Wine Course 5
Sparkling Wine
Wine Course 5 Sparkling Wine
Sparking wine effervesces either as the result of carbon dioxide, produced by fermentation, being trapped in the bottle or as a result of carbon dioxide being injected into still wine.
There are four principal methods of making sparkling wine: the Traditional Method; the Tank Method; the Transfer method and the Injection method.
1) The Traditional Method
In this method there is a primary fermentation to produce a dry wine which is then bottled. When the wine is bottled yeast and sugar are added to the dry wine before it is sealed. A second fermentation then takes place in the same bottle to trap carbon dioxide gas. Any sediment which has formed is removed by a process of riddling or gently shaking the bottle (remuage) to settle the particles in the neck of the sealed bottle. The neck of the bottle is then frozen; the sediment is disgorged and the bottle resealed. Before resealing with a wired cork, the bottle is topped up with a similar wine, and then a sugar based syrup (liqueur d’expedition) is added according to style. Riddling by hand and disgorgement have, largely, been replaced by automated methods..Some expensive and high quality Champagnes are, however, still riddled and disgorged by hand.
The Traditional Method is used to make top quality sparkling wines such as Champagne, Cava and premium Sekt.
2) The Tank Method
The wine is made in a pressure tank or “cuve close” , the second fermentation produces a sparkling wine which is then filtered and bottled under pressure and at a low temperature. This process is used for bulk sparkling wine production. This method is sometimes named the Charmat method , after Eugene Charmat who first used the process. Most Sekt, Prosecco and Asti (Spumante) is produced by this method. Some commentators believe that the tank method is superior to the traditional method when making sweet sparkling wine.
3) Transfer Method
This is a cross between the traditional and tank methods; the second fermentation takes place in the bottle but then it is disgorged to a tank under pressure and at a low temperature. The wine is then filtered to remove the sediment and rebottled under pressure. Many good quality wines are made by this method especially in Germany, Australia and the USA.
4) The Injection Method or Carbonation
In this method bulk still wine which has been chilled is injected under pressure with carbon dioxide. Once the bottle is opened the wine quickly loses its sparkle, but modern carbonation techniques are improving the quality and longevity of the bubble effect.
5) Champagne
The traditional method was invented in France. In the 17th century the monk Dom Perignon is reputed to have invented the method of sealing the bubbles in glass bottles, which were now strong enough to withstand the pressure. He also invented the method of blending wines to create an individual style. In the 19th century, la veuve Clicquot ( the widow Clicquot) invented the methods of riddling and disgorging the sediment. From then on, the traditional method was finalised.
The names Champagne and “Mêthode Champenoise” are legally protected. Champagne is regarded is the finest sparkling wine. White champagne is most usually made from a blend of wines made from white and black grapes: Chardonnay, Pinot Noir (black) and Pinot Meunier(black). Blanc de Blancs style is made exclusively from white Chardonnay grapes .Rosé champagne is made from a blend of white and red wine.
6) Some questions
What gas produces the bubbles in Sparkling wine?
What is the most famous sparkling wine?
Who invented remuage or riddling?
What is the injection method of making sparkling wine?
Who first used the tank method to make sparkling wine?
What is Blanc de Blancs?
In what century did Dom Perignon make sparkling wine?
How is sediment removed from wine produced by the transfer method?
By which method is premium Sekt made?
Name another sparkling wine made by the traditional method other than Champagne?
Sunday 22 August 2010
wine course 4
Wine Course 4
Light Wine Making Adjustments and Bottling
Wine Course 4 - Light Wine Making Adjustments and Bottling
There are many adjustments and technical issues to be considered in the production of light wine, and these are discussed below.
1) Malo-lactic Conversion
Many wines, especially reds, contain too much malic acid which makes the wines taste tart. Apples contain this acid which is why they often taste sharp. To reduce the malic acid concentration, wine makers encourage the growth of bacteria, such as Lactobacillus, which convert this acid to softer tasting lactic acid. This adjustment is often called secondary fermentation and takes place in the fermentation vat before the wine is drawn off for maturation.
2) Residual sugar
The residual sugar left in the wine after fermentation determines the sweetness of the wine; either dry, medium, medium sweet or sweet:
Dry wine up to 9 grams per litre of sugar
Medium up to 18 grams per litre
Medium Sweet up to 45 grams per litre
Sweet no less than 45 grams per litre
Naturally sweet wines are produced when the fermenting must is unable to convert all the sugar into alcohol. To prevent the alcohol level from becoming too high, very sweet grapes are used in the original must; and this high level of sweetness inhibits the growth of yeast. Grapes exposed to “noble rot” contain a natural fungicide which, also, inhibits yeast growth. Cooling the wine then stops the fermentation.
3) Alcohol
Light wines are fermented to between 8% and 15% alcohol by volume depending on style. Most wine is fermented to around 12% to 14%. The level of alcohol is controlled by the amount of sugar available for fermentation, the yeasts used, the temperature and the length of time the wine is allowed to ferment. If a wine achieves a 15% level of alcohol fermentation stops.
Modern techniques can stop fermentation and alcohol production by the addition of sulphur dioxide to kill the yeast, filtering out the yeast or increasing the pressure of carbon dioxide. This can result in an unstable wine which might start to re-ferment.
4) Yeasts
Traditional fermentation used natural yeasts found on the grapes, in the air and on the surfaces of the vineyard to ferment the must.
Modern methods use yeasts cultured in the laboratory and sold as a freeze dried product or as a living culture.
Whilst cultured yeasts enable the wine maker to control fermentation better, the use of standardised yeast cultures has lead to loss of individuality of taste and standardised wines which taste the same across the world. Some winemakers are using a mixture of traditional and modern techniques.
5) Must Adjustment
Before fermentation starts, the grape must is protected by the addition sulphur dioxide which acts as a disinfectant and anti-oxidant. It is added in the form of potassium sulphite or potassium meta-bisulphite powder.
In vintages where the weather has been less than kind, the grapes may not be balanced for acids and sugars. The wine must is then adjusted by adding or removing acid from the must to control acidity Adding sugar or rectified concentrated grape must improves the sweetness of the grapes. Biochemical intervention must be controlled carefully, and in the EU is controlled by rules. There is really no substitute for using high quality grapes.
6) Racking
After fermentation is complete wines are racked to allow dead yeasts to fall to the bottom of the vat as sediment or lees. This helps to clear the wine before it is drawn off the lees for subsequent maturation. Several racking operations may be conducted throughout the maturation process.
7) Fining
Fining is used to remove haze producing colloids, in the wine, and help clarify it. The fining agents used include: egg white, gelatine, bentonite and isinglass gelatine.
8) Filtration
Filtration is not usually used for traditionally made wines, which often throw natural sediments whilst they age in the bottle.
Modern wine making techniques use coarse filtration to remove particles to clarify the wine. Membrane filters are sometimes used to remove micro-organisms and sterilise the wine.
It is a controversial subject when filtration is used for traditionally produced wines, as some commentators believe it ruins the wine.
9) Sweetening
Some commercially produced light wine is sweetened before with bottling with rectified concentrated grape must. In the European Union this is strictly controlled.
10) Bottling and other packaging
Most wine is sold in glass bottles. Glass is the best medium for storing wine when it needs to be aged before drinking. All top quality wine is bottled.
There is increasing use of “bag in the box”, cardboard “tetrapack” and plastic bottles. These add to the convenience of storing and serving the wine quickly. The wine deteriorates more quickly in this type of package which is meant for commercially produced wine. The shelf life of these products is limited and should be noted before purchase.
Whatever the form of bottling or packaging, all wine is preserved with sulphur dioxide before packaging and all containers must be completely clean and aseptic before they are filled.
11) Seals
The traditional method of sealing bottles was to use seals made of natural cork. However, the problem of cork taint, where a fungal infection caused a taste of mould to taint the wine, has converted some wine makers to use “technical corks”, plastic corks or screw caps to eliminate the cause of cork taint. It is estimated that 5% of wines sealed with natural cork are subject to cork taint.
Artificial seals also reduce the ingress of oxygen into the bottle. Screw caps are increasingly seen as being an ideal solution but they can easily get damaged in transit or on the supermarket shelf.
Natural cork is still being used to seal wines meant for ageing; as they allow very small amounts of oxygen to penetrate the wine to help it mature. This point is, however, hotly debated. Top quality wines are sealed with very long corks.
Natural cork suppliers are “fighting back” by improving cork preparation techniques to eliminate the cork taint problem.
The use of seals is hotly debated as this is where the wine actually meets the consumer after a long process. The pulling of a cork remains part of the mystique of wine consumption. Many quality wines producers will no doubt retain natural corks.
12) Some Questions
What happens to fermentation when the alcohol level reaches 15% by volume?
What types of yeast are used for fermentation by the traditional method?
What type of filter is used to remove particles?
What is egg white used for?
What does cork taint smell of?
What is used to sweeten some commercially produced wine?
What type of container is used for wines meant for ageing?
Why are wines racked during maturation?
What is potassium sulphite used for?
Why should a wine bottle sealed with a screw cap be examined before purchase?
What prevents a very sweet grape must from fermenting to too high a level of alcohol?
Light Wine Making Adjustments and Bottling
Wine Course 4 - Light Wine Making Adjustments and Bottling
There are many adjustments and technical issues to be considered in the production of light wine, and these are discussed below.
1) Malo-lactic Conversion
Many wines, especially reds, contain too much malic acid which makes the wines taste tart. Apples contain this acid which is why they often taste sharp. To reduce the malic acid concentration, wine makers encourage the growth of bacteria, such as Lactobacillus, which convert this acid to softer tasting lactic acid. This adjustment is often called secondary fermentation and takes place in the fermentation vat before the wine is drawn off for maturation.
2) Residual sugar
The residual sugar left in the wine after fermentation determines the sweetness of the wine; either dry, medium, medium sweet or sweet:
Dry wine up to 9 grams per litre of sugar
Medium up to 18 grams per litre
Medium Sweet up to 45 grams per litre
Sweet no less than 45 grams per litre
Naturally sweet wines are produced when the fermenting must is unable to convert all the sugar into alcohol. To prevent the alcohol level from becoming too high, very sweet grapes are used in the original must; and this high level of sweetness inhibits the growth of yeast. Grapes exposed to “noble rot” contain a natural fungicide which, also, inhibits yeast growth. Cooling the wine then stops the fermentation.
3) Alcohol
Light wines are fermented to between 8% and 15% alcohol by volume depending on style. Most wine is fermented to around 12% to 14%. The level of alcohol is controlled by the amount of sugar available for fermentation, the yeasts used, the temperature and the length of time the wine is allowed to ferment. If a wine achieves a 15% level of alcohol fermentation stops.
Modern techniques can stop fermentation and alcohol production by the addition of sulphur dioxide to kill the yeast, filtering out the yeast or increasing the pressure of carbon dioxide. This can result in an unstable wine which might start to re-ferment.
4) Yeasts
Traditional fermentation used natural yeasts found on the grapes, in the air and on the surfaces of the vineyard to ferment the must.
Modern methods use yeasts cultured in the laboratory and sold as a freeze dried product or as a living culture.
Whilst cultured yeasts enable the wine maker to control fermentation better, the use of standardised yeast cultures has lead to loss of individuality of taste and standardised wines which taste the same across the world. Some winemakers are using a mixture of traditional and modern techniques.
5) Must Adjustment
Before fermentation starts, the grape must is protected by the addition sulphur dioxide which acts as a disinfectant and anti-oxidant. It is added in the form of potassium sulphite or potassium meta-bisulphite powder.
In vintages where the weather has been less than kind, the grapes may not be balanced for acids and sugars. The wine must is then adjusted by adding or removing acid from the must to control acidity Adding sugar or rectified concentrated grape must improves the sweetness of the grapes. Biochemical intervention must be controlled carefully, and in the EU is controlled by rules. There is really no substitute for using high quality grapes.
6) Racking
After fermentation is complete wines are racked to allow dead yeasts to fall to the bottom of the vat as sediment or lees. This helps to clear the wine before it is drawn off the lees for subsequent maturation. Several racking operations may be conducted throughout the maturation process.
7) Fining
Fining is used to remove haze producing colloids, in the wine, and help clarify it. The fining agents used include: egg white, gelatine, bentonite and isinglass gelatine.
8) Filtration
Filtration is not usually used for traditionally made wines, which often throw natural sediments whilst they age in the bottle.
Modern wine making techniques use coarse filtration to remove particles to clarify the wine. Membrane filters are sometimes used to remove micro-organisms and sterilise the wine.
It is a controversial subject when filtration is used for traditionally produced wines, as some commentators believe it ruins the wine.
9) Sweetening
Some commercially produced light wine is sweetened before with bottling with rectified concentrated grape must. In the European Union this is strictly controlled.
10) Bottling and other packaging
Most wine is sold in glass bottles. Glass is the best medium for storing wine when it needs to be aged before drinking. All top quality wine is bottled.
There is increasing use of “bag in the box”, cardboard “tetrapack” and plastic bottles. These add to the convenience of storing and serving the wine quickly. The wine deteriorates more quickly in this type of package which is meant for commercially produced wine. The shelf life of these products is limited and should be noted before purchase.
Whatever the form of bottling or packaging, all wine is preserved with sulphur dioxide before packaging and all containers must be completely clean and aseptic before they are filled.
11) Seals
The traditional method of sealing bottles was to use seals made of natural cork. However, the problem of cork taint, where a fungal infection caused a taste of mould to taint the wine, has converted some wine makers to use “technical corks”, plastic corks or screw caps to eliminate the cause of cork taint. It is estimated that 5% of wines sealed with natural cork are subject to cork taint.
Artificial seals also reduce the ingress of oxygen into the bottle. Screw caps are increasingly seen as being an ideal solution but they can easily get damaged in transit or on the supermarket shelf.
Natural cork is still being used to seal wines meant for ageing; as they allow very small amounts of oxygen to penetrate the wine to help it mature. This point is, however, hotly debated. Top quality wines are sealed with very long corks.
Natural cork suppliers are “fighting back” by improving cork preparation techniques to eliminate the cork taint problem.
The use of seals is hotly debated as this is where the wine actually meets the consumer after a long process. The pulling of a cork remains part of the mystique of wine consumption. Many quality wines producers will no doubt retain natural corks.
12) Some Questions
What happens to fermentation when the alcohol level reaches 15% by volume?
What types of yeast are used for fermentation by the traditional method?
What type of filter is used to remove particles?
What is egg white used for?
What does cork taint smell of?
What is used to sweeten some commercially produced wine?
What type of container is used for wines meant for ageing?
Why are wines racked during maturation?
What is potassium sulphite used for?
Why should a wine bottle sealed with a screw cap be examined before purchase?
What prevents a very sweet grape must from fermenting to too high a level of alcohol?
wine course 3
Winecourse3
Light Wine making
Winecourse3 – Light Wine making
Winemaking and or vinification is equally as important as the quality of the grapes used to make good wine. In the mid 19th century, Louis Pasteur researched the fermentation process, which produces both wine and beer, and discovered that yeast, especially Saccharomyces Cerevisae, is responsible for the process. Since his discoveries winemaking has become an increasingly science and technological based procedure. Some wine producers now make wine on an industrial scale. Pasteur also researched the role of oxygen in winemaking.
1) Fermentation
In the fermentation process, yeast converts the sugars in the grape juice to alcohol and carbon dioxide. This form of fermentation, however, must occur anaerobically or in the absence of oxy gen. If yeasts are supplied with unlimited supplies of oxygen, the sugars in the grape must are converted to just water and carbon dioxide. Yeasts “prefer” to reproduce in the presence of oxygen as they can derive more energy from the sugar. The role of oxygen is, therefore, very important in wine making. For light wines, the carbon dioxide is allowed to vent into to the atmosphere.
2) Oxygen
Oxygen must be controlled at all stages in the fermentation of wine. It can destroy fruit flavours or oxidise alcohol to undesirable chemicals such as acetaldehyde or acetic acid.
Small quantities of oxygen are, however, involved in the ageing process of top quality wines. Some fortified wines such as Sherry and Madeira are produced in a deliberately oxidised process to give them their distinctive style; so if a light wine smells of Sherry or Madeira it has probably been oxidised and is faulty.
Traditional methods of wine making did not concentrate on the exclusion of oxygen. Modern methods use anaerobic techniques to exclude oxygen from most of the stages of winemaking, by use of anti-oxidants, carbon dioxide or nitrogen etc., to exclude oxygen and produce fruitier wines.
3) Light red wine production
Red wine is made predominantly from black grapes. The pigment which gives red wine its colour is contained only in the skin of the grape and not in the juice which is clear.
The grapes are de-stalked and crushed, usually, by machinery. The crushing produces the grape must and then the grape skins and must are transferred to a fermentation vat.
The must is fermented, usually, at between 20 and 32 degrees celcius.
Modern techniques use stainless steel vats to better control temperature and exclude oxygen. Traditional methods use wooden (oak) vats which allow oxygen to penetrate the must but add the tannins and oak flavour to the wine. Other types of vat are also used such as glass lined cement containers.
The period of fermentation affects the style of the wine: lighter style wines such as Beaujolais will ferment for about five days, heavier styles such as Barolo for about 10 days or longer to extract more tannin and red pigment.
When the fermentation is complete the wine is run off (“free run”) to a fresh vat. The skins are then drawn off and pressed to extract a pressed wine which is rich in pigments and tannin. This “press wine” is then blended with the “free run “wine according to the desired style.
The finished wine is then drawn off to mature in stainless steel vats or oak barrels depending on style.
Adjustments to the wine must may be made before fermentation and the wine will be racked to allow sediments to fall or fined to remove haze before maturation.
4) Light white wine production
White wine is usually made from white grapes but the juice of black grapes is clear and if their skins are removed from the must a white wine will result.
The grapes are crushed and pressed and the juice is fed to a vat without the skins. Modern methods use stainless steel vats but wooden vats are sometimes used as per red wine production.
The must is fermented at a lower temperature, usually, between 10 to 18 degrees celcius. The fermentation period is usually longer than for red wine at around 14 to 28 days. The lower temperature preserves the more delicate odours and flavours of the white wine but, also, increases the time needed for fermentation.
The finished wine is then run off to mature, either in stainless steel vats or wooden barrels according to style.
Once again adjustments may be made to the must before fermentation and the wine may be racked and fined before maturation.
5) Light Rosé Wine production
Rosé wine is made in a similar process to red wine. Black grapes are used, but some white grapes could be added to the must. The grapes are crushed and are fermented with their skins for a short period of 12 to 48 hours. The fermenting must is then run off to another vat to complete fermentation, but at a lower temperature than red wine. Press wine is not added to the final wine. The result is a wine with less colour and pigmentation than red wine.
Some bulk and cheap Rosé wine is made by blending red and white wine.
6) Maturation
Wines are matured for varying lengths of time in stainless steel vats, stainless steel barrels or oak barrels before bottling. The maturation process rests the wine and allows flavours to develop.
Oxygen is excluded from the process to prevent it from adversely affecting the wine. This means that wine matured in wooden barrels needs to be topped up to replace wine lost by evaporation. Wooden barrels allow very small amounts of air to seep into the wine but this is part of the maturation process.
Top quality wines are matured in oak barrels which impart extra flavour and tannin to the maturing product. Some commercial producers mimic this process by adding oak chips or oak staves.
7) Some Questions
What temperature is white wine fermented at?
Why is better quality wine matured in oak barrels?
What type of grape is used to make good quality Rosé wine.
Why can white wine be made of black grapes?
Where does the pigment which gives red wine its colour come from?
What temperature is red wine fermented at?
Why is white wine fermented at a lower temperature than red?
Name a component of “press” wine.
Why is a light wine which smells of sherry or Madeira probably faulty?
What happens if yeast is allowed to have un-limited supplies of oxygen during the fermentation process?
Name one of the undesirable chemicals produced when wine is exposed to too much oxygen.
What is the principal species of yeast used to ferment the grape must?
Light Wine making
Winecourse3 – Light Wine making
Winemaking and or vinification is equally as important as the quality of the grapes used to make good wine. In the mid 19th century, Louis Pasteur researched the fermentation process, which produces both wine and beer, and discovered that yeast, especially Saccharomyces Cerevisae, is responsible for the process. Since his discoveries winemaking has become an increasingly science and technological based procedure. Some wine producers now make wine on an industrial scale. Pasteur also researched the role of oxygen in winemaking.
1) Fermentation
In the fermentation process, yeast converts the sugars in the grape juice to alcohol and carbon dioxide. This form of fermentation, however, must occur anaerobically or in the absence of oxy gen. If yeasts are supplied with unlimited supplies of oxygen, the sugars in the grape must are converted to just water and carbon dioxide. Yeasts “prefer” to reproduce in the presence of oxygen as they can derive more energy from the sugar. The role of oxygen is, therefore, very important in wine making. For light wines, the carbon dioxide is allowed to vent into to the atmosphere.
2) Oxygen
Oxygen must be controlled at all stages in the fermentation of wine. It can destroy fruit flavours or oxidise alcohol to undesirable chemicals such as acetaldehyde or acetic acid.
Small quantities of oxygen are, however, involved in the ageing process of top quality wines. Some fortified wines such as Sherry and Madeira are produced in a deliberately oxidised process to give them their distinctive style; so if a light wine smells of Sherry or Madeira it has probably been oxidised and is faulty.
Traditional methods of wine making did not concentrate on the exclusion of oxygen. Modern methods use anaerobic techniques to exclude oxygen from most of the stages of winemaking, by use of anti-oxidants, carbon dioxide or nitrogen etc., to exclude oxygen and produce fruitier wines.
3) Light red wine production
Red wine is made predominantly from black grapes. The pigment which gives red wine its colour is contained only in the skin of the grape and not in the juice which is clear.
The grapes are de-stalked and crushed, usually, by machinery. The crushing produces the grape must and then the grape skins and must are transferred to a fermentation vat.
The must is fermented, usually, at between 20 and 32 degrees celcius.
Modern techniques use stainless steel vats to better control temperature and exclude oxygen. Traditional methods use wooden (oak) vats which allow oxygen to penetrate the must but add the tannins and oak flavour to the wine. Other types of vat are also used such as glass lined cement containers.
The period of fermentation affects the style of the wine: lighter style wines such as Beaujolais will ferment for about five days, heavier styles such as Barolo for about 10 days or longer to extract more tannin and red pigment.
When the fermentation is complete the wine is run off (“free run”) to a fresh vat. The skins are then drawn off and pressed to extract a pressed wine which is rich in pigments and tannin. This “press wine” is then blended with the “free run “wine according to the desired style.
The finished wine is then drawn off to mature in stainless steel vats or oak barrels depending on style.
Adjustments to the wine must may be made before fermentation and the wine will be racked to allow sediments to fall or fined to remove haze before maturation.
4) Light white wine production
White wine is usually made from white grapes but the juice of black grapes is clear and if their skins are removed from the must a white wine will result.
The grapes are crushed and pressed and the juice is fed to a vat without the skins. Modern methods use stainless steel vats but wooden vats are sometimes used as per red wine production.
The must is fermented at a lower temperature, usually, between 10 to 18 degrees celcius. The fermentation period is usually longer than for red wine at around 14 to 28 days. The lower temperature preserves the more delicate odours and flavours of the white wine but, also, increases the time needed for fermentation.
The finished wine is then run off to mature, either in stainless steel vats or wooden barrels according to style.
Once again adjustments may be made to the must before fermentation and the wine may be racked and fined before maturation.
5) Light Rosé Wine production
Rosé wine is made in a similar process to red wine. Black grapes are used, but some white grapes could be added to the must. The grapes are crushed and are fermented with their skins for a short period of 12 to 48 hours. The fermenting must is then run off to another vat to complete fermentation, but at a lower temperature than red wine. Press wine is not added to the final wine. The result is a wine with less colour and pigmentation than red wine.
Some bulk and cheap Rosé wine is made by blending red and white wine.
6) Maturation
Wines are matured for varying lengths of time in stainless steel vats, stainless steel barrels or oak barrels before bottling. The maturation process rests the wine and allows flavours to develop.
Oxygen is excluded from the process to prevent it from adversely affecting the wine. This means that wine matured in wooden barrels needs to be topped up to replace wine lost by evaporation. Wooden barrels allow very small amounts of air to seep into the wine but this is part of the maturation process.
Top quality wines are matured in oak barrels which impart extra flavour and tannin to the maturing product. Some commercial producers mimic this process by adding oak chips or oak staves.
7) Some Questions
What temperature is white wine fermented at?
Why is better quality wine matured in oak barrels?
What type of grape is used to make good quality Rosé wine.
Why can white wine be made of black grapes?
Where does the pigment which gives red wine its colour come from?
What temperature is red wine fermented at?
Why is white wine fermented at a lower temperature than red?
Name a component of “press” wine.
Why is a light wine which smells of sherry or Madeira probably faulty?
What happens if yeast is allowed to have un-limited supplies of oxygen during the fermentation process?
Name one of the undesirable chemicals produced when wine is exposed to too much oxygen.
What is the principal species of yeast used to ferment the grape must?
wine course 2
Wine Course 2
The Vineyard
Wine Course 2 – The Vineyard
Like all form s of agriculture, the growing of vines is influenced by the climate, the weather, the soil and the type of grape grown. It is also influenced by the method of growing the vines and the control of pests and vine diseases. The object of viticulture is to produce the best quality grapes from the available soil. These grapes should be well balanced between the sugars, acids and tannins to produce the style of wine desired. In modern times, grape production has been increasingly subjected to science based technology and some producers are now growing grapes on an industrial scale.
1) The Type of Grapes
Most quality wine is produced from the Vitis Vinifera species which originated in Europe and which dominates commercial wine production. There are thousands of varieties some of which have become better known than others. Famous red wine varieties include Merlot, Cabernet Sauvignon, Pinot Noir, Zinfandel and Shiraz (Syrah). Well known white wine varieties include, Sauvignon Blanc, Chardonnay, Pinot Grigio and Viognier. The variety of grapes grown influences the style and taste of the wine. In Europe, there is a tradition of matching grape varieties to the soil, weather and climate and this is reflected in quality control rules.
2) Soil
The soil plays a major role in agriculture; grape vines like to thrive in poor soils which are well drained. In a poor well drained soil the vine roots are encouraged to penetrate deeply to obtain both water and mineral nutrients. Poor soils reduce the crop yield which is associated with the production of finer quality wines. Richer soils produce higher yields and this is generally associated with lower quality wine. Much research has been made to into the concept of yield versus quality and there is now a modern emphasis on producing high quality grapes from higher yields. It is not only the soil which affect yield but also growing techniques.
The soil is often associated with the style of wine so, for instance, Champagne grapes grow better in chalky soils.
3) Climate
Climate is different to weather. Climate can be defined as the weather conditions averaged over a long period of time. Climate is influenced by latitude and altitude. In general, vines grow best between latitudes 30 and 50 degrees north or south of the equator. Outside of these latitudes the local conditions or micro-climate may allow viticulture. For example, closer to the equator vines can be grown at higher altitudes where the climate is cooler.
Winter should be cold enough to restrict the growth of the vines to rest them. It should produce frosts severe enough to kill insect pests and diseases but not so sever e as to kill the vine itself. There should be sufficient rain to replenish soil moisture.
Spring should be mild to encourage the growth and budding of the vine. There should be sufficient rainfall to replenish the soil’s moisture and water reserves.
The late spring or early summer should be warm to promote the flowering of the vine.
A hot and sunny summer is then needed to promote the development of the grape berry. Light rain is required to swell the growing grape. Sunny conditions are needed in late summer to start the ripening process.
Autumn needs to be sunny and dry to complete the ripening of the grapes.
4) Weather
Local weather conditions can either encourage the good growth of the vines or adversely affect it. Bad weather can either destroy the vines or reduce the size of the crop.
Heavy frost in spring can destroy roots and prevent the budding of the vine.
Hail in late spring and summer can damage young shoots and flowers and in late summer it can damage the developing fruits.
Heavy or prolonged rain in summer can swell the grapes too much and dilute the sugars, flavours and acids in the berries. Heavy or prolonged rain also encourages fungal and mould disease s and slows down late summer ripening.
In autumn, heavy rain delays the ripening of the grapes or delays the harvest. A damp atmosphere also encourages fungal rot
Strong winds can damage the vines when they are flowering or prevent pollination.
It should be noted that the quality of the vintage of a wine is controlled by the weather not the climate. Good weather in all seasons improves the vintage and its wine but bad weather can ruin the quality of the grapes leading to inferior quality wine.
5) Viticulture
The growing methods in the vineyard also have a considerable influence on the quality of the grapes produced. The growing conditions of the grapes are vital to the health of the vine, the quality of the grapes and the control of diseases and pests.
Climate change is now beginning to affect growing conditions in some regions. In Australia drought has lead to changes and advances in irrigation techniques. In Europe, Spain has been affected by drought, in the La Mancha region, and this has lead to changes in the quality control rules to allow irrigation. Climate change may also affect which grapes can be best grown in a region and may prompt further changes to viticulture and changes to the rules in Europe.
Rootstocks
Whilst the actual grapes are produced from the Vitis Vinifera species, the shoots of this vine are grafted onto the roots of American species of vines including: Vitis Berlandieri, Vitis Riparia and Vitis Rupestris,. American rootstocks are resistant to the insect louse Phylloxera Vastatrix which infests vine roots. This louse has spread throughout all vine growing regions of the world. In the late 19th century, this louse almost destroyed viticulture in France and other European countries. Virtually all vines grown throughout the world are European vines grafted onto American rootstocks and this includes the USA. Rootstocks are selected to suit local climate and soil conditions.
Vine Training and Pruning
Vine training and pruning are essential to maintain the origin and health of the grapes. Because European grapes are grafted onto American rootstocks, any shoots produced by the rootstock above the ground must be pruned away to prevent cross-pollination of the grapes and hybridisation. Equally, the canes and shoots of the European vine variety must be prevented from taking root as they are not resistant to the Phylloxera louse and the vines could be destroyed.
Vines are trained in a way which suits the local vineyard conditions, climate and soil. There are two main ways of training the vines:
Cane training where the main horizontal cane is cut off, in winter, to be replaced by a spare cane. Cane trained vines are trellised on wires supported by a frame.
Spur training as often seen on Bush vines. The main canes are not pruned back in the winter. Bush vines are either left un-supported or just supported by a pole. Other forms of spur trained vines are supported on wires and trellises.
There are numerous variations of both types of training and in some European Countries there are rules governing the training methods used.
Vines can be trellised high to avoid ground frosts or trained low to benefit, at night, from heat stored in stones in the soil.
Vine growth is also influenced by the distance between rows of vines and their orientation either to attract sunshine or avoid dampness etc.
Pruning and canopy management also affects the quality of the grapes and the yield, and is adapted to local growing conditions.
The Vineyard year
In winter the vines are allowed to rest. Pruning is used to train the vines and damaged trellises are repaired. The soil is fertilised if necessary. Any grafting is performed in late winter or early spring when the vines begin new growth.
In spring the ground around the vines is ploughed or hoed to aerate the soil. Spraying against pests and disease is started depending on rules. New vines are planted. Vine training and pruning is continued.
In summer, pest and disease control spraying continues according to rules and standards. The canopy is managed by pruning to ensure that vine growth is concentrated on the production of ripe grapes rather than excess leaf cover.
In autumn, the vintage or wine picking takes place. Vines are either hand picked or picked by machine depending on commercial and quality considerations. Some vineyards do not lend themselves to mechanisation because of geography or the spacing of the rows of vines.
Vineyard location
Vineyards need to be located on soil which is conducive to viticulture. The best wines are usually produced from vineyards located on limestone, chalk, gravel, schist, granite or volcanic based soils.
From a weather and climate point of view, the best location for a vineyard is on a slope for good drainage and facing the sun to attract light and heat.
6) Wine pests and Diseases and their Control
Wine pests and diseases create serious problems for the wine grower and must be controlled for economic and quality reasons.
Phylloxera Vastatrix or the Vine louse
This aphid is the most serious vineyard pest and it can only be controlled by using American rootstocks as described before.
Other Insects pests
Other insect pests, such as the grape berry moth, are controlled using insecticides when they become a problem. Organic growers, who are opposed to the use of pesticides, encourage natural insect predators such as ladybirds or predatory wasps.
Downy Mildew
This is caused by the Peronospera mould which thrives in damp conditions and can destroy leaves and grapes. It can be controlled by spraying with either Bordeaux mixture which is a mixture of copper sulphate, lime and water or Copper based sprays. Improved ventilation of the vines helps to prevent the damp conditions which encourage the mould.
Powdery Mildew
Powdery Mildew or Oidium is caused by a fungus which grows in both humid and dry conditions it can affect both the leaves and the grapes. Even a mild case can affect the photosynthesis in the plant leaves. It is controlled by sulphur or fungicides.
Grey Rot
This is caused by the Botrytis Cinerea, this fungus attacks the vine in wet or humid conditions but usually in autumn when the grapes start to ripen. Grey mould covers the leaves and grapes especially white varieties. Bunches of grapes with grey rot can give an unpleasant taste to the wine.
For certain styles of sweet wine, such as Sauternes or Monbazillac and the sweet wines of Germany, grey rot is encouraged, it is then called noble rot. The white grapes are allowed to develop the rot which dries out the grapes and increases the concentration of sugar to make the high quality dessert wines of these regions. Any unpleasant taste is masked by the sweetness of the wine.
7) General Considerations
The climate, weather, grape type, vineyard techniques and pest and disease management are all subjects which can fill many books. In the final analysis, all of these factors combine together to affect the quality of our vines and ultimately our wine.
8) Some questions
What direction is it best for a vineyard to face?
What causes powdery mildew?
Between what latitudes are the wine growing regions mainly located?
Name one type of vine training?
What is the definition of climate?
What is the name of a well known red wine grape?
What is the most important insect pest in the vineyard?
Why are European vines grafted onto American rootstocks?
Name a wine which is produced by grapes exposed to Noble Rot?
What can affect the yield of grapes?
Which soil is regarded as best for growing grapes?
What controls the quality of the vintage the weather or the climate?
In what season are vines left to rest?
In what season does the vintage take place?
What affect does strong wind have on the vine?
Why would vines be trellised high above the ground?
What is the name of a well known white grape?
What components of the grape should be well balanced?
The Vineyard
Wine Course 2 – The Vineyard
Like all form s of agriculture, the growing of vines is influenced by the climate, the weather, the soil and the type of grape grown. It is also influenced by the method of growing the vines and the control of pests and vine diseases. The object of viticulture is to produce the best quality grapes from the available soil. These grapes should be well balanced between the sugars, acids and tannins to produce the style of wine desired. In modern times, grape production has been increasingly subjected to science based technology and some producers are now growing grapes on an industrial scale.
1) The Type of Grapes
Most quality wine is produced from the Vitis Vinifera species which originated in Europe and which dominates commercial wine production. There are thousands of varieties some of which have become better known than others. Famous red wine varieties include Merlot, Cabernet Sauvignon, Pinot Noir, Zinfandel and Shiraz (Syrah). Well known white wine varieties include, Sauvignon Blanc, Chardonnay, Pinot Grigio and Viognier. The variety of grapes grown influences the style and taste of the wine. In Europe, there is a tradition of matching grape varieties to the soil, weather and climate and this is reflected in quality control rules.
2) Soil
The soil plays a major role in agriculture; grape vines like to thrive in poor soils which are well drained. In a poor well drained soil the vine roots are encouraged to penetrate deeply to obtain both water and mineral nutrients. Poor soils reduce the crop yield which is associated with the production of finer quality wines. Richer soils produce higher yields and this is generally associated with lower quality wine. Much research has been made to into the concept of yield versus quality and there is now a modern emphasis on producing high quality grapes from higher yields. It is not only the soil which affect yield but also growing techniques.
The soil is often associated with the style of wine so, for instance, Champagne grapes grow better in chalky soils.
3) Climate
Climate is different to weather. Climate can be defined as the weather conditions averaged over a long period of time. Climate is influenced by latitude and altitude. In general, vines grow best between latitudes 30 and 50 degrees north or south of the equator. Outside of these latitudes the local conditions or micro-climate may allow viticulture. For example, closer to the equator vines can be grown at higher altitudes where the climate is cooler.
Winter should be cold enough to restrict the growth of the vines to rest them. It should produce frosts severe enough to kill insect pests and diseases but not so sever e as to kill the vine itself. There should be sufficient rain to replenish soil moisture.
Spring should be mild to encourage the growth and budding of the vine. There should be sufficient rainfall to replenish the soil’s moisture and water reserves.
The late spring or early summer should be warm to promote the flowering of the vine.
A hot and sunny summer is then needed to promote the development of the grape berry. Light rain is required to swell the growing grape. Sunny conditions are needed in late summer to start the ripening process.
Autumn needs to be sunny and dry to complete the ripening of the grapes.
4) Weather
Local weather conditions can either encourage the good growth of the vines or adversely affect it. Bad weather can either destroy the vines or reduce the size of the crop.
Heavy frost in spring can destroy roots and prevent the budding of the vine.
Hail in late spring and summer can damage young shoots and flowers and in late summer it can damage the developing fruits.
Heavy or prolonged rain in summer can swell the grapes too much and dilute the sugars, flavours and acids in the berries. Heavy or prolonged rain also encourages fungal and mould disease s and slows down late summer ripening.
In autumn, heavy rain delays the ripening of the grapes or delays the harvest. A damp atmosphere also encourages fungal rot
Strong winds can damage the vines when they are flowering or prevent pollination.
It should be noted that the quality of the vintage of a wine is controlled by the weather not the climate. Good weather in all seasons improves the vintage and its wine but bad weather can ruin the quality of the grapes leading to inferior quality wine.
5) Viticulture
The growing methods in the vineyard also have a considerable influence on the quality of the grapes produced. The growing conditions of the grapes are vital to the health of the vine, the quality of the grapes and the control of diseases and pests.
Climate change is now beginning to affect growing conditions in some regions. In Australia drought has lead to changes and advances in irrigation techniques. In Europe, Spain has been affected by drought, in the La Mancha region, and this has lead to changes in the quality control rules to allow irrigation. Climate change may also affect which grapes can be best grown in a region and may prompt further changes to viticulture and changes to the rules in Europe.
Rootstocks
Whilst the actual grapes are produced from the Vitis Vinifera species, the shoots of this vine are grafted onto the roots of American species of vines including: Vitis Berlandieri, Vitis Riparia and Vitis Rupestris,. American rootstocks are resistant to the insect louse Phylloxera Vastatrix which infests vine roots. This louse has spread throughout all vine growing regions of the world. In the late 19th century, this louse almost destroyed viticulture in France and other European countries. Virtually all vines grown throughout the world are European vines grafted onto American rootstocks and this includes the USA. Rootstocks are selected to suit local climate and soil conditions.
Vine Training and Pruning
Vine training and pruning are essential to maintain the origin and health of the grapes. Because European grapes are grafted onto American rootstocks, any shoots produced by the rootstock above the ground must be pruned away to prevent cross-pollination of the grapes and hybridisation. Equally, the canes and shoots of the European vine variety must be prevented from taking root as they are not resistant to the Phylloxera louse and the vines could be destroyed.
Vines are trained in a way which suits the local vineyard conditions, climate and soil. There are two main ways of training the vines:
Cane training where the main horizontal cane is cut off, in winter, to be replaced by a spare cane. Cane trained vines are trellised on wires supported by a frame.
Spur training as often seen on Bush vines. The main canes are not pruned back in the winter. Bush vines are either left un-supported or just supported by a pole. Other forms of spur trained vines are supported on wires and trellises.
There are numerous variations of both types of training and in some European Countries there are rules governing the training methods used.
Vines can be trellised high to avoid ground frosts or trained low to benefit, at night, from heat stored in stones in the soil.
Vine growth is also influenced by the distance between rows of vines and their orientation either to attract sunshine or avoid dampness etc.
Pruning and canopy management also affects the quality of the grapes and the yield, and is adapted to local growing conditions.
The Vineyard year
In winter the vines are allowed to rest. Pruning is used to train the vines and damaged trellises are repaired. The soil is fertilised if necessary. Any grafting is performed in late winter or early spring when the vines begin new growth.
In spring the ground around the vines is ploughed or hoed to aerate the soil. Spraying against pests and disease is started depending on rules. New vines are planted. Vine training and pruning is continued.
In summer, pest and disease control spraying continues according to rules and standards. The canopy is managed by pruning to ensure that vine growth is concentrated on the production of ripe grapes rather than excess leaf cover.
In autumn, the vintage or wine picking takes place. Vines are either hand picked or picked by machine depending on commercial and quality considerations. Some vineyards do not lend themselves to mechanisation because of geography or the spacing of the rows of vines.
Vineyard location
Vineyards need to be located on soil which is conducive to viticulture. The best wines are usually produced from vineyards located on limestone, chalk, gravel, schist, granite or volcanic based soils.
From a weather and climate point of view, the best location for a vineyard is on a slope for good drainage and facing the sun to attract light and heat.
6) Wine pests and Diseases and their Control
Wine pests and diseases create serious problems for the wine grower and must be controlled for economic and quality reasons.
Phylloxera Vastatrix or the Vine louse
This aphid is the most serious vineyard pest and it can only be controlled by using American rootstocks as described before.
Other Insects pests
Other insect pests, such as the grape berry moth, are controlled using insecticides when they become a problem. Organic growers, who are opposed to the use of pesticides, encourage natural insect predators such as ladybirds or predatory wasps.
Downy Mildew
This is caused by the Peronospera mould which thrives in damp conditions and can destroy leaves and grapes. It can be controlled by spraying with either Bordeaux mixture which is a mixture of copper sulphate, lime and water or Copper based sprays. Improved ventilation of the vines helps to prevent the damp conditions which encourage the mould.
Powdery Mildew
Powdery Mildew or Oidium is caused by a fungus which grows in both humid and dry conditions it can affect both the leaves and the grapes. Even a mild case can affect the photosynthesis in the plant leaves. It is controlled by sulphur or fungicides.
Grey Rot
This is caused by the Botrytis Cinerea, this fungus attacks the vine in wet or humid conditions but usually in autumn when the grapes start to ripen. Grey mould covers the leaves and grapes especially white varieties. Bunches of grapes with grey rot can give an unpleasant taste to the wine.
For certain styles of sweet wine, such as Sauternes or Monbazillac and the sweet wines of Germany, grey rot is encouraged, it is then called noble rot. The white grapes are allowed to develop the rot which dries out the grapes and increases the concentration of sugar to make the high quality dessert wines of these regions. Any unpleasant taste is masked by the sweetness of the wine.
7) General Considerations
The climate, weather, grape type, vineyard techniques and pest and disease management are all subjects which can fill many books. In the final analysis, all of these factors combine together to affect the quality of our vines and ultimately our wine.
8) Some questions
What direction is it best for a vineyard to face?
What causes powdery mildew?
Between what latitudes are the wine growing regions mainly located?
Name one type of vine training?
What is the definition of climate?
What is the name of a well known red wine grape?
What is the most important insect pest in the vineyard?
Why are European vines grafted onto American rootstocks?
Name a wine which is produced by grapes exposed to Noble Rot?
What can affect the yield of grapes?
Which soil is regarded as best for growing grapes?
What controls the quality of the vintage the weather or the climate?
In what season are vines left to rest?
In what season does the vintage take place?
What affect does strong wind have on the vine?
Why would vines be trellised high above the ground?
What is the name of a well known white grape?
What components of the grape should be well balanced?
wine course 1
Wine Course 1
What is Wine
Wine Course 1 – What is Wine
1) What is wine
Wine is a beverage produced from the partial or total alcoholic fermentation of fresh crushed grapes or grape must. Yeast ferments sugars in the grape must to produce alcohol (ethanol) and carbon dioxide. To produce alcohol the yeast must ferment in the absence of oxygen otherwise the yeast and sugars produce only carbon dioxide and water.
The origin of wine is uncertain but it is known to have been produced in the region of Georgia at around 6000 BC. The ancient Greeks and Romans regularly consumed wine and spread wine making across their empires.
In the nineteenth century Louis Pasteur discovered that micro-organisms were responsible for fermentation. In the case of wine, the yeast species Saccharomyces Cerevisiae is responsible for the production of wine. After this discovery wine making became a more technical process.
2) Wine Styles
There are four different styles or types of wine and each style is dependent upon the grapes and wine making techniques used to make the final product.
Light White
Light wines are the most commonly drunk. There are three styles: Red, White and Rosé. Red wine is, predominately, made of black grapes but some wines have white varieties in the blend. White wine is made from, predominately, from white grapes. Good quality Rosé is made from black grapes which are pressed lightly so that not too much red pigment is extracted. Poorer quality Rosé is made from a blend of red and white wine. Light wines are fermented in dry, medium and sweet styles. Dry wines are fermented until virtually all the sugar is used up. Medium wines are fermented to leave up to 45 grams per litre of sugar. Sweet wines are made from grapes with a higher level of sweetness or have unfermented grape juice added. The sugar levels of a sweet wine will be above 45 grams per litre.
Sparkling
Sparkling wines such as Champagne or Cava are produced by a second fermentation of the wine in the original bottle. Yeast and sugar are added to the dry wine to produce the secondary fermentation and carbon dioxide which is sealed in the bottle. This is called the Traditional Method or Méthode Champenoise. Other types of lower quality sparkling wine are made using a variation of the traditional method. The name of Champagne is legally protected. Sparkling wines are usually made in White or Rosé style but there are also some Reds. Sparkling wines are produced in extra dry, dry, medium and sweet styles.
Fortified or Liqueur wine
Liqueur wines such as Port and Sherry are fortified with grape spirit. Port style wines are fortified before fermentation is complete and this leaves some fruit sugar left in the wine to make a sweet style. Sherry style wines are fermented until all the sugar is used up and then fortified, and this leaves the wines dry. Any sweetness in Sherry is added ,after fortification, by adding sweet swine or unfermented grape juice. Port is made in Red or White style. Sherry is made in White, Amber or Mahogany style. Port is fortified to about 20% alcohol. Sherry is fortified to between 15.5% and 21% alcohol by volume depending upon style. Vins Doux Naturels are Port style wines produced in the South of France where the Port method of fortification was invented: the most famous reds are Rasteau and Banyuls, and the most famous whites are Muscat de Beaumes de Venise and Muscat de Rivesaltes.
Aromatised Wines
Aromatised wines, such as Vermouth, are usually liqueur wines which have been flavoured with herbs and spices. White Vermouth is dry or sweet and Red is sweet.
3) Quality Systems
European Union
In the European Union a rigorous quality system has been introduced based mainly on the French Appellation d'Origine Contrôlée (AOC or AC) regime. There are two types of wine: Quality Wine produced in a Specified Region (QWPRS) and Table Wine.
The quality wine rules control the following:
The name of the wine
Which vines are grown and where they are grown by region, district or even village.
Vine yard operations
The alcoholic strength of the wine
The crop yield
Taste and flavour standards
There are two types of quality wine: Appellation d'Origine Contrôlée is the top quality level and Vin Délimité de Qualité Supérieure VDQS).
The rules for VDQS wine are less strict and many wines are promoted to AOC after a number of years. There are moves to phase out this classification.
The Table wines rules for Vins de Pays (VDP) and Vins de Table are less strict still and allow for innovation and experimentation. Many excellent wines can be found in the VDP category.
Italy, Spain, Portugal and Germany have very similar systems.
Other Major Wine growing Countries
The USA, Australia, Chile and Argentina have much less strict rules, especially related to controls on the types of grapes grown in a region and the crop yields. This has lent itself well to naming conventions, thus a wine may be labelled Pinot Noir if the wine is made predominantly from that grape. In contrast, virtually all red wine from Burgundy, in France, is made from 100% Pinot Noir but this is not shown on the front label.
Both systems have their advantages and disadvantages: the USA and Australian systems allow for more innovation and are very much market led. In Europe, once you become familiar with the system it is possible to find wines which reflect regional character.
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