champagne vineyards, assigns Dom Pierre Pérignon to Hautvillers Abbey to eliminate the effervescence in Champagne wine. 
• Sparkling wines were introduced to the court of Versailles by Pierre Brûlart, the Marquis de Sillery during the reign of Louis XIV (1643 - 1715)

In England:

• 1662: Christopher Merret presented a paper on making sparkling wine to the Royal Society.
• Charles de Saint-Évremond (1614-1703), a Frenchman and the first true ambassador for Champagne, fueled its popularity in England during the late 1600s at the court of Charles II. (domaineevremond.com)

By the end of the 17th century, Dom Pérignon was ordered to reverse his efforts and was tasked with developing new ways to increase bubbles, which included the usage of cork instead of rags or wooden pegs.

According to the Oxford Companion of Wine by Jancis Robinson and Julia Harding, throughout the 18th century only a few thousand sparkling wine bottles were produced every year, and half of them would break because the fermentation science was still generally unknown. The current version of Champagne did not exist until the 19th century, aided by the following technological advancements ​​Bottles were made thicker in 1735, as a result of the French copying the English. This was followed by moulding being introduced in 1882 to standardize capacity, then in 1918, glass blowing using compressed air was adopted by the industry.

​Around 1820, Champagne makers started to add rock sugar to their cuvées, to kick-start secondary fermentation. Some years later, wine enthusiast and former Châlons-en-Champagne pharmacist Jean-Baptiste François invented a method to determine the total sugar content in the cuvée. By the late 19th century, scientists had worked out that the addition of 4 grams of sugar/liter raised pressure by 1 bar after fermentation.

In the 1850s, Madame Veuve Clicquot and her employees developed the system of pupitres (wooden frames) to assist the remuage process (turning or shaking of bottled Champagne to move sediment toward the cork). The corking machine was developed, and the understanding of secondary fermentation by Jean-Baptiste François enabled winemakers to measure the precise quantity of sugar required to induce a second fermentation without an explosive force.  
​
It was not until 1892 that the traditional method arrived in Spain, and in 1924, Prosecco got its bubbles via the Charmat method, a process that traps bubbles in wine via carbonation in large steel tanks.

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Harvest and Primary Fermentation

Grape Cultivars

• Grape Cultivars
• Grape Ripeness

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Both white and red grapes may be used to produce sparkling wine; however, white grapes are favored for the attributes that also constitute ideal “ripeness”. 
The ideal ripeness of sparkling wine grapes is:

• Sugar: 18 to 22º Brix to yield an ABV of 9-10.5% (Jackson, Wine Science).
• Acidity: Lower pH (2.9 – 3.4) and higher titratable acidity ( 8.0-16.0 g/L) than table wine to provide the signature fresh characteristic of sparkling wines.3
• Aroma Characteristics: Higher acidity often also means less varietal character.

Grapes in cool wine regions are sometimes picked underripe to avoid Botrytis cinerea, a fungus which causes foaming issues. Ripe grapes are ideal, however. In a study by Liu et al. (2018):4 

• Healthy Chardonnay and Pinot Meunier grapes were picked in the Champagne region during the 2015 and 2016 harvest seasons at different maturity levels, with a potential alcohol content (PAC) of 8% –11% v/v, where a PAC of 8% v/v is the lowest permissible ripeness in Champagne, but is not considered to have sufficient sensorial maturity. This low maturity can be compensated by blending with more mature wines from the same or previous vintages. The grape juice and base wines produced from those grapes were examined for protein content, foamability, and oenological parameters. 
• The results showed that base wine protein contents and foamability were higher when the grapes were riper. Strong correlations between maturity degree and most of the oenological parameters in grape juice and base wine were also found for the two cultivars. 

Harvest can be done by machine or manually. 

• Botrytis-infected grapes are rejected because the fungal infection of grapes causes a degradation of proteins in the resulting wine and influences the foaming properties of the wine.5  
• Fruit rupture can cause oxidation of the juice, and excessive pigment and tannin extraction (Jackson, Wine Science). 

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Crushing and Pressing

​Grapes may or may not be crushed, as pressing alone minimizes skin contact and phenolic extraction.  Grape skin tannins and pigments accentuate gushing, the rapid and uncontrolled increase of gas volume that results in the expulsion of foam from a bottle of sparkling wine, because of changes in stability resulting from precipitation of pigment and tannin complexes.6  If grapes are crushed before pressing, unwanted solids may be removed prior to fermentation by bentonite-facilitated settling, centrifugation, or filtration.  Additionally:

• Pressing
• Press Fractions

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Type of Press

• Traditional: Vertical fixed basket press. 
• Typical: Pneumatic mechanical horizontal press. These take up less space than traditional presses and are easier to load and unload.

Styles of Pressing

• Whole cluster pressing (pressed without being destemmed), provides channels for the juice to escape, thereby minimizing the pressure required. It may also help to create early malolactic fermentation, and favors the onset of the second in-bottle yeast fermentation (Jackson, Wine Science).
• Destemming before pressing provides more room in the press. However, this can create less juice unless the pressure is raised, which can cause seeds to break.  

Force of Pressing

• Light pressing minimizes skin phenolic extraction and exposes the grape juice to oxidation which can provide protection against in-bottle oxidative browning as the brown pigments that form can precipitate out during settling or fermentation (Jackson, Wine Science). 
• Some regions specify the maximum force allowed for pressing.

​The juice that results from the pressing process is divided into the following fractions:7

Free-Run Juice/Autopressurage (Champagne)/ Mosto Flor (Cava):  

• Pressure: No pressure, just the weight of the grapes in the press.

The cuvée:  

• Pressure: Light pressure.
• Juice Characteristics: Lowest pH, highest tartaric and malic acid content, rich in sugar.

Première taille/First Taille: 

• Pressure: >100 kPa. 
• Juice Characteristics: Rich in sugar, but has lower acidity and higher fruit aroma, mineral content (especially potassium salts), tannin content and pigment concentrations. 
• Taille musts produce intensely aromatic wines – fruitier in youth than those made from the cuvée, but less age-worthy.

Second Taille:  
Not used in Champagne production and is vinified separately from the cuvée, or distilled (Jeandet, 2011).

After crushing, the juice is chilled and clarified by settling solids, bentonite-facilitated settling, centrifugation, or filtration prior to fermentation.

• Dambrouck et al. (2007) found 10-50 g/hL of bentonite leads to a significant decrease in both total protein content and grape invertase content, which in turn decreases foam height and foam stability. If casein (10 and 20 g/hL) or bentonite combined with casein (both at 20 g/hL) was used, only a slight decrease in the total protein content and grape invertase concentration was found.8  It should be noted that bentonite may impact these proteins at any point during the winemaking process. 

A Traditional Press Images by: Comité Champagne

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Primary Fermentation

• Primary Fermentation
• Malolactic Fermentation
• Maturation/ Clarification/ Stablization
• Blending/Assemblage

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Temperature:

• Approximately 59-64ºF (15-18ºC) which is similar to that of white wine, though it can be as low as 55°F (13°C)9. 
• 65-70ºF reduces floral intensity (Zoecklein, 1998).

Yeast:
Typical white wine yeasts of Saccharomyces cerevisiae as the primary fermenter and Saccharomyces bayanus are also common.  Ideal strains help to minimize the production of SO2, acetaldehyde, acetic acid and other undesired volatiles created by indigenous yeasts (Jackson, Wine Science).

pH

• Range: pH of 2.90 – 3.2010 with 3.1 -3.4 being favorable to malolactic fermentation. [11] 
• Adjustment: Deacidification through malolactic fermentation or sterile filtration (to enhance aging potential).

Additives commonly used to adjust the fermentation based upon the maturity of the grapes and proportion of diseased fruit are, according to Jackson, in Wine Science:
SO2, added to the juice as it comes from the press.  

• Sugar for chaptalization.
• Clarifying agents: 
• Bentonite, casein, or a blend of bentonite, potassium caseinate and microcrystalline cellulose may be used to remove excess polyphenolics. 
• Activated carbon, pectinase, and additional sulfur dioxide can be used to remove glucans, pigments, and inactivate laccases released from diseased fruit. 

Malolactic Fermentation
Malolactic fermentation may be used to tame the high acidity of the wine and reduce the amount of dosage sugar required for balance. The process of malolactic fermentation, according to the AWRI 2020 Winemaking Fact Sheet: 

• Can be induced after inoculation with Oenococcus oeni. 
• Occurs before the second, in-bottle fermentation, because the sediment produced is difficult to remove by riddling.
• Minimal SO2 usage and a maturation temperature at or above 18ºC is required for malolactic fermentation. If the wine does not undergo malolactic fermentation, a high amount of SO2 is used. 
• After malolactic fermentation, the wine is clarified by centrifugation, or static settling with the aid of fining agents including: “bentonite, gelatin + [tannins or silica gel], casein + bentonite, charcoal + bentonite, fish gelatins or wheat gluten” (Jeandet et al).

Maturation Process
Duration
Maturation may last for several months to a decade. This depends on the style of wine being produced.

Maturation Temperature
In tanks at 12-13°C (Jeandet et al).

Maturation Container

• Stainless steel is typical and does not allow oxidization.
• Small oak cooperage that is inert allows for oxidization.

Lees Maturation

• Fresh, fruity styles of sparkling wine have no lees maturation.
• In primary fermentation, the lees are composed of tartaric acid salts, organic residues and microorganisms

Clarification and Cold Stabilization
The cuvée is cold stabilized and loose-filtered to remove any tartrate crystals that formed, while still allowing proteins and polysaccharides used in the formation of a fine and stable mousse to remain. This is done to prevent gushing (Cordingley/AWRI, 2020).

Blending/Assemblage
Base wines, which may differ in vineyard, vintage, and cultivar, are blended together to create a cuvée. 

Why:  Blending, created by a formula developed through sensory evaluation of the base wines, is often crucial, because a single year may not have adequate weather to ripen grapes to provide the ideal aroma characteristics, sugar level, or sufficient volume for production. This is more important in cold regions like Champagne, where weather is highly variable.

Vintage vs Non-vintage 
As sparkling wine typically comes from cool climate areas where grapes have higher acidity than corresponding still wine produced from the same cultivar, there can be issues with achieving ideal sugar and potentially phenolic “ripeness”.  

• Non-vintage: To achieve high quality and consistent wine yearly, reserve wine is used.  
• Vintage: In great growing years, the use of reserve wines may be foregone to express the climate of that year.

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Sparkling Rosé Production Process

Sparkling Rosé Production

Sparkling Rosé is typically made in one of two ways:

Rosé d’assemblage: 

• Blending still red wine (10-15%) into the still white wine before secondary fermentation. 
• Produces a lighter style of rosé sparkling wine

Saignée method

• In this common rosé still winemaking process, black-skinned grapes are destemmed and left to macerate for 24-72 hours until the desired color is achieved.  Some of the wine is then bled off (hence the name Saignée), while the remainder of the wine is kept to make still red wine with a higher level of skin contact.
• Produces a more structured style of rosé sparkling wine.

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Prise de Mousse/Secondary Fermentation

The common ways of creating effervescence in wine are: 

•  Méthode champenoise (traditional method)
• Charmat method (tank fermentation
• Force carbonation

In general, European wine regulations require a minimum of 90 days for the secondary aging of effervescent wines.

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Method Champenoise/​The Traditional Method

​Methode champenoise entails adding liqueur de tirage (a liquid solution of yeast, wine and sugar), and a combination of yeast and sugar into a tank containing finished still wine, to produce CO2. The wine is then bottled with a plastic bidule that sits at the neck of the bottle and is used to gather the yeast, and a crown cap (similar to a beer bottle cap, which was first utilized in Champagne in 1960). The bottles are then laid on their sides to maximize surface area exposed to the yeast. Groups of bottles are placed into a riddling rack or a metal cage, called a riddling box, for mechanical riddling for 6-8 weeks in cellars that are a relatively constant temperature, before being disgorged.    

• Liqueur de Tirage
  
• In Bottle Maturation
• Riddling/Remuage 
• Disgorgement
• The Transfer Method

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Liqueur de Tirage
As no fermentable sugars remain after primary fermentation, effervescence is created by adding liqueur de tirage, a solution of 20-24 grams/liter of beet or cane sugar to create an internal bottle pressure of 5-6 atmospheres (atm) [13].  It takes 3.0 to 4.3 grams per liter to increase one liter of wine, 1 atm of CO2 and 1.1-1.5% ABV (Jackson, Wine Science). The following is also added:

Yeast, grown out in a glucose solution or incorporated into a stable gel matrix. The yeast type can vary based upon the parameters of the base wine. For example:

• Saccharomyces bayanus is capable of fermentation under the following conditions: 8-12% ABV, ~10ºC, pH ~2.8, and SO2 of up to 25 mg/liter (Jackson, Wine Science). 
• Saccharomyces uvarum is cold tolerant, however it may produce increased amounts of isoamyl, isobutyl alcohol, and 2-phenyl alcohol [14].  S. uvarum also does not flocculate out well.  At 10°C, the cryotolerant strains also produced more glycerol than S. cerevisiae, but the glycerol is produced in a larger amount at 25°C, whatever yeast is used.

Other nutrients, including nitrogen and copper salts to reduce hydrogen sulfide production, and thiamine, which may counteract alcohol-induced inhibition of sugar uptake by yeast cells (Jackson, Wine Science). 

Duration and Temperature
Duration: ~50 days. This is dependent on the temperature, pH, and sulfur dioxide content of the cuvée.
Temperature: ~12-14ºC, a common fermentation temperature in Champagne (Liger-Belair, 2008).

• Cooler temperatures may result in fermentation terminating early.
• Warmer temperatures may result in a rapid increase in alcohol content, which may prematurely terminate fermentation. 
• Temperature consistency is important to maintain yeast viability under difficult fermentation conditions (Jackson Wine Science).

Maturation on Lees (in bottle)
In secondary fermentation, the lees are predominantly composed of yeast and potentially riddling aids. It lasts longer than still wine aging, and autolysis occurs under pressure (Alexandre, 2006).  In-bottle maturation on the lees is done to create toasty, bready, and umami notes via yeast autolysis (the rupture of yeast cells which causes enzymes to break down proteins into amino acids, oligopeptides, salts and carbohydrates). Autolysis may also increase the stability of the mousse.

Aging Terms

• Sur Lie: Bottles are aged on the lees.
• Sur latte: Bottles are stacked on their sides with or without lees.  Latte refers to thin wooden strips used between the bottle layers.

The Process of Autolysis [15]

1. The restructuring of cell endostructures and the activation of lytic enzymes, which is accompanied by reduction of cell volume and system viscosity.
2. Hydrolysis of cell components and release of hydrolysis products into extracellular space. 

Rate and Duration of Autolysis
The rate of autolysis is influenced by yeast strain, grape variety, temperature of storage, and duration of lees contact.
Duration: 9 months to 10+ years.

• ~3 months (80 days): Cells plasmolyze, and most typical membrane-bound organelles disappear. By the time of disgorgement at 9-12 months, few, if any, viable cells remain (Wine Science/Piton et al., 1988).16 
• 18 months: The optimal duration for effervescence production and foam stability, because of the accumulation of polysaccharides.17 Further aging seems to result in polysaccharide hydrolysis (breakdown).

Maturation Aroma Compounds 
Volatile thiols [18] 
In Champagne: Benzenemethanethiol, 2-Furanmethanethiol, and Ethyl 3-mercaptopropionate were present in these wines at concentrations considerably higher than their perception thresholds. Their concentrations increased gradually in proportion to the bottle aging period and sharply as a result of disgorging.
Flavor attribute: Toasty. 

In Cava, Francioli et al. found that if aged over 20 months age markers included: [19] 

• Vitispiranes (floral fruity) 
• 1,2-dihydro-1,1,6-trimethylnaphthalene (TDN) (Petrol)
• Diethyl succinate (Fruity).

For a great summary on the current literature of sparkling wine yeast autolysis read:
Alexandre, H. and Guilloux-Benatier, M. (2006), Yeast autolysis in sparkling wine – a review. Australian Journal of Grape and Wine Research, 12: 119-127. https://doi.org/10.1111/j.1755-0238.2006.
Source: www.scribd.com/document/78997658/Yeast-Autolysis-in-Sparkling-Wine-A-Review-SUB
 
Additional Aging: Oenothèque (French)/ Enoteca (Italian)/ Vinothek (German): Traditionally meaning wine repository, this term references reserve bottles, ~10-20% of the vintage, that are aged longer in the wine cellar after the initial 80% that is released to the market. This maintains better quality control over the maturation of the bottles which may have otherwise been improperly stored, while also internalizing the profits from the high prices that secondary market fetches for vintage wines. This is also sometimes referred to as vinotheque (vinotheque can also mean that the base wine is aged longer prior to secondary fermentation).

The yeast sediment that accumulated during secondary fermentation is moved into the bidule in the neck of the bottle to be disgorged (removed) via riddling. This can be done manually or mechanically.

Manual riddling

• Wine bottles are stored neck-down at a 30° angle in A-frame racks called pupitres.  
• The sediment is dislodged by turning each bottle an eighth to a quarter  turn by hand.
• Duration: 3 to 8 weeks.

Mechanical riddling

• Wine bottles are stored in riddling cages which are on mechanical gyro pallets.
• The entire riddling cage is turned mechanically and a computer program is used to calculate how much and when to turn each cage.  
• Duration: 5 - 10 days.
• Mechanical riddling minimizes variation between bottles and is significantly less labor intensive and less expensive

Disgorgement: The Removal of  Sediment

​Process

• The bottles are chilled to approximately 7ºC. The neck of the bottle is then placed into an ice bath with calcium dichloride and ice or a glycol solution, which freezes the sediment in the neck of the bottle (Wine Science). 
• After mechanical or traditional disgorgement, additional wine is added because wine is lost during the disgorging process.

Mechanical disgorgement: 
Once the plug is frozen, the bottle is placed onto a conveyor belt, where the machine pops the crown cap off each bottle to eject the plug of frozen yeast, which allows the wine to be shot out the bottle’s neck. For a great video, watch: Jamie Goode’s video How sparkling wine is bottled: a mobile disgorging line www.youtube.com/watch?v=fkyDcE9UT_0 

Traditional disgorgement by hand 
(à la volée): 
The bottle is held upside down before being opened. It is then quickly tilted back upwards so that only enough wine is forced out to take the sediment with it. This technique is still used for very small or very large bottles and very old vintages.

The Transfer Method
The transfer method, which is allowed in some regions except for those that require the traditional method, follows the same process as the traditional method until the point of riddling.. 

Process
After riddling:

• The bottles are disgorged into a sealed and pressurized tank. 
• The wine is filtered to remove the yeast lees.
• Liqueur d'expedition (the liqueur to replace the volume of wine lost) is added and the wine is then rebottled into a fresh bottle. 

Benefit
The transfer method can be more cost-effective than the traditional method, and the utilization of large batches makes it easier to achieve consistency.

Labeling
Typically labeled: “bottle-fermented” rather than “traditional method” or “methode traditionnelle.”

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Bulk fermentation, which utilizes large pressurized tanks or autoclaves, was invented by Federico Martinotti in 1895 and then adapted by Eugene Charmat in 1907 (Prosecco.wine).  It is also referred to as “Cuve Close” which translates from French to “Steel Tank”.

Ideal for: 

• Sweet sparkling wines, because the subtle flavors that are generated by the traditional method would be masked, thereby adding unnecessary expense (Jackson, Wine Science). 
• Production of rosé and red sparkling wines, because grape skin tannins and pigments accentuate gushing, the rapid and uncontrolled increase of gas volume that results in the expulsion of foam from a bottle of sparkling wine.20 
• This may be a cheaper production method for shorter maturation wines. As the autoclaves (pressurized fermentation tanks) are used for long maturation, the cost-saving advantages of the system may be negated, as each tank is expensive.

Primary fermentation 

• Duration: 15-20 days. 
• Temperature: Maximum temperature of 18°C to preserve the most delicate aromas and flavours (prosecco.wine).
• Wine is fermented to ~6% ABV before being chilled to stop fermentation and preserve some residual sugar for the secondary fermentation. 
• The base wines typically undergo malolactic fermentation prior to the second fermentation to reduce acidity.
• Yeast is then removed by filtration and/or centrifugation. 

Secondary fermentation
Cuvée formulation:  Wines are combined in pressurized stainless steel tanks called autoclaves with yeast, additives of ammonia and vitamins, and sugar (if necessary).  

Duration of fermentation: The wine may or may not be aged on the lees for up to 9 months.  If there is extended lees contact, intermittent stirring is used to release amino acids from autolyzed yeast cells and prevent the formation of a thick layer of yeast cells, which can form sulfur taints (Wine Science).  

Stopping Secondary Fermentation

• Cold stabilization is used to precipitate tartrates.
• Yeast is removed through centrifugation or filtration.
• Sugar and SO2 adjustments are made and then the wine is sterile-filtered before being bottled.
• To maintain ideal effervescence, the entire system including bottling must pressurized (isobaric).
• To reduce effervescence, still wine may be added to the sparkling wine before final filtration and bottling.

Carbon Dioxide Pressures
Rosé and red sparkling wines are commonly finished sweet, with low CO2 pressures that vary depending on the specific wine region. They are typically either: 

• Pétillant (naturally sparkling): 7 g CO2/liter)
• Crackling Wine: Sparkling light grape wine normally less effervescent than Champagne or other similar sparkling wine.21 
• White sparkling wine: Typically 12g of CO2/liter minimum

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The Natural Method/ Pétillant naturel/ Méthode Ancestrale [22]

The Natural Method/ Pétillant naturel/
Méthode Ancestrale [22]

​Grapes
Specified by region or winemaker.

Primary Fermentation: 
Typical for white winemaking. However, the wine is bottled while it is still fermenting, which results in a slightly carbonated wine. There are two styles that can be used:

• Bottling wine without filtering, which lets the wine keep fermenting with the original yeast.
• Malolactic fermentation, used to tone down the acidity of the high acid and low in sugar wine, may be used to produce CO2. This can be found in some Vinho Verde DOC (Portugal).
• Pressure: 2.5-3 atm.
• Dosage/ Liqueur de Tirage: None
• Disgorgement: Depends on the region rules and the producer.

Found in:
Montlouis-sur-Loire Appellation d’Origine Contrôlée (Loire Valley) 

• AOC Website: vinsmontlouissurloire.fr
• Grapes: Chenin Blanc

Prosecco Col Fondo, (labeled “Frizzante”)
Grapes: Glera 85% minimum.
Wine: Typically white and bottled on the lees.

For more on the process of natural method sparkling wines, read:
Gardner, Denise M. “Technical Information about Pét-Nats (Pétillant Naturels, or Sparkling Wines Produced by Méthode Ancestrale).” Penn State Extension Wine & Grapes U., Penn State University, 2 Oct. 2015, psuwineandgrapes.wordpress.com/2015/10/02/technical-information-about-pet-nats-petillant-naturels-or-sparkling-wines-produced-by-methode-ancestrale/. 

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Forced Carbonation

Process: 
In a process similar to carbonating soda, the wine is injected with CO2.

Produces
Force carbonation does not impart any secondary fermentation characteristics to the base wine, however the base wine needs to be of good quality because carbonation may accentuate any wine faults (Jackson, Wine Science).  Forced carbonation does not produce secondary flavors that come from other maturation processes.

Price
The least expensive production methodology. 

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Dossage and Final Production Steps

• Dosage: A touch of sweetness
• Bottle Size
• Final Production Steps

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Dosage - A Touch of Sweetness
Dosage is the addition of “liqueur de dosage” to adjust the taste of the wine after disgorgement to balance out acidity and potentially highlight certain aromas. 

• Poignettage is the process of integrating the dosage liqueur with the wine, the bottle is then shaken vigorously
• Liqueur de dosage: A mixture of sugar and the same wine as the bottle holds. The amount of sugar will vary and is often indicated on the bottle as:

Influence of bottle size

• Half-bottles vs 750ml bottles
  Double the oxygen, therefore they mature more rapidly.
• Magnum vs 750ml bottle:
  There is reduced oxidation in magnum bottles, compared to regular 750ml bottles, as the corks are approximately the same size, therefore the amount of oxygen per ml is approximately half.  

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• Jeroboam vs. Magnum
  Increased UV light exposure in Jeroboam and larger vs. Magnum

​It should be noted that poor-quality glass with rough inner bottle walls can also be a source of greater numbers of nucleation sites and an inducer of gushing (Cordingley, AWRI, 2020).  

Image by: Comité Champagne

​Final Production Steps

• Corking
  The next stage is to fill the bottle back up to 750 milliliters before corking. A wire hood is also placed on the cork to keep it in place.
• Mirage 
  ​The final check on the limpidity of the wine and the last procedure prior to cellaring.

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The Physics and Chemistry of Effervescence and Mousse (Foam)

 The Foam in Sparkling Wine is Described in Two Ways:

• The amount of effervescence (bubbles), which is the amount of dissolved gas in the bottle. 
  • Before opening the bottle, the amount of dissolved CO2 in a bottle is directly correlated to the amount of sugar used in secondary fermentation, as defined in the previous section on Secondary Fermentation.  
  • After opening the bottle, the ability for the gas to escape influences the amount of gas, since the lower the temperature, the more dissolved gas as defined by Henry's (gas) law, which states that the amount of dissolved gas in a liquid is proportional to its partial pressure above the liquid. Sugar [24,25] as well as a higher ABV, diminishes CO2 solubility.
• The ability for the bubbles to turn into a mousse (foam) instead of immediately popping and disappearing. This creates texture, and is referenced in the scientific literature as the Bikerman coefficient [27].

• Cultivar Impact
• Bubble Formation
• Influence of Glass Shape

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Some cultivars of grapes can provide better foam stability than others. Andrés-Lacueva et al., (1997) found that Chardonnay gave Cava the best foam of the grapes tested, and was higher in total and neutral polysaccharides, soluble proteins, total polyphenols, absorbance at 280, 365, and 420 nm, titratable acidity, alcoholic content, conductivity, and malic acid, than the other wines studied.

Bubble Formation in the Glass
Bubble formation, also known as bubble nucleation, forms where there are minute tartrate crystals or on “imperfections” in the glass, which are typically broken ends of cellulose fibers from drying cloths or dust particles. Some sparkling wine glasses even have laser-etched nucleation sites  This occurs because these nucleation sites contain microscopic cavities that can trap air when wine is poured into the glass. The underlying research for this and more on bubble physics can be found in a 2008 literature review by Dr Gerard Liger-Belair of the Georges CHAPPAZ Institute (IGC) at Université de Reims Champagne-Ardenne. This literature review also included the relevant theoretical equations that can be used to calculate CO2 solubilities and the following insight:28 

• The cloud of fog that forms when opening a Champagne bottle is the instantaneous condensation of water vapor due to a theoretical drop in temperature close to 90°C  in the headspace below the champagne surface, which occurs by the sudden gas expansion (pressure change) when the bottle is uncorked. 
• For a less academic version of the work, read this article:  www.americanscientist.org/article/bubbles-and-flow-patterns-in-champagne 

To learn more on sparkling wine physics and Champagne in general, read:
 Dr Liger-Belair’s book, titled Uncorked: The Science of Champagne, which is available in both digital and print editions.

Glass shape influences the aroma of sparkling wine. The exact physics has been studied by Fabien, Liger-Belair, and Polidori in 2019. To summarize the paper:  

Bubbles help to enhance the aroma of the wine by:

• Releasing dissolved gas species and aromas.
•  Agitating the wine as they ascend into the wine, which in turn results in the additional flow of aroma compounds.  

The researchers suspected a close link between both the presence of ascending bubbles and the glass shape, and the release of the numerous VOCs, and the gradual release of CO2 during a tasting.  

The Study
By using four glasses of different shapes (champagne flute, tulip, coupe, ISO tasting glass/white wine glass) in which the time evolution of the liquid (i.e. the wine) and gaseous (i.e.  CO2) phases of the wine in which the following was monitored:

• The gaseous phase which measured the time evolution of the diffusion velocity of 
• Particle image velocimetry (PIV) was used to monitor the dynamic behavior of the liquid phase. 

Found

• An interplay between what is happening within the strongly glass-shape dependent liquid phase and the strongly free surface area gaseous phase above the wine’s surface.
• Champagne flutes (smaller surface area) have a significant wine swirling intensity, which causes CO2 to be released early and are double those tulips at the instant just after the pouring process. This occurs because, in these types of glasses where vorticity is important, the release of dissolved gas by a convection-diffusion mechanism will be increased. 
• Coupes and ISO tasting glasses (larger surface area) have similar gas velocities, which decrease in value very slowly compared to flute and tulip glasses. 
• The velocity at which CO2 molecules in the gas phase return to the atmosphere (in other words, the rate of the sparkling wine bubbles) is closely related to the vorticity and velocity of the liquid medium caused by the aforementioned finding.

As part of service, it should be noted that a cork exits a bottle of Champagne at a typical velocity of 50-60 km/hr (Liger-Belair, 2008), therefore safety is extremely important. 

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Styles of Sparkling Wine

Traditional Method Sparkling Wines

Champagne Research Institute
​The Georges CHAPPAZ Institute (IGC) at Université de Reims Champagne-Ardenne
www.univ-reims.fr/igc-en/about-us/about-us,18291,31675.html 

Charmat Method Sparkling Wine

New World Sparkling Wine Regions

Production Method
Most new world regions have required production methodologies for sparkling wine.  This means they can range from Traditional Method to Forced Carbonation wines.

Grapes
Many of the New World Sparkling Wine Regions are based upon Chardonnay and Pinot Noir.

Regions
The New World sparkling wine regions mirror the cool weather (Winkler Ib and Winkler II) Chardonnay growing regions of the world.  

Australia: 

• Tasmania
• Victoria: Yarra Valley, Mornington Peninsula
• South Australia: Adelaide Hills (nicknamed Sparkling Hills)

New Zealand:

• Marlborough
• Hawke's Bay

California: 

• Sonoma Coast AVA:  
• Carneros AVA, Russian River AVA, 
• Central Coast AVA:
• Mendocino AVA, Anderson Valley AVA, Santa Maria Valley AVA, Santa Ynez Valley AVA, Monterey AVA (Santa Lucia Highlands AVA, Arroyo Seco AVA)

Look for more insight in the upcoming Chardonnay issue of Hawaii Beverage Guide.

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Resources and Suggested Reading 

1. Little Ice Age. (n.d.). Retrieved November 19, 2021, from www.britannica.com/science/Little-Ice-Age

2. Le Comité Interprofessionnel du vin de Champagne. (n.d.). Effervescence. Retrieved November 19, 2021, from www.champagne.fr/en/from-vine-to-wine/what-is-champagne-wine/effervescence

3. Gardner, D. M. (2015, September 18). The bubbles: Basics about sparkling wine production techniques. Retrieved November 16, 2021, from psuwineandgrapes.wordpress.com/2015/09/18/the-bubbles-basics-about-sparkling-wine-or-sparkling-cider-production-techniques/

4. Liu, P.-H., Vrigneau, C., Salmon, T., Hoang, D. A., Boulet, J.-C., Jégou, S., & Marchal, R. (2018). Influence of Grape Berry Maturity on Juice and Base Wine Composition and Foaming Properties of Sparkling Wines from the Champagne Region. Molecules, 23(6), 1372. doi:10.3390/molecules23061372

5. Kupfer VM, Vogt EI, Ziegler T, Vogel RF, Niessen L. Comparative protein profile analysis of wines made from Botrytis cinerea infected and healthy grapes reveals a novel biomarker for gushing in sparkling wine. Food Res Int. 2017 Sep;99(Pt 1):501-509. doi:10.1016/j.foodres.2017.06.004. Epub 2017 Jun 3. PMID: 28784511. 

6. Australian Wine Research Institute. (2020, November). Sparkling wine gushing: Not a cause for celebration. Retrieved November 19, 2021, from www.awri.com.au/wp-content/uploads/2021/01/s2195.pdf

7. Marchal, Richard & Kemp, Belinda & Ménissier, & Oluwa, & Pannetier, & Whitehead, Claire & Whitehead, Danielle & Foss, Chris. (2012). Press fraction composition of sparkling must and base wine.   www.researchgate.net/publication/261507528_Press_fraction_composition_of_sparkling_must_and_base_wine

8. Dambrouck, T., Marchal, R., Cilindre, C., Parmentier, M., & Jeandet, P. (2007). Determination (Using Immunoquantification) of the Grape Invertase Content upon Fining vs Changes in the Total Protein Content of Wine. Relationships with Wine Foaming Properties. Macromolecules and Secondary Metabolites of Grapevine and Wines, pp 205-211. Source: www.researchgate.net/publication/282811942_Determination_Using_Immunoquantification_of_the_Grape_Invertase_Content_upon_Fining_vs_Changes_in_the_Total_Protein_Content_of_Wine_Relationships_with_Wine_Foaming_Properties 

9. Jeandet, Philippe. (2011). Sparkling Wine Production.  www.researchgate.net/publication/278303662_Sparkling_Wine_Production

10. Gardner, D. M. (2015)

11. Australian Wine Research Institute. (2020, September). Malolactic fermentation in white and sparkling wines. Retrieved November 19, 2021, from www.awri.com.au/wp-content/uploads/2018/03/MLF-in-white-and-sparkling-wine.pdf

12. Guilloux-Benatier, M. (2006), Yeast autolysis in sparkling wine – a review. Australian Journal of Grape and Wine Research, 12: 119-127. https://doi.org/10.1111/j.1755-0238.2006.tb00051.x
Source: www.scribd.com/document/78997658/Yeast-Autolysis-in-Sparkling-Wine-A-Review-SUB

13. Bottling and secondary fermentation. (n.d.). Retrieved November 16, 2021, from www.champagne.fr/en/from-vine-to-wine/wine-making/bottling-and-secondary-fermentation 

14. Massoutier, Catherine & Alexandre, Hervé & Feuillat, Michel & Charpentier, Claudine. (1998). Isolation and characterization of cryotolerant Saccharomyces strains. Vitis -Geilweilerhof-. 37. 55-59. 
https://www.researchgate.net/publication/256766647_Isolation_and_characterization_of_cryotolerant_Saccharomyces_strains |

15. Babayan, T. L., Bezrukov, M. G., Latov, V. K., Belikov, V. M., Belavtseva, E. M., & Titova, E. F. (1981). Induced autolysis of Saccharomyces cerevisiae: morphological effects, rheological effects, and dynamics of accumulation of extracellular hydrolysis products. Current microbiology, 5(3), 163-168.

16. Piton, F., Charpentier, M., & Troton, D. (1988). Cell wall and lipid changes in Saccharomyces cerevisiae during aging of champagne wine. American journal of enology and viticulture, 39(3), 221-226. https://www.ajevonline.org/content/39/3/221.short 

17. Andrés-Lacueva, C., Lamuela-Raventós, R. M., Buxaderas, S., & de la Torre-Boronat, M. D. C. (1997). Influence of variety and aging on foaming properties of cava (sparkling wine). 2. Journal of Agricultural and Food Chemistry, 45(7), 2520-2525.

18. Tominaga T, Guimbertau G, Dubourdieu D. Role of certain volatile thiols in the bouquet of aged champagne wines. J Agric Food Chem. 2003 Feb 12;51(4):1016-20. doi: 10.1021/jf020755k. PMID: 12568565.

19. Francioli, S., Torrens, J., Riu-Aumatell, M., López-Tamames, E., & Buxaderas, S. (2003). Volatile compounds by SPME-GC as age markers of sparkling wines. American Journal of Enology and Viticulture, 54(3), 158-162. 

20. Australian Wine Research Institute. (2020, November). Sparkling wine gushing: Not a cause for celebration. Retrieved November 19, 2021, from www.awri.com.au/wp-content/uploads/2021/01/s2195.pdf 

21. Alcohol and Tobacco Tax and Trade Bureau. (2018, August 10). TTB: Wine: Beverage alcohol manual. Retrieved November 19, 2021, from www.ttb.gov/wine/beverage-alcohol-manual

22. Gardner, Denise M. “Technical Information about Pét-Nats (Pétillant Naturels, or Sparkling Wines Produced by Méthode Ancestrale).” Penn State Extension Wine & Grapes U., Penn State University, 2 Oct. 2015, www.psuwineandgrapes.wordpress.com/2015/10/02/technical-information-about-pet-nats-petillant-naturels-or-sparkling-wines-produced-by-methode-ancestrale/. 

23. Champagne.fr

24. Descoins, Charles & Mathlouthi, Mohamed & Moual, Michel & Hennequin, James. (2006). Carbonation monitoring of beverages in a laboratory scale unit with on-line measurement of dissolved CO2. Food Chemistry. 95. 541-553. 10.1016/j.foodchem.2004.11.031.  www.researchgate.net/publication/222688104_Carbonation_monitoring_of_beverage_in_a_laboratory_scale_unit_with_on-line_measurement_of_dissolved_CO2 

25. Lonvaud-Funel, A., & Matsumoto, N. (1979). Le coefficient de solubilité du gaz carbonique dans les vins. Vitis, 18, 137-147. https://doi.org/10.5073/vitis.1979.18.137-147.

26. Zoecklein, B. (n.d.). WINERY GASES: CARBON DIOXIDE, ARGON, AND NITROGEN. Wine/Enology Grape Chemistry Groupe at Va Tech Retrieved November 19, 2021, from
www.apps.fst.vt.edu/extension/enology/downloads/wm_issues/Winery%20Gases/Winery%20Gases1.pdf

27. Bikerman, J. J. (1973). Measurement of foaminess. In Foams (pp. 65-97). Springer, Berlin, Heidelberg.

28. Liger-Belair, Gérard & Polidori, Guillaume & Jeandet, Philippe. (2008). Recent advances in the science of Champagne bubbles. Chemical Society reviews. 37. 2490-511. 10.1039/b717798b. www.researchgate.net/publication/23412886_Recent_advances_in_the_science_of_Champagne_bubbles

29. Fabien, Beaumont & Liger-Belair, Gérard & Polidori, Guillaume. (2019). Unsteady evolution of the two-phase flow in sparkling wine tasting and the subsequent role of glass shape. Experiments in Fluids. 60. 10.1007/s00348-019-2759-5. www.researchgate.net/publication/333786197_Unsteady_evolution_of_the_two-phase_flow_in_sparkling_wine_tasting_and_the_subsequent_role_of_glass_shape