Standard Options in Sparkling Winemaking Flashcards
Explain the growing environment?
Cool climates where grapes struggle to ripen are ideal for sparkling wines. The grapes are just-ripe in flavour, but retain the acidity required for high-quality sparkling wines. Sugar accumulates slowly, giving still, base wines with low alcohol (around 9–11% abv). This is necessary because the second fermentation used in many methods of making sparkling wines produces an additional 1–2% abv.
Grapes for sparkling wine therefore tend to be grown in regions that are at greater latitudes, such as Champagne, England or Tasmania, or that have local cooling influences, such as those near to the coast (Sonoma) or at high altitude (Trentodoc). In warmer areas, the grapes tend to have riper fruit flavours and lower acidity compared to grapes grown in cooler sites. This may be desirable for short-aged wines (e.g. those made by tank method or with short time on the lees in transfer or traditional method), as the fruit will provide the only or dominant flavours. However, to make elegant, balanced, long-lees-aged sparkling wines less intense fruit flavours are usually preferable.
Less expensive sparkling wines may be grown in areas where land is cheaper and easier to cultivate, for example on flat, fertile plains. In some cases, grapes for sparkling wines are grown in places that are simply less suitable or unsuitable for still wines (grapes would not achieve the concentration and/or ripeness needed for good-quality still wines).
What grape varieties are used to make premium and super premium sparkling wines?
CHARDONNAY
This variety is well suited to the production of autolytic styles of sparkling wines. Its subtle apple and citrus aromas and flavours compliment rather than compete with the biscuit or pastry aromas from yeast autolysis (the breaking down of dead cells, see Lees Ageing). Its early ripening of flavours is an asset in cool conditions and it also retains the high levels of acidity and low levels of alcohol needed in sparkling wines while avoiding under-ripe flavours.
Thus, it brings apple and citrus flavours and high acidity to the blend. However, being early budding, it is vulnerable to spring frosts. It is also prone to coulure and millerandage. It has more disease resistance than Pinot Noir, but is susceptible to powdery mildew, grapevine yellows and to botrytis bunch rot in wet periods before harvest. Yields can be high in the best years without loss of quality, making this an attractive option for growers.
PINOT NOIR
This variety is also an early budding and early ripening variety and is therefore suited to a cool climate. Being early budding also makes it prone to spring frosts. It is prone to coulure. The yields are more moderate than Chardonnay and the quality drops if the yield level is too high. It is thin skinned and more disease prone (downy mildew especially, powdery mildew, botrytis bunch rot, fan leaf and leaf roll). It lends body to the blend.
Chardonnay and Pinot Noir are used to produce sparkling wines in wine regions across the world. However, other sparkling wines are made from grape varieties that are local to their region, for example Macabeo, Xarel-lo and Parellada in Cava, or Glera in Prosecco. Factors within the grape variety that can influence the style of the wine are:
- intensity of aromas (aromatic or neutral grape variety)
- ability to retain acidity while ripening
- how the base wine responds to autolysis where applicable, for example, Chardonnay becomes creamy, whereas Xarel-lo becomes toasty and smoky.
Explain vineyard management with sparkling wine?
Grapes for sparkling wines are often grown at higher yields than for still wines. High acid levels, low potential alcohol levels and delicate flavours are desirable in most sparkling wines, and these characteristics are better achieved by high yields. Therefore, the output from
the vineyard land can be maximised. In cool, relatively rainy climates, such as Champagne, this can provide some assurance that even if some damaged fruit has to be removed, a reasonable sized crop can still be harvested.
A range of training and trellising techniques may be used depending on the region, its climate, the varieties grown and the nutritional status of the soils. However, a priority in all areas will be to obtain clean, healthy fruit. The perception of any off flavours from diseased fruit can be enhanced by the effects of effervescence in the wine. In addition, the enzyme laccase released by botrytis-infected grapes can cause serious oxidation.
Explain harvesting for sparkling wine?
Harvesting occurs earlier than for still wine production in order to achieve the high acid, low alcohol profile desired for sparkling wine. Early picking also means that the grapes are less likely still to be on the vine as rainy autumn weather starts, reducing risk of fungal disease. Although low potential alcohol and high acidity is desirable, unripe flavours are not, and are thought to become more prominent as the wine matures.
Hand harvesting and machine harvesting are both used for sparkling wine production, depending on location and local wine laws. Hand harvesting permits sorting at picking and post-harvest selection to exclude disease-infected grapes. Hand picking and collecting in small crates minimise the splitting and crushing of the grapes, as well as the subsequent oxidation of this juice along with extraction of phenolics (including colour and tannin). However, hand harvesting is slow, labour-intensive and can be expensive. Machine harvesting can rupture the skin of the grapes, resulting in phenolic extraction and oxidation. The advantages of machine harvesting are that it is faster, so for large estates the grapes are more likely to all be picked at the desired point of ripeness, and it is cheaper. Diseases or damaged grapes can be removed by hand just prior to machine harvest, allowing a degree of selection, however, this does increase costs. It also permits night-time harvesting, thus delivering cooler grapes. This is an advantage because oxidation is slowed down, resulting in fresher wines.
Explain the pressing process during sparkling winemaking?
Whole-bunch pressing is often practised for premium traditional method sparkling wines. This is one of the gentlest forms of pressing, providing a delicate juice that is low in solids and phenolics (including tannins and the anthocyanins that provide colour). The stems also help to create a network of channels through which the juice can flow easily, minimising the pressure required. However, fewer bunches can be loaded into the press at any one time compared to crushed grapes, and therefore this process is more time consuming.
Pressing should be performed as quickly and gently as possible, especially for the black skinned grape varieties, minimising maceration with and extraction from the skins, which would bring unwanted colour and tannins. These phenolic compounds can make the wine taste bitter and feel coarse on the palate. Both pneumatic and basket presses are commonly used, due to their ability to press very gently. It is common to split the juice into different press fractions, and in some regions the maximum amount of press juice (as opposed to free run juice) that can be used is controlled. The different press fractions can make useful blending options. The juice from press fractions is higher in phenolics, solids and pH than the free run juice. Wines made from press juice tend to be faster maturing, and therefore this fraction can be useful in wines with a short maturation that are made for immediate consumption.
The juice is clarified before fermentation and the winemaker can choose any of the options available for clarification when making still white wines. If there is excessive tannin or colour at this stage, fining (e.g. with casein, gelatine or PVPP [polyvinylpolypyrrolidone]) may be used to amend the juice.
Explain primary fermentation in sparkling winemaking?
Fermentation temperatures of 14–20°C (57–68°F) are typical for the primary fermentation to retain fruit flavours but ensure the temperatures are not too cold for the yeast. The low pH of the juice makes the environment quite stressful for yeast. Most primary fermentation takes place in stainless steel tanks to allow large volumes to be fermented with temperature control and for ease of cleaning the tanks before and after fermentation.
A reliable healthy ferment is a priority in sparkling winemaking. Cultured yeasts that are able to ferment reliably to dryness in high acid and low pH conditions are typically used. Some strains of yeast can promote certain flavours in the wines, for example thiols or esters. This may be positive in tank method sparkling wines that are based on fruity flavours. However, pronounced primary flavours are generally not wanted in autolytic styles of wine as they may compete with the flavours from autolysis. Therefore, these wines will be made using a neutral yeast that does not enhance these flavours.
It is common to use the same yeast for both the first and second fermentation; therefore, the stressful environmental conditions of the second fermentation need to be considered when choosing a yeast strain. During second fermentation, the yeast must be able to start fermenting in alcoholic conditions (10% abv is too high for many yeasts) with low pH, and continue fermenting through low temperatures, in high pressure and with poor availability of nutrients. Rapid autolysis and easy flocculation (the process by which fine particles clump together) are desirable in traditional method wines. ‘Prise de mousse’ (EC1118) is one of the most common cultured yeasts used in sparkling wine production.
Malolactic conversion may be used to reduce acidity in an excessively acidic wine. It can also be used to enhance texture. The lactic acid that is produced in malolactic conversion is perceived to be creamier in texture than other acids, such as tartaric. (The buttery flavours found on white wines that have undergone malolactic conversion are not typically found on sparkling wines. This is because diacetyl, which gives the buttery flavour, is metabolised by the yeast during the second fermentation.) If malolactic conversion does not take place at this stage, there is the risk that it could take place during the second fermentation. This is problematic for traditional method wines as it can turn the wine hazy, which would be difficult to rectify in the bottle. Therefore, if malolactic conversion is not desired, the wine may be sterile filtered.
Explain the handling of the base wine?
There are many options open to the winemaker for refining and modifying the base wine before it undergoes second fermentation. Some winemakers choose to mature the base wine in oak and/or leave the wine on its lees. The aromas and flavours of oak (vanilla, toast and spice) are usually magnified in the sparkling wine and therefore, where new oak is used, it will only be a very small proportion of a blend. Most often, seasoned barrels will be used. If the producer is creating a fruity style of wine (e.g. Prosecco or Asti), oak will not be used.
Explain Assemblage (blending)?
ASSEMBLAGE (BLENDING)
The blending of wines, from different vineyard sites, grape varieties, vintages and wines that have undergone different winemaking techniques is one of the hallmarks of sparkling wine production. Similar to the production of still wines, the purpose of blending is for:
balance – for example, Pinot Noir can lend more body to a blend, whereas blending in Chardonnay can give higher acidity; the same effect could come from using warmer and cooler vineyard sites with the same single grape variety
- consistency – for example, many sparkling wine producers make a non-vintage blend and, for this style of wine, consistency of the product from one year to the next is very important
- style – for example, a producer may choose to make their least expensive wine in an early-drinking style, and therefore want to create an approachable style with more ripe fruit and less acidity; their top wine may be styled to be suited to longer ageing, both on and off the lees, and therefore have more concentrated flavours and higher acidity
- rosé wines – some rosé sparkling wines are made by blending red and white base wines and thus blending defines this style of wine
- complexity – a greater range of flavours may be captured by blending different grapes varieties, vineyard sites and vintages, or blending base wines that have undergone different treatment (e.g. oak maturation); for instance, older wines can add more dried fruit characters to the fresh fruit of the current year
- minimisation of faults – if a batch of wine has a minor fault, it can be rescued and sold if it is blended with a larger volume of a sound wine
- volume – in areas with small vineyard holdings, winemakers are likely to blend the wines from different vineyards to produce viable volumes of certain wines; blending grape varieties or reserve wines can also help to increase volumes
- price – for example, inexpensive and mid-priced wines in particular may need to be made to a certain price point. Blending in cheaper grape varieties, for example Meunier (previously known as Pinot Meunier), alongside the more prestigious varieties of Chardonnay and Pinot Noir may enable a producer to keep prices affordable, while still benefiting from the well-known names of the prestigious varieties. Cheaper wines may also make more use of press wines, as opposed to free run juice.
For traditional method wines, the final blend should be stabilised for tartrates and proteins before being bottled for second fermentation. For all methods of production for sparkling wine, base wines should be clarified before second fermentation. Again, any of the methods used in still wine production can be used for sparkling wine.
Explain traditional method in sparkling wine making?
a.k.a. Méthode Champenoise, méthode traditionnelle, Methode Cap Classique, Metodo Classico, klassische flaschengärung
Examples: Cava, Champagne, Crémant, some Sekt, Italian Metodo Classico wines (including Franciacorta and Trento)
Bottle Pressure: 5–7 atmospheres or ~75–99 psi
The traditional method of sparkling winemaking was awarded a UNESCO heritage in Champagne in 2015. It is–arguably–the most appreciated method for sparkling wine production in terms of quality, and at the same time it is also the most costly in terms of production. The most important facet of the traditional method is that the transformation from a still to a sparkling wine occurs entirely inside the bottle.
- Base Wine or “Cuvée”: grapes are picked (usually just a tinsy bit younger to preserve acidity) and fermented into a dry wine. The winemaker then takes the various base wines and blends them together into what the French call a “cuvée”, which is the final sparkling wine blend.
- Tirage: Yeast and sugars are added to the cuvée to start the second fermentation and wines are bottled (and topped with crown caps).
- 2nd Fermentation: (inside the bottle) The second fermentation adds about 1.3% more alcohol and the process creates CO2 which is trapped inside the bottle thus carbonating the wine. The yeast dies in a process called autolysis and remain in the bottle.
- Aging: Wines are aged on their lees (the autolytic yeast particles) for a period of time to develop texture in the wine. Champagne requires a minimum of 15 months of aging (36 mos for vintage Champage). Cava requires a minimum of 9 months of aging but requires up to 30 months for Gran Reserva Cava. Most believe the longer the wine ages on its lees, the better.
- Riddling: Clarification occurs by settling the bottle upside down and the dead yeast cells collect in the neck of the bottle.
- Disgorging: Removing sediment from bottle. The bottles are placed upside down into freezing liquid which causes the yeast bits to freeze in the neck of the bottle. The crown cap is then popped off momentarily which allows the frozen chunk of lees to shoot out of the pressurized bottle.
- Dosage: A mixture of wine and sugar (called Exposition liqueur) is added to fill bottles and then bottles are corked, wired and labeled.
Explain Second fermentation in traditional method of sparkling wine?
In the Traditional Method, second fermentation occurs in the same bottle in which the wine is later sold. A liqueur de tirage is added to the base wine to achieve a second fermentation. This is a mixture of wine and/or must, sugar, cultured yeasts, yeast nutrients and a clarifying agent such as bentonite and/or alginate (seaweed extract to facilitate riddling). The amount of sugar used depends on the degree of effervescence required. In most fully sparkling wines, 24 g of sucrose per litre is added. During fermentation, the yeast converts the sugar to alcohol (about +1.5% for an addition of 24 g/L of sucrose) and CO2. Unable to escape from the bottle, the CO2 produces a pressure considered appropriate for most sparkling wines, namely six atmospheres (also referred to as ‘bar’). Less sugar will be added if the winemaker wants to create a sparkling wine with lower pressure. The sugar added at this stage does not affect the final sweetness of the wine as the yeast ferment the wine to dryness.
The second fermentation is often called the prise de mousse, which literally means ‘capturing the sparkle’. This fermentation requires inoculation of the wine with a cultured yeast that is able to ferment in unfavourable conditions. The strains that are commercially available have slightly different properties, but all with the aptitude for commencing fermentation in wine with 9.5–11% abv, a moderate temperature of around 16 ̊C (61 ̊F) and pH values often below 3, and later withstanding high pressure as it completes fermentation in the bottle. Yeast cells must also flocculate readily to produce a coarse sediment that can be efficiently removed by riddling.
After addition of the liqueur de tirage and inoculation, the wine is bottled and sealed with a crown cap that holds in place a small plastic pot in the bottle to catch the sediment. The bottles are stored horizontally ‘sur latte’ at a constant temperature of approximately 10–12 ̊C. The length of the fermentation depends primarily on the temperature. A cooler temperature results in a slower fermentation, and some claim that this produces a more complex finished wine. In many cases, the fermentation lasts 4–6 weeks. A stable temperature is also important to maintain yeast viability under difficult fermentation conditions.
Explain lees aging in traditional method of sparkling wine?
After fermentation, the producer will normally choose to age the wines before removing the yeast. The bottles can be stored horizontally in stacks or in metal cages, at temperatures of around 10 ̊C. The length of time for yeast contact during maturation varies. The duration of lees ageing can be a minimum of nine months; for example, for Cava. More typical is 15–18 months, at which point the effects of autolysis become detectable. The length of time depends on the style sought (fresh fruit character v. lees-aged character), the price that can be attained for the wine at the end of the process and the financial ability to invest in longer periods of lees ageing.
The benefits of this lees ageing are derived from autolysis, the enzymatic breakdown of dead yeast cells. Autolysis usually continues for four to five years but has been known to last for ten years. It is best known for producing compounds that add a biscuit complexity. Some sparkling wines are kept on the lees after autolysis has finished. The anti-oxidative qualities of yeast cells protect the wine from oxidation, in comparison to a disgorged wine of the same age. However, the longer a wine is kept in this state, the faster its evolution once disgorged. This is because the older a sparkling wine becomes, the less it can withstand
the sudden shock of oxygen at disgorgement. In Champagne an example is Bollinger ‘R.D.’ (‘recently disgorged’), which is intended to be drunk soon after release.
Explain riddling and disgorgement in traditional method of sparkling wine?
After ageing sur latte, the wines are either placed into pupitres for hand riddling or moved to computer-controlled gyropalettes for riddling (remuage).
The basic effect is the same for both mechanisms. The process of gradually twisting or rotating the bottles while bringing them from the horizontal to the vertical position (cap down) allows the lees to flocculate and slowly move towards the neck of the bottle. Manual riddling takes up to eight weeks to complete, while riddling using gyropalettes takes three to four days.
If wines have to be stored before they are disgorged, they are stored upside down on their necks (sur pointe) so that the lees remain in the neck of the bottle.
With the yeast collected above the closure, the yeast must now be removed with minimal loss of wine and pressure. This process used to occur by hand, and sometimes still does, however, for the main part, disgorgement has become an automated process. The bottles are cooled to approximately 7 ̊C (45 ̊F) and the necks are immersed in a bath of frozen brine. This quickly freezes the yeast sediment in the neck, easing its extraction and ensuring the sediment does not fall back into the wine when the bottle is turned upright. Cooling also increases the solubility of carbon dioxide and so reduces the likelihood of the wine gushing upon opening. The disgorging machine inverts the bottle (so that it is now upright), removes the crown cap and allows the pressure within the bottle to eject the frozen yeast plug. Liqueur d’expédition is added before the bottle is fitted with a cork, wire muzzle and metal capsule.
The liqueur d’expédition is a mixture of wine and sugar (the sugar is referred to as the dosage) or RCGM (rectified concentrated grape must). It tops up the bottle where some wine may have escaped during disgorgement and determines the sweetness of the final wine. There has been a growing trend, albeit from a small base, of Brut Nature (no dosage) and especially Extra Brut (a dosage that results in a wine with less than 6 g/L final sugar).
The role of the dosage is to balance the acidity, which is especially important in young wines. The perception of acidity rounds out with age, thus the older the wine at disgorgement, the smaller the dosage required. However, at least some sugar is usually desired to encourage the development of classic post-disgorgement aromas. The sugar in the liqueur d’expédition reacts with compounds formed during yeast autolysis in a process called the Maillard reaction. This encourages the development of roasted, toasted vanilla aromas, and the cork-sealed sparkling wines may be stored for an extra few months to allow the development of these aromas before release onto the market.
Most sparkling wine is labelled with the EU’s labelling terms for sweetness in sparkling wines.
Explain the Transfer Method?
The transfer method was developed in the 1940s to avoid the cost of manual riddling while retaining the bready, biscuit notes attained through yeast autolysis in bottle. It also has the benefit of reducing bottle-to-bottle variation given that the wine from individual bottles is blended together in a tank before final bottling. This also means it is generally easier to make final adjustments to the wine. With advancements in automated riddling, many of the key advantages of the Transfer Method have become less significant. However, it can still deliver some cost and time savings for high-volume producers by removing the need for riddling. Transfer method is used in Champagne (and other regions) to fill bottles smaller than 37.5 cL and larger than 300 cL, as these sizes are difficult to riddle.
The production of the wine up to riddling is essentially the same as the Traditional Method, with second fermentation taking place in bottles. However, because riddling does not take place, fining agents to aid flocculation do not need to be added within the liqueur de tirage. After lees ageing in bottle, the wine is chilled to 0 ̊C before discharge. The bottles are opened by a transfer machine and the wine is poured into pressurized receiving tanks. The wine is usually sweetened, SO2 is added, and sterile filtering is carried out just prior to bottling. The back labels of such wines may state ‘Fermented in bottle’ rather than ‘Fermented in this bottle’.
Explain the Ancestral Method?
In this method partly fermented must is put into bottles and the remaining sugar is converted into alcohol and CO2, providing the effervescence. Sugar levels in the partly fermented must can be measured accurately and therefore the final level of pressure can be estimated. The phase of fermentation in the bottle will throw a deposit of dead yeast. It is a winemaker’s choice whether to disgorge and fill up the bottles or, more commonly, to keep the light sediment as part of the wine’s style. Typically, no dosage is added in either case.
However, because there is no intervention in the fermentation process once the bottle has been sealed, the outcome can vary. Fermentation will often slow down and stop altogether after a few months because the yeast becomes unviable after this time and due to a lack of yeast nutrients, resulting in an off-dry wine. However, fermentation may start up again later in some bottles. These bottles will have higher pressure and less residual sugar.
While ancestral method was typical of certain areas of France, this method has been revived in small-scale production around the world. It is often called Pet Nat, the abbreviation of Pétillant naturel, and there are no set regulations. The wines are often low in alcohol, slightly cloudy, dry to off-dry with unconventional flavours sometimes compared to cider. They are bottled without additional SO2 and intended for early drinking.
Explain the Tank Method?
The tank method is known by a number of names: Cuve Close, Charmat and Martinotti. It enables large volumes of sparkling wine to be made inexpensively, quickly and with significantly reduced labour costs in comparison to the traditional method. There is no riddling or disgorgement, and typically no dosage or long period on the lees during second fermentation, all of which add cost. In summary, the wines can be made and released for sale quickly. It is generally the preferred method when the winemaker wants to preserve the primary aromas and flavours of the grapes and does not desire autolytic characteristics. It is hence often used for producing fruity wines made with semi-aromatic (e.g. Glera) or aromatic (e.g. Muscat) varieties.
The tank method is often seen as an inferior method of sparkling wine production. This is partly because of the prestige of the traditional method (especially Champagne) and partly because, as an inexpensive method, the quality of the grapes that are used is often lower than those used for traditional method wines.
The first fermentation for tank method wines is typically 16–18°C (61–64°F) to retain fresh floral and fruit aromas and flavours, but avoid the flavours associated with very low fermentation temperatures. Sugar and yeast are added, and a rapid second fermentation takes place in pressurised tanks (also known as reinforced tanks), with the wine remaining in the tank for as little as one month. This fermentation is typically arrested by cooling the wine to 2−4°C (36–40°F) when the desired pressure and residual sugar has been reached. If removed from the yeast lees immediately, the sparkling wines will retain the fruity aromas and flavours.
Occasionally, the wine may be aged on the lees, for example, for nine months if a lees- matured attribute is desired. The temperature is reduced to 2−4°C (36–40°F) and paddles within the tanks are used to stir up the lees to maximise the contact between the lees and the wine. However, because expensive pressurised tanks are then tied up for months, many of the economic advantages of the tank method are lost.
At the end of fermentation or lees contact, the wine is cold stabilised to precipitate tartrates. The yeast is removed by centrifugation or filtration. Sugar levels may be adjusted, and sulfur dioxide levels are checked and corrected prior to sterile filtration and bottling. Wine is chilled to –2°C (28°F) to stabilise and to reduce the effervescence, and then bottled with a counter-pressure filler. (Counter-pressure filling is a system used with other carbonated drinks in which the bottle is first filled with CO2 under pressure. The bottle is then filled with the chilled wine replacing the added CO2. This system prevents the entrance of oxygen and the loss of CO2.)
