Standard Options in Sparkling Winemaking Flashcards
1
Q
Grapes for sparkling wine
A
- Just-ripe in flavour
- High acidity required for high-quality
- Sugar accumulates slowly
- Base wines with low alcohol (9-11% abv) - second fermentation produces 1-2% abv.
2
Q
Regions were grapes for sparkling wines tend to be grown
A
- Cool climates
- Greater latitudes [Champange, England Tasmania]
Local cooling influences near the coast [Sonoma] or at high altitude [Trentodoc] - Less intense fruit flavours are usually preferable to make elegant, balanced, long-lees-aged sparkling wines
3
Q
Cooler areas VS warmer areas
A
- In warmes areas, the grapes tend to have riper fruit flavours and lower acidity compared to grapes grown in cooler sites. This could be desirable for short-aged wines (e.g. those made by tank method or with short time on lees in transfer or traditional method), as the fruit will provide the only or dominant flavours.
- Less intense fruit flavours are usually preferable to make elegant, balanced, long-lees-aged sparkling wines
4
Q
Chardonnay
A
- Well suited to the production of autolytic styles of sparkling wines.
- Subtle apple and citrus aromas and flavours compliment rather than compete with the biscuit or pastry aromas from yeast autolysis.
- 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.
- Brings apple and citrus flavours and high acidity to the blend.
- Being early budding, it is vulnerable to spring frosts.
- It is prone to coulure and millerandage.
- More disease resistance than PN, but it 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.
5
Q
Pinot Noir
A
- 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.
6
Q
Factors within the grape variety that can influence the style of the wine
A
- 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.
7
Q
GRAPE GROWING
A
- 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. - The perception of any off-flavours from diseased fruit can be enhanced by the effects of effervescence in the wine.
- The enzyme laccase released by botrytis-infected grapes can cause serious oxidation.
8
Q
HARVESTING
A
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.
9
Q
HAND HARVEST VS. MACHINE HARVEST
A
- Hand harvesting and machine harvesting are both used for sparkling wine production, depending on location and local wine laws.
- AD. 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 pigment and tannin extraction. - DIS. Hand harvesting is slow, labour-intensive and can be expensive.
DIS. - Machine harvesting can rupture the skin of the grapes, resulting in phenolic extraction and oxidation. AD, However, the advantages of machine harvesting are that it is faster, cheaper and permits night-time harvesting, thus delivering cooler grapes. Diseased or damaged grapes can be removed by hand just prior to machine harvest. Cooler grapes are an advantage because oxidation is slowed down, resulting in
fresher wines.
10
Q
PRESSING
A
- 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.
- However, for all sparkling wines, it is important to minimise the amount of phenolic compounds in the juice. These 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.
- Nutrients provided by a certain amount of grape solids are required for healthy first and second fermentations. 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.
11
Q
PRIMARY FERMENTATION
A
- Fermentation temperatures of 14–20°C 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 which 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. Selected 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, these 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 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) and 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. - The yeast called ‘Prise de mousse’ (EC1118) is one
of the most common commercially-available yeasts. - 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. This would be difficult to rectify in the bottle. Therefore, if malolactic conversion is not desired, the wine may be sterile-filtered.
12
Q
HANDLING OF THE BASE WINE
A
- 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. - 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.
13
Q
PURPOSE ASSEMBLAGE (BLENDING)
A
- 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 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, 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.
14
Q
TRADITIONAL METHOD - Second fermentation
A
– 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 sugar, selected 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, enough liqueur de tirage is added to supply about 24 g of sucrose per litre.
- During fermentation, the yeast converts the sugar to alcohol (about +1.5 per cent for an addition of 24 g/L)
and CO . Unable to escape from the bottle, the CO 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 specially selected sparkling wine yeast. 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 and pH values often below 3, and later withstanding high pressure fermentation in 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.
15
Q
TRADITIONAL METHOD - Lees ageing
A
- After fermentation, the producer may choose to age the wines before removing the yeast. The bottles can be stored horizontally in freestanding stacks or in gyropalettes, 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
biscuity 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.
