Overall winemaking

Question 1

Overall pressing considerations:

Answer 1

• Whole-bunch pressing common for premium traditional method wines.
• Produces delicate juice, low in solids and phenolics (tannins, anthocyanins).
• Stems create juice channels, reducing required pressure.
• More time-consuming than destemmed/crushed fruit due to lower yield and batch processing.
• Pressing must be quick and gentle—especially for black grapes—to avoid extracting unwanted colour and tannin, which can cause bitterness and coarseness.
• Pneumatic and basket presses preferred for gentle, programmable cycles.
• Press fractions often separated:
  • Regulated in some traditional EU regions
  • Aid blending with varied characteristics:
    • Early pressings: more sugar, acid, aromas
    • Later pressings: more phenolics, solids, higher pH
      • Faster maturing—suitable for wines meant for early release

Question 2

Pre-ferment clarification considerations:

Answer 2

juice is clarified before fermentation

any clarification option for still white can be used for sparkling base

excessive tannin or colour at this stage: fining, with casein, gelatine, or PVPP (polyvinylpolypyrrolidone), for example, may be used to clarify juice

Question 3

Primary fermentation: Fermentation temperatures, yeast

Answer 3

• Fermentation temperature: typically 14–20°C (57–68°F)
  • Retains fruit flavours
  • Warm enough for yeast to function
• Low juice pH creates a stressful environment for yeast—temperature shouldn’t add further stress.
• Most fermentations in stainless steel:
  • Large, temperature-controlled tanks
  • Easy to clean before and after fermentation
• Reliable, healthy ferment is critical in sparkling wine production.
• Cultured yeasts preferred:
  • Ferment reliably to dryness in high-acid, low-pH conditions
  • Different strains used for different styles
• Autolytic styles:
  • Neutral yeasts preferred to avoid competing primary flavours
• Non-autolytic styles (e.g. fruity tank method wines):
  • Yeasts that enhance primary flavours (e.g. thiols, esters) often used
• Often same yeast used for both fermentations
• Second fermentation is more stressful:
  
  • Must begin in high-alcohol conditions (10%+ abv)
  • Tolerate low pH, low temperatures, high pressure, and low nutrients

Question 4

traditional method wines, second fermentation: additional attributes of yeast desirable

Answer 4

• ability to autolyse rapidly
• ability to flocculate readily
• flocculation: process by which fine particles, in this case dead yeast cells, clump together.
• ‘Prise de mousse’ (EC1118) one of the most common cultured yeasts used in traditional method
  cultured to survive the second fermentation environment
  provide the processing attributes of rapid autolysis and easy flocculation

Question 5

Malolactic conversion considerations

Answer 5

• Malolactic conversion (MLF) may be used to:
  • Reduce excessive acidity
  • Enhance texture (lactic acid gives a creamier mouthfeel)
• Buttery flavours (diacetyl) usually not present in sparkling wines:
  • Diacetyl is metabolised by yeast during second fermentation
• If MLF doesn’t occur before second fermentation, it may happen in bottle—
  • Problematic for traditional method: causes haze, hard to fix
• If MLF is not desired, wine is typically sterile filtered to remove lactic acid bacteria.

Question 6

Handling base wine overall:

Answer 6

Here’s the revised version in concise bullet points:

• Base wines may be matured before second fermentation, especially for autolytic styles.
• Oak maturation is an option:
  • Usually in old oak; new oak used only in small proportions to avoid dominating flavours
  • New oak can add vanilla, toast, and spice—magnified in sparkling wines
• Lees ageing can occur in oak or neutral vessels to enhance texture and complexity.
• Primary fruit styles (e.g. Prosecco) typically not matured in oak.

Question 7

Post-fermentation clarification: Fining, filtering

Answer 7

Here’s the revised version in concise bullet points:

• Juice clarification occurs before fermentation.
  • Same clarification methods used for still white wines can be applied to sparkling base.
  • If excessive tannin or colour, fining agents like casein, gelatine, or PVPP may be used.
• Blending:
  • For traditional method, base wine should be stabilised for tartrates and proteins before second fermentation.
• For all methods, juice should be clarified before second fermentation using techniques common in still wine production.

Question 8

Blending: Reasons for blending, reserve wines
overall considerations

Answer 8

Here’s your revised version in concise bullet points:

• Blending of base wines from:
  • Different vineyard sites
  • varieties
  • vintages
  • winemaking techniques
    key in sparkling wine production
• Reasons for blending:
  • Balance: Pinot Noir adds body, Chardonnay adds acidity; blending from warmer/cooler sites helps manage acidity.
• Consistency:
  
  • Non-vintage blends ensure a consistent product year after year.
• Style:
  
  • Early-drinking, approachable styles have ripe fruit and lower acidity.
  • Wines for longer ageing have more concentrated flavours and higher acidity.
  • Rosé wines made by blending red and white base wines.
• Complexity:
  
  • Blending different varieties, vineyard sites, and vintages adds a range of flavours.
  • Older vintages add dried fruit notes to fresh fruit of current vintages.
  • Blending wines treated differently (e.g., oak vs. no oak) adds complexity.
• Minimisation of faults:
• Minor faults in a batch can be corrected by blending (e.g., higher VA blended with lower VA).
• Volume: Small vineyard holdings may blend wines from multiple growers to increase production.
• Price:
  • Cheaper varieties (e.g., Meunier) blended with prestigious ones (Chardonnay, Pinot Noir) to maintain affordability while benefiting from well-known names.
  • More second/third pressings used in cheaper blends to reduce costs.

Question 9

Secondary fermentation: Fermentation temperature, yeast, stopping fermentation, type of vessel, time on lees, disgorgement

Answer 9

• Prise de mousse (“capturing the sparkle”):
  • Second fermentation in the same bottle for traditional method sparkling wines.
  • Liqueur de tirage added to base wine:
    • Mixture of wine, must, sugar, cultured yeasts, yeast nutrients, and clarifying agents (e.g., bentonite, alginate).
• Sugar addition:
  • Amount depends on required effervescence; typically 24 g/L sucrose added for fully sparkling wines.
  • 24 g/L generates about 1.5% abv and creates CO2, increasing bottle pressure (6 bars).
  • Less sugar = lower pressure.
  • Sugar does not affect sweetness; yeast ferments to dryness.
• Yeast:
  • Strains can ferment in unfavourable conditions (9.5–11% abv, 16˚C/61˚F, pH <3) and withstand high pressure to complete fermentation in the bottle.
• Bottling and storage:
  • Bottled with a crown cap and small plastic pot to catch sediment.
  • Stored horizontally at a stable temperature of 10–12˚C (50–54˚F) to avoid adding stress to yeast.
  • Fermentation lasts 4–6 weeks, slower at cooler temperatures (cooler fermentations may produce more complex wines).
• After fermentation:
  • Yeast cells flocculate to form sediment, which is removed by riddling.

Question 10

Lees: define, describe, time

Answer 10

• Autolysis:
  • Enzymatic breakdown of dead yeast cells, releasing aromas/flavours like brioche and biscuit.
  • Typically continues for 4-5 years, may last up to 10 years.
  • Bottles stored horizontally at around 10˚C (50˚F), in stacks or metal cages.
• Lees ageing:
  • Effects more pronounced after the first year.
  • In rare cases, autolysis can continue for up to 10 years.
• Factors influencing ageing length:
  • EU legislation:
    • Cava de Guarda must age for at least 9 months on lees.
    • NV Champagne must age for at least 12 months on lees.
  • Desired style: fruitier vs. more lees-aged character.
  • Price: longer lees ageing increases cost.
  • Producer’s ability to invest in longer lees ageing, tying up inventory costs.
• Post-autolysis lees ageing:
  • Yeast’s antioxidant qualities protect the wine.
  • Longer lees ageing speeds up evolution once disgorged.
  • Older wines are more sensitive to oxygen during disgorgement.
• Example: Bollinger ‘R.D.’ is intended to be consumed soon after disgorgement.

Question 11

Riddling and Disgogement

Answer 11

Here’s the concise version in bullet points:

• After ageing:
  • Bottles placed in riddling racks (pupitres) for hand riddling (8 weeks) or in gyropalettes (computer-controlled, 3-4 days) for faster riddling.
  • Hand riddling: Slow process with gradual rotation.
  • Gyropalettes: Vibration and movement from horizontal to vertical position.
  • Pre-disgorgement storage: Bottles stored upside down (sur pointe) to keep lees in the neck.
• Disgorgement process:
  • Removal of yeast with minimal wine and pressure loss, done by hand or automated.
  • Bottles cooled to approx. 7˚C to reduce gushing risk.
  • Necks immersed in frozen brine to freeze yeast sediment, ensuring it doesn’t fall back.
  • Disgorging machine: Inverts bottle, removes crown, ejects frozen yeast.
  • Liqueur d’expédition added, bottle sealed with cork, wire muzzle, and metal capsule.

Question 12

The liqueur d’expédition:

Answer 12

Here’s the concise version in bullet points:

• Dosage: Mixture of wine and sugar or RCGM (rectified concentrated grape must), used to top up the bottle after some loss.
  • Determines the sweetness of the wine.
• Trend: Growing popularity of Brut Nature (no dosage) and Extra Brut (less than 6 g/L sugar).
• Role of dosage:
  • Balances acidity, especially in younger wines.
  • Older wines require smaller dosages at disgorgement.
  • Sugar reacts with yeast autolysis compounds (Maillard reaction), developing roasted, toasted vanilla aromas.
• Storage: Cork-sealed wines may be stored a few extra months to develop these post-disgorgement aromas.
• Labelling: Most sparkling wines use EU’s official labelling terms for sweetness.

Question 13

TRANSFER METHOD description

Answer 13

• Developed in the 1940s to avoid the cost of manual riddling while retaining autolysis flavours (brioche/biscuit).
• Process:
  • Same as traditional method until riddling.
  • Second fermentation occurs in the bottle, but not the same bottle sold.
  • No riddling, so fining and flocculation agents are not added to the tirage liqueur.
• After lees ageing:
  • Bottles chilled to 0ºC, opened in a transfer machine.
  • Wine poured into pressurised receiving tanks to maintain CO2.
  • Final treatments: dosage, SO2 top-up, sterile filtration before bottling.
• Labeling: Not typically labeled as “Traditional method,” but “Fermented in bottle.”
• Benefits:
  • Reduces bottle-to-bottle variation by blending.
  • Easier final adjustments, more consistent.
  • Cost and time-saving (no manual riddling needed).
  • Automated riddling makes benefits of manual riddling less significant.
• Usage: Common in Champagne and other regions, especially for bottle sizes smaller than 37.5 cL or larger than 300 cL (difficult to riddle).

Question 14

ANCESTRAL METHOD description

Answer 14

Here’s the concise version in bullet points:

• Fermentation Process:
  • Partly fermented must is placed into bottles.
  • Remaining sugar is converted into alcohol and CO2.
  • Sugar levels can be measured accurately to estimate final pressure.
  • Fermentation in the bottle creates a deposit of dead yeast.
• Winemaker’s choice:
  • Disgorge and top up or keep light sediment as part of the wine’s style.
  • Typically, no dosage is added in either case.
  • No intervention once sealed, leading to variable outcomes.
• Fermentation characteristics:
  • Often slows or stops after a few months; yeast become unviable.
  • Lack of yeast nutrients can result in an off-dry wine.
  • Some bottles may ferment later, with higher pressure and less residual sugar (RS).
• Style:
  • Low to medium alcohol, slightly cloudy, dry to off-dry.
  • Unconventional flavours, sometimes compared to cider.
  • Bottled without additional SO2, for early drinking.
• Term: Often called Pet Nat (Pétillant naturel), revived in small-scale production worldwide.
• No set regulations for production.

Question 15

TANK METHOD description

Answer 15

• Cuve Close, Charmat, Martinotti methods:
  • Designed for large volumes, quick production, and reduced labour costs compared to the traditional method.
  • No riddling or disgorgement.
  • Typically no dosage or long lees aging during second fermentation.
  • Wines are made and released quickly.
  • Preserves primary aromas, not autolytic characters.
  • Preferred for fruity wines made from semi-aromatic (e.g., Glera) or aromatic (e.g., Muscat) varieties.
  • Often seen as inferior to the traditional method (e.g., Champagne).
  • Typically uses lower-quality grapes.
• First Fermentation:
  • Occurs at 16–18°C to retain fresh, floral, and fruit aromas.
  • Avoids undesirable flavours from very low fermentation temperatures.
  • Most esters produced (e.g., banana, apple, pineapple) are unstable and break down after a few months.
• Second Fermentation:
  • Sugar and yeast added for rapid fermentation in pressurised tanks (“reinforced tanks”).
  • Ferments in tank for as little as one month, arrested by cooling to 2−4°C when desired pressure and residual sugar (RS) are reached.
  • Yeast lees are removed immediately to retain fruity aromas.
  • Occasionally aged on lees (e.g., nine months) for desired attribute.
  • Disadvantage: Expensive pressurised tanks tied up for months can reduce economic benefits.
• Stabilisation:
  • Cold stabilisation to precipitate tartrates.
  • Yeast removed by centrifugation or filtration.
  • Sugar and SO2 levels adjusted and sterile filtered.
• Bottling:
  • Wine chilled to –2°C to stabilise and reduce effervescence.
  • Bottled with counter-pressure filler:
    • Bottle first filled with CO2 under pressure.
    • Chilled wine replaces added CO2 to prevent oxygen and CO2 loss.

Question 16

ASTI METHOD description

Answer 16

• Variation Tank Method:
  • Single fermentation process.
  • Sugar comes from the original must, not added in tirage.
  • Must is fermented in reinforced tanks.
  • First stages: CO2 escapes through a valve.
  • Valve is closed at a certain point to retain CO2.
  • Timing:
    • Desired pressure and sugar levels are reached.
    • Fermentation continues until sugar decreases and pressure increases.
  • Stopping fermentation:
    • When desired sugar levels are obtained, fermentation is stopped by rapidly chilling the wine and filtering under pressure to remove yeast.

Question 17

Carbonation description

Answer 17

• CO2 Injection Method:
  • Least expensive and least prestigious method.
  • CO2 is injected into the wine, causing bubbles that may dissipate quickly in fully sparkling wines.
  • Works best for pétillant or lower pressure wines.
  • Advantages:
    • Preserves the aroma and flavour characteristics of the base wine.
    • Suitable for aromatic or fruity wines.
    • Good quality base wine is important, as faults will be more noticeable with bubbles.

Question 18

Overall finishing options: dosage, packaging, closures

Answer 18

Here’s the concise version in bullet points:

• Classic Cork Sealing Method:
  • Cork shape: After sealing, it has a mushroom shape.
  • Pre-bottling: Cork diameter is about 31 mm.
  • Often made from agglomerate cork with two glued natural cork disks (1+1 cork).
  • Compression: Cork compressed by machine jaws to 60–70% of its original diameter, then inserted into the bottleneck.
  • Cork expands inside the bottle neck (18–21 mm diameter) to prevent leakage.
  • Recent technology: Reduced cork taint aromas, leading to the use of technical corks like DIAM.
  • Some ancestral method producers use crown caps for informal styling.
  • A few mass-market brands (e.g., Yellow Tail) have trialled synthetic closures with resealing mechanisms.
  • Despite alternatives, cork remains the preferred choice for sparkling wines.

Question 19

Sweetness terms in EU

Answer 19