WSET Level 3 Lecture #3: Human Influences in the Winery (Wine Theory)

This post summarises the theory lecture on 18-Jan-2017, the third of the 15 lectures from WSET Level 3 course which runs from 4-Jan-17 to 19-Apr-17. The tasting part will be covered separately in the next post.

In addition, I inserted relevant YouTube video clips in this post that will help your understanding, especially if you have no background knowledge in viticulture, like me!

1. Common Elements in Winemaking and Maturation 

1.1. Common elements throughout winemaking and maturation

  1. Oxygen (O2)

    1. Oxidation
      • Oxygen can react with grape juice as well as with many components of wine in a positive or negative way
    2. Oxygen in winemaking
      • Can be a threat if the aim is to make a wine dominated by primary fruit characteristics
      • Methods to counter this threat:
        • antioxidants such as sulfur dioxide is used
        • grapes are picked at night and kept chilled at the winery (lower temperature means slower chemical reactions)
        • fill the container with carbon dioxide or nitrogen
    3. Oxygen in maturation
      • If kept away from oxygen during winemaking to preserve fruity character, the same is necessary for maturation – these wines are stored in inert airtight tanks (stainless steel, cement lined with epoxy resin) and kept completely full.
      • Aerobic maturation (in contact with oxygen): wooden vessels used (normally oak) 
        • can help to soften tannins
        • more complexity to the flavour – primary fruit flavours fades and tertiary characters (leather, earth) develop
        • colour (red wine): paler with hint of brown
        • colour (white wine): deeper with hint of orange
        • smaller vessels (225-litre barriques): more surface contact with oxygen per quantity, thus greater oxidative effect
        • deliberate oxidation with not completely full containers (Sherry or Port making): pronounced tertiary characters of caramel, toffee and coffee
  2. Sulphur Dioxide (SO2)

    1. Usage in winery
      • Indispensable as an antioxidant & antiseptic
      • Protects freshly harvested grapes from oxidation and contamination
      • Max. level strictly controlled by law as it can be toxic
      • keeping additions as low as possible is desirable as wine may taste harsh and lacking fruit flavour
    2.  Antioxidant
      • Protects the grape juice and wine from unwanted oxidation
      • Yet, in the process, it loses the ability to protect and becomes ‘bound’
      • Thus, level of SO2 need constant monitoring & replenishing
    3. Antiseptic
      • Toxic to many unwanted yeast and bacteria that can cause bad flavours to wines
      • Fortunately, the principal yeast involved in the alcoholic fermentation can tolerate better
  3. Oak Vessels

    1. Benefits
      • Allow a small level of desirable oxidation
      • Add secondary (toast, vanilla, smoke and cloves) aromas and tannin (textural complexity)
      • Allow tertiary (almond, coffee, toffee, caramel) aromas to develop
      • Beware of hygiene issues (yeasts, bacteria and moulds) or tainted woods
    2. Species and origin of oak
      • Different species have different characteristics
      • Even same species can show different characteristics depending on the origin
      • European oak: savoury
      • American oak: more sweet flavour
    3. Size
      • Smaller vessels have much greater effect (225-litre barrique, 228-litre pièce)
      • More of the wine is in contact with the surface of the barrel
    4. Production of oak barrels
      • Toasting: to bend the wood into shape, adding the flavour of sweet spice and toast
      • Level of toasting: the temperature and length of heat exposure
    5. Age
      • The effect of toasting diminishes each time the barrel is used
      • By the fourth usage, it imparts little flavour and tannin
      • Brand new barrel: more flavour and tannin, maybe too strong for some wine styles
  4. Oak alternatives

    1. Staves: small planks of oak
    2. Chips: even smaller oak pieces
    3. Not used for premium wines, yet much cheaper way to add some oak aromas and tannins
  5. Inert winery vessel

    Do not add flavour & no oxidation, hence ‘inert’

    1. Stainless steel
      • Easy to keep clean
      • Can be made in any shapes and sizes
      • Can incorporate temperature control mechanisms 
    2. Concrete vessels
      • Lined with epoxy resin – inert & waterproof
      • Can be less easy to clean and maintain than stainless steel
      • Yet, thick concrete shells help regulate temperature
      • Can allow small amount of oxidation without epoxy resin lining 

Video: Discover the Art of Making Wine – LCBO Broadcast Production Group

1.2. Grape processing

  1. Grape reception

    1. Protect the fruit with SO2
    2. Grape sorting (optional): to eliminate unripe/rotten grapes for premium wines
  2. Destemming & Crushing

    1. Stems removed mostly (optional), or already removed if harvested by machines
    2. Crushing breaks the skins of the grapes and liberates a quantity of juice (aka ‘free run juice)
    3. Beware of damaging the seeds during crushing as they will release bitter oils and tannin
  3. Pressing

    1. Pressing separates the liquid and the solid constituents of the grapes (skins, seeds, etc.)
    2. White wines: pressing happens before fermentation
    3. Red wines: pressing typically happens after fermentation (i.e. ferment with the skins)
    4. Vertical ‘basket’ press: more traditional
    5. Pneumatic press: more recent development, to apply pressure over a larger area, in a controlled way

1.3. Adjustments

Adjustments can be made before, during or after fermentation for a variety of reasons. Grape juice is referred to as ‘must’.

  1. Sugar & Alcohol

    1. Cooler climates: insufficient natural sugar in grapes to give wine a satisfactory level of alcohol
    2. Must weight: level of sugar in the grape juice
    3. RCGM (Rectified Concentrated Grape Must): colourless, odourless syrupy liquid
    4. Enrichment: adding RCGM can raise the level of alcohol in the final wine after fermentation
      • Yet, enrichment is forbidden in many parts of the world, or strictly controlled even if allowed
    5. Chaptalisation: adding sugar from sources other than grapes
    6. Removal of water: could be an option, yet the quantity of wine is reduced and any faults can be magnified
  2. Acid

    1. Hot climates or over-ripe grapes: grape acidity may fall too far
    2. Acidification: addition of tartaric acid in powder form
    3. Europe: this is permitted in warmer regions only (i.e. Spain)
    4. Common in many warm and hot regions around the world
    5. Deacidification: more common in cooler climates by addition of an alkali

1.4. Fermentation

  1. Alcoholic Fermentation

    1. Yeast (Saccharomyces cerevisiae) converts sugar into alcohol and CO
    2. By-products of alcoholic fermentation: heat & flavour compounds
    3. Temperatures between 5°C to 35°C: if too low or too high, fermentation will not take place
    4.  If sugar level is too high, yeast may struggle to start fermentation
    5. Fermentation can be controlled by yeast and temperature
      • Yeast
        • ambient yeast: (on the grape bloom or in the winery) may produce complex flavours, but cannot control the outcome
        • cultured yeast: (individual strains of Saccharomyces cerevisiae) consistently produce desired flavours
      • Temperature
        • too hot, yeast will be killed
        • can influence the flavour and style of the wine being made
        • fermentation at lower temperature: can keep the most volatile aromas (floral) and encourage fruity flavours in white wines
        • fermentation at higher temperature: necessary to extract colour and tannin for red wines
  2. Malolactic Fermentation (MLF)

    1. Usually takes place after alcoholic fermentation
    2. Carried out by lactic acid bacteria, converting the tart malic grape acid into the softer lactic acid
    3. MLF softens and reduces acidity and creates buttery flavour
    4. MLF may be encouraged by raising the temperature and by not adding SO2

1.5. Pre-bottling maturation & blending

Video: Jordan Winery – Bâtonnage (lees stirring)
 
Video: Bâtonnage (lees stirring) – Using barrel rollers
 

  1.  Lees

    1. Right after fermentation, wine can appear cloudy due to dead yeast cells and grape fragments
    2. Gross lees: these suspended particles that fall to the bottom of a vessel. If not removed, it can cause unpleasant aromas to develop in the wine
    3. Fine lees: smaller particles that settle more slowly
    4. Lees contact: in some cases the winemaker may choose to keep a white wine in contact with the fine lees during pre-bottling maturation (see the video above)
    5. This will add extra flavours and a richer texture to the wine
  2. Pre-bottling Maturation

    1. Not every wine benefits from an extended period of maturation before bottling, especially if the aim is to retain as many of the primary fruit aromas as possible
    2. This process can add oak flavours and/or allow oxidation
  3. Blending

    Blending plays a vital role for virtually every wine, including the single grape variety wines. It can take place at any stage during winemaking process, but is mainly carried out after fermentation or during the maturation. Yet, there may be constraints imposed by local winemaking regulations.

    1. Balance: blending allows the winemaker to adjust the balance of the wine, enhancing its quality (tannin, acidity, etc.)
    2. Consistency: To avoid any noticeable variation among the bottles of a single wine
    3. Style: To achieve and maintain a certain house style by using wines from different grape varieties, vineyard plots and vintages

1.6. Clarification

  1. Sedimentation

    1. Most wines go through sedimentation after the fermentation
    2. Racking: wines to be slowly and gently pumpedinto a different vessle leaving the sediment behind
    3. Sedimentation relies on gravity to pull the suspended particles to the bottom
  2. Fining

    1. To accelerate wine constituents to clump together, so that it can be removed
    2. This involves adding a fining agent to the wine
  3. Filtration

    1. This process physically removes particles from a wine as it is passed through a filter, usually before bottling
      • Depth filtration: using a thick layer of material to handle very cloudy wines and to remove gross lees
      • Surface filtration: resemble very fine sieves, normally after passing depth filters

1.7. Stabilisation

A wine is considered stable if, over a specified time frame, it changes in a slow, predictable manner. 

  1. Tartrate Stability

    1. Tartaric acid is less soluble in wine than in a grape juice
    2. Tartrates: crystals formed from tartaric acid, harmless and flavourless, yet customers do not want these
    3. Cool temperatures accelerate the formation of tartrate crystals
    4. Winemakers can force the crystals to form prior to bottling by chilling the wine down to below 0°C for a short period and remove these by filtration
  2. Microbilogical Stability

    1. Many different forms of yeast and bacteria can spoil a wine
    2. Low risk wines: fortified wines, a dry, high acidity wine that undergone MLF
    3. High risk wines: wines that have not undergone MLF, low to medium alcohol, low acidity and a little residual sugar
    4. Appropriate amount of SO2, careful handling and sterile filtering can avoid this
  3. Oxygen Stability

    1. Excessive levels of oxygen dissolved in the wine or oxygen entering through packaging can lead to oxidation
    2. This will result the loss of fresh fruit aromas, and the wine will gradually turn brown
    3. Avoid exposure to oxygen and keep SOlevels topped up, or bottles can be flushed with CO2 or nitrogen before filling

1.8. Packaging

  1. Bottles & Alternatives

    1. Glass: cheap, quite strong, do not allow air to get into the wine, but heavy and rigid
    2. Plastic: much lighter, but allow small amounts of air to pass through
    3. Glass is the best option for long-term storage and ageing
  2. Closures

    1. Tertiary flavour development: a slow entry of very small amounts of oxygen needed
    2. Retaining primary fresh and fruity flavours: avoid any contact with oxygen
    3. Cork: the original wine bottle closure, allowing a small amount of oxygen gradually enter the bottle, thus suitable for bottle maturation
      • Optimal choice to achieve balance between primary and tertiary characteristics
      • Cork taint: too much oxidation caused by a chemical called TCA (trichloroanisole) – mouldy, cardboard-like aroma
    4. Synthetic corks: some form of plastic
    5. Screw caps: free from taint and provides an impermeable seal from the air
      • Can preserve the fruit flavour longer than cork

1.9. Post-bottling maturation

Majority of wines are consumed within a year of bottling. Yet, many wines can mature in a bottle for several years such as Vintage Port or the finest German Riesling. 

  1. Ageing conditions

    1. Cool dark place, constant temperature around 10-15°C, constant humidity, bottles stored lying on their side if sealed with cork

 

2. White & Sweet Winemaking

2.1. Important Options in White Winemaking

  1. Skin Contact

    1. In most cases, the juice spends little time in contact with skins to reduce the risk of oxidation
    2. To limit the contact even further, some winemakers choose to load the press with whole bunches of uncrushed grapes
    3. Yet, for certain aromatic varieties, some winemakers choose to keep the juice in contact with the skins for a short period to increase flavour intensity and texture
      • This happens at a sufficiently cool temperature to inhibit fermentation, and only up to a few hours
  2. Clarity of the Juice

    1. Freshly pressed grape juice contains fragments from  the grape skins and the pulp that can cause unpleasant aromas if fermented as is, and even lead to premature fermentation
    2. Thus, same techniques to clarify wines before bottling are used
      • Settling, centrifugation, fining and filtration
    3. Yet, rarely, some winemakers choose to retain a small amount of these fragments
      • This can make the finished wine less susceptible to oxidation
      • And this can add complexity and richer texture
      • However, this is not recommended for wines intended to show a pure varietal character
  3. Fermentation Temperature & Vessel

    1. White wine fermentation temperature: 12°C – 22°C
      • Too low temperature: develop aromas of pear drop and fail to capture varietal fruit characters
      • Too high temperature: can encourage to develop more complex, non-fruit aromas, yet varietal fruit characters will be lost
    2. Stainless steel vessels: easier to control temperature
    3. Barrels: not so easy, thus shall be placed in a cool place and normally fermented at a higher temperature
  4. Post-fermentation & Maturation options

    1. Vessel for maturation: Oak or inert vessel (with or without oak staves or chips)
    2. Lees contact: let the wine contact fine lees to add texture and flavour or not
    3. MLF: allow it or block it
  5. Blending

    1. Aims: to improve consistency, enhance the balance, and create a certain style
      • Many white wines based on pure primary fruit flavours: blending is focused on ensuring consistency
      • The reverse may be true for some non-aromatic varieties such as Chardonnay: blending to create a certain style
  6. Clarification & Stabilisation

    1. Aim: to improve the clarity and stability

2.2. Producing High-volume, Inexpensive White Wines

  1. Common themes

    1. Fairly neutral flavours: Chardonnay & Pinot Grigio
    2. Easier to make high volumes by blending different grape varieties
    3. Chardonnay
      • Unoaked style: pure fruity flavours such as peach and melon
      • Oaked style: additional flavours such as vanilla and toast
    4. Pinot Grigio 
      • Usually unoaked style, with like pear drop aromas and flavours, light body and medium acidity
  2. Winemaking Choices

    1. Avoid oxidation: To retain pure, simple primary fruit flavours
    2. Acidification: most common adjustment for grapes grown in warm or hot regions
    3. Clarification: To ensure fruity flavours are retained during fermentation
    4. Fermentation vessel: Stainless steel
    5. Fermentation temperature: Cool
    6. Yeast: commercial yeast to ensure a quick, reliable fermentation
    7. MLF: avoided by chilling the wine and adding SO2 by chi to retain acidity and primary fruit aromas
    8. Stabilisation, sterilisation, filtration

2.3. Producing Premium White Wines

The aim is to make high-quality wine, often at the expense of volume. Winemaking techniques are adapted according to vintage conditions, vineyard plot, and the style of wine

  1. Aromatic Grape Varieties: Sauvignon Blanc & Riesling

    1. Sauvignon Blanc: highly aromatic, high acidity
      • Early ripening: suitable for cool climates
      • Loire (Sancerre, Pouilly-Fumé) of France: green apple, asparagus
      • Marlborough of New Zealand: cool climate with ample sunshine: gooseberry, elderflower, grapefruit, passion fruit
      • Best drunk young while intense fruit flavours are still fresh
      • Pessac-Léognan: different approach using oak and barrel fermented, for rounder body and spicy toasty note, and blended with Sémillon
      • Fumé Blanc in California: barrel fermented to create the creamy and spicy style
    2. Riesling: capable of producing a variety of styles, ability to mature
      • Tolerant of cold winters and late budding: can avoid spring frosts and suitable for cool climates
      • Mid to late ripening: capable of producing a variety of styles
      • Cool climates: green fruit, floral notes
      • Warmer climates: citrus, stone fruit
      • Maturation: most long-lived white wines, developing honey and toast flavours, while retaining high acidity
      • Can develop Petrol-like aromas 
      • Germany: range of sweetness levels, 
      • Alsace: mostly dry Riesling
      • Austria
      • Clare Valley, Eden Valley of Australia: bone dry, refreshing high acidity, lime aromas
    3. Other varieties: Muscat, Gewurztaminer, Torrontés
    4. Winemaking Choices: main aim is to retain the fruit and floral aromas
      • SO2 levels must be monitored and maintained
      • Clean juice before fermentation 
      • Inert vessels, mostly stainless steel
      • Temperature for fermentation: cool
      • Premium sweet Riesling: stopping the fermentation either by chilling or adding SO2
      • Sweetest Riesling: botrytised grapes and fermentation stops naturally
      • High acidity desirable: stop MLF by adding SO2
      • Bottling right after fermentation to keep aromatic characters
  2. Less aromatic Grape Varieties: Chardonnay & Pinot Gris/Grigio

    1. More neutral in aroma and flavour can be very positive for winemakers as they can play more active role to influence the end product
    2. Chardonnay: can be grown in wide variety of climates with subtle aromas make it a perfect blank canvas
      • Early budding: risk of spring frost in cool climates
      • Cool climates: green fruit, citrus
      • More moderate climates: white peach, melon
      • Warm & hot climates: banana, pineapple – can lose acidity quickly towards the end of the ripening, thus timing of harvest is key
      • Chablis: high acidity, green apple, citrus, hint of wet stone
      • Côte-d’Or: stone fruit, creamy oak
      • Mâconnais: Ripe fruit, toasty oak
      • Most producers use MLF and extended lees ageing – best wines develop complex nut and/or mushroom aromas
      • Russian River Valley, Los Carneros in California
      • Adelaide Hills, Geelong, Mornington Peninsula in Australia
      • Gisborne, Marlborough in New Zealand
      • Casablanca Valley in Chile
    3. Pinot Gris/Grigio: French/Italian
      • Early budding & ripening
      • Alsace: dry or off-dry, oily texture, ripe tropical fruit, hint of ginger and honey, viscous mouthfeel, medium acidity
      • Similar Pinot Gris styles found in New Zealand, Tasmania in Australia and Oregon, USA
      • Alto Adige, Trentino, Friuli-Venezia in north-east Italy: high quality Pinot Grigio in dry style
    4. Winemaking Choices
      • Oxidation in a controlled manner
      • Clarification less critical than aromatic wines, some solids may be left in the juice for added complexity and texture
      • Vessels: Stainless steel to retain fresh fruit (Chablis), Old oak vessels in Alsace Pinot Gris, Small new oak barrels in Côte-d’Or
      • Even greater range of options after fermentation
        • New oak barriques: Côte-d’Or, New World for toasty flavours
        • Older oak & larger barrels: Chablis, Alsace to allow gentle oxidation and promote complexity
        • MLF may be encouraged, especially for most of the premium wines of Burgundy, including Chablis
        • Yet, MLF decreases the perception of acidity and diminishes primary fruit flavour
        • Fine lees contact via lees stirring (Bâtonnage): richer and rounder mouthfeel
      • Premium Chardonnay and Pinot Gris are not usually blended

 2.4. Sweet Winemaking

Sweet wines contain unfermented sugar and this can be achieved in a number of ways

  1. Stopping the Fermentation

    1. Fortification: by adding alcohol and killing the yeast
    2. Adding a high dose of SO2 / Chilling the fermenting wine: wines with low alcohol
      • high quality German Kabinett & Spätlese, Asti from Italy
  2. Adding a Sweetening Component

    1. Adding grape juice
      • (Germany: Süssreserve)
      • RCGM (Rectified Concentrated Grape Must)
  3. Concentrating Grape Sugars

    1. Noble rot: method used for the very best sweet wines
      • Sauternes, Takaji, Beerenauslesen, Trockenbeerenauslesen
      • Distinctive honey, apricot, citrus zest and dried fruit aromas
      • Several pickings and selections needed by skilled labour
      • Sometimes labelled as ‘botrytised’
      • Caused by the fungus Botrytis cinerea when,
        • grapes must be fully ripe before the development of rot
        • humid misty mornings to develop the rot: fungus punctures the grape skin
        • followed by a sunny dry afternoons: slows the rot and cause water to evaporate from the grape, concentrating its acid, flavours and sugar
    2. Drying grapes on the vine: Passerillage
      • Turn to raisins on the vine, after full sugar ripeness
      • Warm dry autums needed
      • Overripe fruit character: dried fruit, tropical fruits, richly textured mouthfeel
      • Sometimes labelled as ‘late harvest’
    3. Drying grapes after picking
      • Passito wines of Italy: Recioto della Valpolicella DOCG
      • Raisiny quality
    4. Freezing grapes on the vine
      • Water in the grape pulp turns into ice
      • When grapes and picked and pressed, this ice remains in the press and the sugar content of the resulting juice increases
      • Very pure varietal character
      • Eiswein in Germany
      • Icewine in Canada

 

3. Red & Rosé Winemaking

  • The key to red winemaking: the successful extraction of colour and tannin from the skins of black grapes, achieved by including the skins in the fermentation vessel
  • More options to consider before, during and after the fermentation than white winemaking
  • Pressing happens after the fermentation
  • MLF is a standard practice rather than a stylistic choice as in white winemaking

3.1. Crushed Fruit Fermentation

  • The vast majority of fruit used in red winemaking is destemmed and crushed
  • This technique is used for the destemmed and crushed fruit
  1. Pre-fermentation Extraction

    1. Cold maceration: leave the grapes to macerate for a period at a low temperature before fermentation to extract colour and flavour (aka cold soaking)
    2. Tannins are more soluble in alcoholic solutions, thus not readily extracted at this point
  2. Temperature Control during Fermentation

    1. Temperature range for red wine fermentation: 20°C – 32°C, depending on the style of the wine being made
    2. Higher than white winemaking to extract colour flavour and tannin
    3. Precise temperature control during fermentation can allow the winemaker to influence the amount of colour, flavour and tannin that are extracted
    4. Careful not to exceed 35°C, as this may kill the yeast
  3. Cap Management Techniques

    1. Cap: a thick mass of pulp and skins on a surface during fermentation
      • If the cap is left to float, little colour, flavour or tannin will be extracted from it
      • Level of extraction can be controlled by altering the duration of each technique and the number of times this is practised each day
    2. Punching down
      • Punching the cap down
      • Very effective at extracting colour and tannin
      • Care needed not to overwork the cap, especially at the end of the fermentation when the tannins are more easily extracted
    3. Pumping over
      • Drawing off fermenting juice from the bottom of the vat and pumping it up on to the top, wetting the cap
      • Popular method and good way of dissipating heat as well as oxidisng the juice
    4. Rack and return
      • The fermenting juice is drained from the fermenting vessel to another vessel, leaving the cap behind – then the juice is pumped back over the cap
      • Only used once or twice during fermentation as this can be very extractive, also good way of dissipating heat
    5. Rotary fermenters
      • Rotaing horizontal tanks used for fermentation, keeping the juice in constant contact with the skins
  4. Fermentation Vessels

    1. To use cap management techniques, usually large vessels are used for fermentation
    2. Fermentation in oak barrels is impractical for red wines
      • impractical to maintain sufficient contact between the skins and the juice
  5. Post-fermentation Extraction

    1. Maceration after fermentation for further extraction of tannin
  6. Press Wine

    1. Press wine: After maceration is finished, the free run wine is drawn off the skins and the remaining mass is pressed
      • At the start of pressing: this press wine is similar to the free run wine
      • As the pressing continues: the wine becomes deeper in colour and higher in tannin
    2. Press fractions: separated wines from different stages in the pressing
      • Later press fractions may be used to adjust colour and tannin in the final blend

3.2. Whole Bunch Fermentation

  • The aim of this technique: to create an oxgen-free environment for the uncrushed fruit
    • Distinctive fruity aromas is created inside the berry, giving wines made in this way unique qualities
    • Intracellular fermentation: Berries create some alcohol in the cell without involvement of any yeast
  • The vast majority of red wines are made solely with crushed fruit. Yet, some winemakers include whole bunches of uncrushed grapes (entirely or a small percentage) in the fermentation
  • If whole bunches are used, the winemaker must ensure that the grape stems are fully ripe to avoid undesirable bitter taste from unripe stems
  1. Carbonic maceration

    1. Placing only whole, uncrushed bunches into vats that are then filled with CO2 to remove all the oxygen
      • This causes intracellular fermentation to start
      • Once the level of alcohol in the grape reaches 2% the skins start to split and the juice is released
      • Then, the grapes are generally pressed to separate juice from skins
      • Yeast then complete the fermentation off the skins
    2. This method extracts colour but little tannin
      • Resulting wines are soft & full of fruit
      • Distinctive notes of kirsch, banana, bubble gum and cinnamon-like spice
  2. Semi-carbonic maceration

    1. Similar to carbonic maceration, but does not involve filling the vats with CO2
      • Vats are filled with whole bunches and grapes at the bottom of vats are crushed under the weight of the grapes above
      • Some juice is released and ambient yeast start to ferment the juice, creating CO2
      • This CO2 fills the vat and the remaining intact berries undergo carbonic maceration
      • As the intact grapes begin to split and releases their juice the grapes are pressed and yeast complete the fermentation off the skin
      • Alcoholic fermentation continues on the skins and grapes will be progressively broken up using punching down over the course of the first few days
      • An ever-decreasing amount of carbonic maceration takes place until all the grapes are broken up
      • Alcoholic fermentation will continue and may be followed by a post-fermentation maceration
    2. Some notable premium Pinot Noirs are made using this technique
      • This approach can result in a better integration of the aromas from intracellular fermentation with aromas from the grape variety
      • The resuling wine has a fresher fruit character
  3. Whole bunches with crushed fruit

    1. To mix whole bunches with crushed grapes in the fermenting vessel at the start of fermentation
    2. Whole bunches are not blanketed in CO2, but largely submerged by the crushed grapes and kept away from oxygen
      • Intracellular fermentation takes place in these whole bunches
    3. Whole bunches are crushed during the fermentation as the cap is regularly punched down
    4. More ‘carbonic’ characteristics can be achieved by raising the percentage of whole bunches at the start of fermentation, giving the wine a silkier texture and brighter, fresher fruit character

3.3. Maturation Options

  • Oak or no oak: the most important decision for pre-bottling maturation
    • Best wines normally made with higher-quality,more concentrated fruit that can support a greater level of new oak flavours
  • Virtually all red wines undergo MLF
  • More robust flavours and textures of red wine compared to white mean they benefit less from lees contact

3.4. Blending

  • By variety
    • Blending of two or more grape varieties is fairly common in red wine production
    • To enhance or balance the colour, body, tannin, acidity or flavour
  • By press fractions with free run wine
    • To boost the colour, flavour and tannin
  • By maturing vessels
    • To boost complexity by blending wines matured in oak vessels of different ages, sizes and toasting levels
    • For more subtle oak influence, wines matured in oak may be blend with wines matured in stainless steel or concrete vessels
  1. Clarification & Stabilisation

    1. Some form of fining and/or filtration to improve the clarity and stability
    2. However, some winemakers may avoid these processes believing that they harm the wine’s structure
    3. Gradual sedimentation naturally occurs during a long maturation before bottling, improving clarity with out filtration

3.5. Producing High-volume, Inexpensive Red Wines

  • These high-volume, inexpensive wines are normally from warm, sunny and dry areas with black grape varieties like Cabernet Sauvignon, Merlot, Syrah/Shiraz and Grenache/Garnacha
    • Easy to extract colour, flavours and tannin
    • Yet, the distinctive characteristics from these grape varieties can be diminished, leading to rather homogeneous wines
  • Pinot Noir is rarely used as it is hard to grow, prefers cool climate
    • Difficult to extract colour and tannin, thus not suitable for high-volume winemaking
  1. Winemaking Choices

    1. Avoid oxidation: To retain pure, simple primary fruit flavours
    2. Acidification: most common adjustment for grapes grown in warm or hot regions
    3. Fermentation vessel: static and/or rotary vessels
    4. Fermentation temperature: 22°C – 25°C to maximise fresh fruit flavours
    5. Cap management: normally not heavily worked
    6. Yeast: commercial yeast to ensure a quick, reliable fermentation
    7. Post-fermentation maceration: generally avoided due to the constraint on vat space and time, also extra tannin not desirable for these easy drinking style wines
    8. Carbonic/Semi-carbonic maceration: inexpensive wines made from Grenache and basic Beaujolais
    9. Oak maturation: if used, only for a short period, up to a few months
    10. Stabilisation, sterilisation, filtration
    11. SO2 top up to reduce the risk of oxidation

3.6. Producing Premium Red Wines

  1. Cabernet Sauvignon

    1. Thick-skinned: abundant of colour, flavour and tannin
    2. Late ripening: struggle to ripen fully in cool climates, giving wines with astringent tannins and herbaceous flavours
    3. Haut-Médoc in Bordeaux
      • can make long-lived wines with gripp tannins in their youth, with cedar and blackcurrant leaf aromas
      • With age, the tannins soften and the flavours become more expressive
      • Usually blended with Merlot, which ripens earlier, with juicy plum flavours and a smoother texture
    4. Italy: blended with Sagiovese
    5. Spain: blended with Tempranillo
    6. New world
      • Warm temperature and long hours of sunshine result full-bodied wines with ripe black currant, black cherry and smooth tannins
      • Napa Valley in California
      • Coonawarra and Margaret River in Australia
      • Hawke’s Bay in New Zealand
      • Stellenbosch in South Africa
      • Colchagua Valley in Chile
    7. Usually destemmed and crushed to avoid herbaceous and astringent character from stems
    8. Pre-fermentation maceration: to maximise the extraction of colour
    9. Fermentation temperature: 26°C – 30°C 
      1. Warm enough for sufficient extraction
      2. Cool enough to promote fresh fruit flavours
    10. High temperature and extractive cap management techniques generally avoided towards the end of fermentation due to high levels of tannin
    11. Post-fermentation maceration: to encourage gentle extraction of tannin and to soften existing tannins
    12. Oak maturation & bottle ageing: well suited given its structure
      1. Intense flavours, medium to full body and high tannin
      2. Thus, new oak can often be used without overpowering the wine
      3. French oak widely used, with 225-litre barriques most popular
      4. The period of maturation can last from six months to four years
    13. Blending: high tannin and lack of body on its own
      1. Merlot (Bordeaux) which can provide softness and fruit
      2. Shiraz (Australia) for similar reasons
  2. Merlot

    1. Buds & Ripens earlier than Cabernet Sauvignon
    2. Dominant variety in Saint-Émilion and Pomerol
    3. Best quality Merlot wines 
      • International style: Late harvest
        • Intense purple colour
        • Concentrated blackberry and plum
        • Velvety tannin texture
        • Matured in new oak to add toasty flavours
        • Some Bordeaux, South of France, New World
      • Bordelais style: Earlier harvest
        • Medium body and alcohol
        • Higher acidity
        • Fresh red fruit, vegetal and leafy aromas
        • Rarely found outside Bordeaux
    4. Toast, vanilla and clove notes of new oak suit the juicy, plum fruit of Merlot
    5. Merlot is made using very similar techniques to Cabernet Sauvignon
  3. Pinot Noir

    1. Early budding & early ripening with a thin skin: opposite of Cabernet Sauvignon
    2. A very old variety with many clones
    3. Colour and tannin can be tricky to extract
    4. Best grown in cool or moderate climate
    5. Burgundy
      • Entry level wines: very light, marked acidity and a hint of oak
      • Better sites in Côte-d’Or: greater intensity and complexity
    6. Other high-quality regions
      • Baden in Germany
      • Los Carneros and Sonoma in California
      • Martinborough, Marlborough and Central Otago in New Zealand
      • Yarra Valley, Mornington Peninsula and Tasmania in Australia
      • Walker Bay in South Africa
      • Casablanca Valley in Chile
    7. Some winemakers destem and crush
    8. Pre-fermentation maceration: to maximise the extraction of colour
    9. Yet, others include whole bunches in fermentation
      • This enhances red fruit and floral characters
    10. Fermentation temperature: above 30°C 
      • Cooler temperature may be used for ligher, fresher styles
      • Warmer temperatures enable more colour, flavour and tannin to be extracted for longer-aged wines
    11. Post-fermentation maceration: not widely practised
    12. Oak maturation
      • Often matured in oak barrels
      • Due to its delicate flavours, new oak can be too much – second or third-fill barrels are mostly used
      • The period of maturation for premium wines can last from 12 to 24 months
    13. Blending: not usually blended with other variety
      • Blending by different vineyard plots
      • Blending by wines with different treatments in winemaking
    14. Bottle ageing: best wines can develop for many years, gaining flavours of forest floor and mushroom
  4. Syrah/Shiraz

    1. Will not ripen in cool climates, with small grapes that have thick and dark skins
    2. Can produce wines in a range of styles depending on the climate and the winemaking techniques
      • Medium-bodied with pepper and fresh black fruit aromas
      • Full-bodied, smooth with intense and very ripe black fruit aromas and hint of iquorice
    3. Long-ageing potential: intensity of fruit, deep colour and high tannins
    4. Northern Rhône
      • Coolest limit for Syrah production
      • Lesser sites: light wines with simple black fruit and herbaceous flavours
      • Côte-Rôtie & Hermitage: fuller body, berry flavours, hint of pepper, meat and leather after ageing
    5. Languedoc & Roussilon: blended with other black varieties (Grenache, Mourvèdre, Carignan and Cinsault)
    6. Shiraz in Australia
      • Hot regions (Hunder & Barossa Valleys): soft, earthy, spicy style with concentrated black fruit aromas
      • Cooler areas (Great Southern, Geelong and Heathcote): leaner, more peppery style
    7. Other New World regions:
      • Hawke’s Bay in New Zealand
      • Washington State in USA
    8. Warm & hot climates
      • Cap management: vigorously to extract maximum colour, flavour and tannin from ripe or overripe grapes
      • New oak can be complimented to add toasty flavour
    9. Moderate climates (or grapes harvested earlier in warm and hot climates)
      • Gentler cap management
      • Whole bunches in fermentation
    10. Post-fermentation maceration: to extract and smooth tannins
    11. Oak maturation
  5. Grenache/Garnacha

    1. Late-ripening and requires warm or hot climates
    2. High tolerance for drought conditions
    3. Sweet and thin skinned grapes: high alcohol and low acidity
    4. Full bodied with soft tannins and red fruit flavour
    5. Garnacha in Spain
      • Priorat (blended wih Carignan): deeply coloured with high levels of tannin, fresh black fruit and toasty oak
      • Rioja (blended with Tempranillo)
      • Calatayud, Cariñena, Navarra
      • Number of rosé wines from Garnacha
    6. Southern Rhône
      • Châteauneuf-du-Pape: finest example, blended with Syrah and Mourvèdre, producing full bodied, richly textured wines with concentrated spicy red fruit
    7. Languedoc & Roussilon: blended with other black varieties (Syrah, Mourvèdre, Carignan and Cinsault)
    8. Barrosa Valley & McLaren Vale: intensely concentrated, full-bodied styles with high levels of alcohol
    9. Usually destemmed and crushed on arrival at the winery
    10. Pre-fermentation maceration: common practice to maximise the extraction of colour
    11. Some choose to retain a portion of whole bunches to enhance the ripe red fruit flavour of this grape
    12. Fermentation usually done in open top fermenters
    13. Gentle cap management such as punching down used on premium wines 
    14. Post-fermentation maceration: to enhance the tannic structure
    15. However, usually Grenache will be drained off the skins at the end of fermentation
    16. Oak maturation
      1. Usually in large vessels such as foudres made from old oak to avoid overwhelming Grenache’s fruit flavours
    17. Blending: rarely made as varietal wine, more usually blended with other varieties
      1. In hot climates: Grenache may be jammy and high in alcohol
      2. Thus, varieties more tolerant of heat can be used for blending: Carignan, Mourvèdre

3.7. Rosé Winemaking

  1. Direct Pressing

    1. The black grapes are crushed and pressed in the same way as in white wine production
    2. This extracts a little colour
    3. This method often produces the most delicately coloured rosé wines
  2. Short Maceration

    1. The black grapes are crushed and allowed to macerate to extract flavour and colour
    2. The duration of maceration will depend on how much colour and tannin is desired
    3. The free run juice will then be drained off ths skins and fermented at cool temperature, just like white wine
  3. Blending

    1. A small quantity of red wine is added to a white wine
    2. This method is not permitted in EU, except the rosé Champagne
    3. Yet, some fruity, inexpensive New World rosé wines are made this way

 

4. Factors that Affect the Price of Wine

4.1. Production Costs

  1. Grape growing

    1. Vineyard: land itself not cheap
    2. Labour: usually the largest production cost
  2. Winemaking

    1. Equipments
    2. Time needed the wine may need to be kept before release for sale
    3. Storage facilities

4.2. Packaging

Bottles, labels, capsules, closures and cartons

4.3. Transport, Distribution & Sales

Very complex and highly regulated

4.4. Taxes

Nearly every government in the world taxes alcoholic beverages and the level of taxes vary significantly

4.5. Retailers

Restaurants and shops need their profit margins

4.6. Market Forces

Supply and Demand

4.7. Types of Wine Producers

  1. Co-operatives

    1. Wine businesses owned by their members, typically grape growers
    2. Good for growers as they have a guaranteed buyer
    3. Can be challenging for winemakers as they cannot control the quality of grapes provided by their employers
    4. Very common in Europe
  2. Merchants (Négociant)

    1. They buy grapes, juice or wine from either growers or co-operatives
    2. In theory, they may have greater control over the source material as they can reject grapes that are not up to standard
    3. Many of large wine brands are made this way
    4. Common throughout the world, especially outside Europe
  3. Estates (Domaine)

    1. They make wine only from the grapes that they grow
    2. Typically, they produce wine on a relatively small scale
    3. Greatest amount of control throughout the process, thus responsible for the best wines
    4. Yet, they can have fewer blending options as they only use what they grow and this could be problematic in poor vintages due to weather conditions

 

5. Wine and the Law

 5.1. Food Safety

  1. SO2

    1. Universally used in winemaking
    2. If consumed in very high doses it can be toxic
    3. In most countries the word ‘contains sulfites’ must appear on the label

5.2. Label Integrity

  1. Geographical Indications (GIs)

    1. A product’s region or place of origin
      • Can be very large and cover an entire region (e.g. Bordeaux)
      • Can be very small and covering no more than a single vineyard (e.g. La Romanée in Burgundy)
      • Thus, very tightly controlled to ensure a wine is genuinely the product of the grapes grown in the location stated on the label
      • WTO (World Trade Organisation) has developed a system that is widely used now
  2. European Union

    1. Protected Designation of Origin (PDO)
      • Smaller area with more tightly defined regulations
      • Appellation d’origine contrôlée (AOC or AC) in French
      • Local laws will also specify what grape varieties can be grown, and what growing and winemaking techniques can be used
      • Promoting quality and preventing fraud by creating the unique identity
      • 100% of the grapes must come from the stated region of origin
      • Many PDO wines do not state the grape variety on the label
    2. Protected Geographical Indication (PGI)
      • Larger and have fewer regulations
      • Quality can vary from exceptional to inexpensive high-volume wines
      • Indication géographique protégée (IGP) in French or more traditionally Vin de Pays
      • Less restrictive than PDO
      • Grape variety is usually stated on the label
  3. Non-EU countries

    1. No local laws to define and limit what grape varieties can be planted
    2. The legal terms rarely appear on the label
  4. Legally Defined Quality & Style Indications

    1. Evolved in developed in the EU and defined by local laws to indicate both quality and style

5.3. Safe Consumption

  • Minimum Legal Age for both the purchase and consumption
  • Legal Limit on the amount of alcohol in the blood when driving (mg/ml)
  • Sensible drinking guidelines
  • Limitations on advertising and marketing of alcoholic beverages

1 Comment

  1. Jooh
    15 Feb 2017

    So much to learn!

    Reply

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