The Bubbles: Basics about Sparkling Wine Production Techniques
By: Denise M. Gardner
There are several styles of sparkling wine that a winery should consider prior to making plans to incorporate a sparkling product into their wine portfolio. To obtain a quality product, varietal selection and winery resources (i.e., funds, equipment, personnel, time availability) should be considered before undergoing production.
A variety of these production methods can also be applied in cideries when producing various hard cider products. Although the specifications for apple selection would vary, production of the product would be quite similar.
Viticulture and Variety Selection for Sparkling Wine
While an older resource, Ough’s “Winemaking Basics” (1992) book outlines the basic requirements in grapes destined for sparkling wine production. Grapes should be picked at 8.0 g/L tartaric acid (or higher) and at 18 – 21°Brix, with a final alcoholic concentration goal of up to 11.0% if the wine was to be fermented dry (Ough 1992).
Jones et al. (2014) details these harvesting details further indicating that a low pH, high titratable acidity (TA), and “lower” sugar concentration is ideal for sparkling wine production. Typical harvest parameters in Champagne, the world’s leading sparkling wine producing-region, include: an estimated final alcohol (v/v) of 9% based on starting sugar concentration, 12.0 g/L tartaric acid, and a pH of 2.9, but parameters vary and are determined annually, dependent on the growing season (Jones et al. 2014). Unlike many New World winegrowing regions, Champagne and Cava have viticultural regulations dictating grape growing practices and harvest parameters (Jones et al. 2014). Other sparkling wine producing regions may mimic these parameters in terms of optimizing quality in their sparkling wine products. Both Zoecklein (2002) and Jones et al. (2014) have detailed harvest parameters for grapes destined for sparkling wine production, although optimal ranges can vary from region-to-region and variety-to-variety: 16.0 – 20.0°Brix, 10.0 – 16.0 g/L tartaric acid, and a pH of 2.90 – 3.20.
Traditional varieties used for Champagne production include Chardonnay, Pinot Noir, and Pinot Meunier; each variety may be made into a varietal Champagne or blended to produce a particular house style. For Cava, a Spanish sparkling wine made using the traditional method (see below), the primary varieties used for production are: Macabea (Viura), Parellada, and Xarel.lo (Jones et al. 2014).
When a “white” or “rosé” hued sparkling wine is desired, red [grape] varieties should be pressed quickly, with minimal skin contact (Ough 1992), and although full-cluster pressing is often preferred, if the grapes are in good condition, crushing followed by pressing should be utilized for efficiency (Ough 1992, Zoecklein 2002). The “pink” color may also be added in the final stages of production by adding a small concentration of red still wine in the dosage.
However, the evaluation of alternative varieties has been studied (Martínez-Lapuente et al. 2013) and utilized in industry. Germany, for example, produces several sparkling wines using varieties such as Riesling, Silvaner, Pinot Blanc, and Pinot Gris. Italian sparkling wines range from Muscat (Moscato) to Lambrusco and Acqui (Brachetto d’Acqui), with the latter two varieties being of a deep red color. Red-hued sparkling Shiraz wines are also popular in Australia. While the opportunities and variability of sparkling wine is endless, each variety presents its own sets of challenges in terms of production and quality.
Methods of Production
Méthode Champenoise (Traditional Method, Méthode Traditionelle)
The traditional method of making sparkling wine includes growing grapes specifically for sparkling wine production, which are picked on the parameters discussed above. Once the grapes are crushed and/or pressed, the juice undergoes primary fermentation in bulk. The resulting base wine is blended (cuvée) to meet a particular house-style, and after stabilization, it is bottled with a sugar and yeast addition (tirage, liqueur de tirage) in which a second fermentation takes place in the bottle to produce carbon dioxide. The carbon dioxide, and resulting pressure, is conserved in the bottle. Following the completion of the second fermentation, the bottles are riddled to collect yeast lees into a concentrated pellet within the neck of the bottle. The riddling period also allows the wine contact with the lees and autolytic products. Today, riddling can take place manually (by hand) or by use of machine-automatic riddling racks. After a specific period of time allocation for riddling, the wine is disgorged to remove the precipitated lees contents from the bottle. The bottle is quickly filled with a final sugar addition (dosage, liqueur d’expédition) and sealed with a Champagne cork. The sugar addition in the dosage will determine the sparkling wine’s final sweetness level. Wine examples made using the traditional method include Champagne and Cava.
There are a variety of resources available for producing sparkling wines using the traditional method. One of the easiest to access online is Dr. Bruce Zoecklein’s 2002 edition of “A Review of Méthode Champenoise Production.” Zoecklein’s review is very thorough, and the reader will quickly capture terminology and production situations associated with sparkling wine production utilizing any of the methods discussed in this post.
Additionally, Brock University has taken an interest in sparkling wine production due to the recent interest in the product throughout Canada’s wine industry (http://www.brocku.ca/ccovi/outreach-services/ontario-sparkling-wine-technic). You can access many of the presentations that were previously available through Brock’s “Sparkling Wine Technical Symposium:”
- “Disgorging, gushing, and foaming” by Dr. Bertrand Robillard
- “Sparkling Wine Production of Tasmania including phenolic and MLF management” by Ed Carr
- “Making wines for specific markets and challenges associated with alternative varieties” by Larry Mawby
- “Sparkling wine closures and consumer perceptions” by Jamie Goode
Charmat Process (Tank Method, Bulk Method)
This process is considered less labor intensive than the traditional method, as it does not involve a second alcoholic fermentation in individual bottles and disgorgement. Some may consider the Charmat process an “inferior” way to make sparkling wine. However, the Charmat process is traditionally used in sparkling wine production of aromatic varieties (e.g., Chenin Blanc, Riesling, Muscat, Gewurztraminer, etc.) to avoid heavy contact with yeast lees that are otherwise available through méthode Champenoise processing. Extended lees contact could easily mask the natural fruity aromas and flavors produced by the grape. Commercially, this method could be applied to a number of grape varieties and it is used to produce several quality sparkling wine styles.
In the Charmat method, after the base wine cuvée is established, it is transferred into a cold, pressurized tank instead of a bottle. Yeast and sugar are added to the tank to undergo a second alcoholic fermentation under pressure, which ensures the retention of carbon dioxide. As the surface area of yeast-to-wine is a lot less than in the traditional method, the autolytic yeast character is not as prevalent in these wines. Once the second fermentation is complete, the wine is filtered and transferred to a second cold, pressurized tank that contains the dosage for the entire batch of wine. Wine is bottled from the tank. Examples of commercial wines that utilize the Charmat method include Prosecco (Italy) and Sekt (Germany).
The transfer method utilizes techniques from both traditional and Charmat methods. Initially, production follows all of the steps in the traditional method through completion of the second alcoholic fermentation. Therefore, the second alcoholic fermentation takes place in individual bottles.
At the completion of the second alcoholic fermentation, the bottles are emptied into a pressurized tank, filtered, and moved to a second pressurized tank that contains the dosage. Wines are then bottled, and may be labeled as “Fermented in the Bottle” or “Bottle Fermented,” although this implies that the wine was not fermented in the specific bottle it is being sold in, as in the case of the traditional method.
Partial Fermentation (Moscato)
This is an alteration from the Charmat method, and does not allow for a full fermentation of the base wine. This allows for a sweeter, carbonated wine to be made without fully completing the first alcoholic fermentation in either fermentation step.
In the first fermentation, the wine is only fermented up to about 6% alcohol, rapidly chilled, racked and kept cool. Once the wine is transferred, the base wine will be warmed up in a pressurized tank to allow for more alcohol production, but with retention of residual sugar. Once completed, the wine is sterile filtered and bottled. Examples of commercial wines that utilize the partial fermentation method include Moscato d’Asti and Brachetto d’Acqui (Brachetto) from Italy, although many commercial wines around the world utilize parts of this process to retain residual sugar and light carbonation in the final product.
Regardless of what type of sparkling wine you may end up making, there are also a variety of resources available through commercial suppliers.
- Scott Labs: Scott Labs has assisted several sparkling wine producers in producing quality sparkling wine for several years. A series of products through the various stages of sparkling wine production are listed on their website: http://www.scottlab.com/products-122.aspx
- Laffort: Laffort has its own line of sparkling wine products and a hand-held disgorging key: http://www.laffort.com/en/products/sparkling-wines. Laffort has recently been working with the west coast custom crush facility, Rack and Riddle to improve sparkling wine education and awareness.
- Enartis Vinquiry: Enartis Vinquiry provides a 2-page tech sheet pertaining to products available for Charmat sparkling wine production, which can be found here: http://www.enartisvinquiry.com/download/tech_info/Perle%20Range.pdf. Additional information pertaining to starting a yeast culture (pied du cuve) can be found here: http://www.enartisvinquiry.com/download/tech_info/24%20Hour%20Pied%20de%20Cuve.pdf
Jones, J.E., F.L. Kerslake, D.C. Close, and R.G. Dambergs. 2014. Viticulture for Sparkling Wine Production: A Review. Am. J. Enol. Vitic. 65(4):407-416.
Martínez-Lapuente, L., Z. Guadalupe, B. Ayestarán, M. Ortega-Heras, and S. Pérez-Magariño. 2013. Sparkling Wines Produced from Alternative Varieties: Sensory Attributes and Evolution of Phenolics during Winemaking and Aging. Am. J. Enol. Vitic. 64(1):39-49.
Ough, C.S. 1992. Winemaking Basics.
Zocklein, B.W. 2002. A Review of Méthode Champenoise Production.