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WSET 3 (2nd Edition) > Chap 7: Common Elements in Winemaking and Maturation > Flashcards

Chap 7: Common Elements in Winemaking and Maturation Flashcards

This only contains the second part of the chapter that is not covered in my physical flash cards

1
Q

Name an adjustment which is very difficult

A

Removing sugar

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2
Q

Can alcohol be removed from wine?

A

Yes, after fermentation is complete

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3
Q

Where is acidification permitted?

A

In Europe - only permitted in warmer regions. Common in many warm and hot regions around the world.

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4
Q

How may deacidification be carried out?

A

Excess acid may be neutralized by the addition of an alkaline substance (the chemical opposite of an acid).

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5
Q

How does alcoholic fermentation work? What are the by-products of this process?

A

Yeast converts sugar into alcohol and CO2. The other by-products are heat and flavor compounds.

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6
Q

What yeast species is responsible for the majority of wine fermentation? Why?

A

Saccharomyces cerevisiae - due to its tolerance of relatively high levels of alcohol and SO2

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7
Q

Alcoholic fermentation will not start if the temperature is below?

A

5C (41F)

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8
Q

Why might alcoholic fermentation stop before all of the sugar is consumed?

A

If the yeast runs out of the nutrients they need (other than sugar) or if the temperature reaches over 35C (95F)

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9
Q

What may happen if sugar levels are very high?

A

Combination of high sugar levels and alcohol can be enough to stop the yeast from functioning. In extreme cases, if the sugar levels can be so high that yeast may even struggle to start the fermentation in the first place

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10
Q

If the wine maker wants to stop the fermentation before all of the sugar has been converted, what can they do?

A

Killing or filtering the yeast

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11
Q

How can yeast be killed?

A

Adding SO2 or by adding grape spirit

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12
Q

How can yeast be removed?

A

by using filtration - this will be done after the fermentation has been temporarily halted by chilling the fermenting wine to below 5C (41F)

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13
Q

What are two important ways a winemaker can control the fermentation?

A

Choice of yeast and temperature management

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14
Q

What choice does the winemaker have in determining the type of yeast to use?

A

Various ambient yeast strains found on the grape skins and in the winery or adding a cultured yeast strain to the must

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15
Q

What are the pros and cons of using ambient yeast strains?

A

Believed to increase the complexity of flavors in the final wine, but winemaker cant control exactly which yeasts are present. There may be some variation in batches making it unsuitable for high volume wine production.

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16
Q

What are commercially available cultured yeasts?

A

Individual strains of S. cerevisiae that have been specifically selected because they consistently perform and produce attractive flavors.

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17
Q

What are the pros and cons of using commercially available cultured yeasts?

A

They have been specifically selected because they consistently perform and produce attractive flavors. Some argue that they limit the potential complexity of the wine.

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18
Q

Why it temperature management important in winemaking?

A

If fermenting wine becomes too hot, yeasts are killed.

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19
Q

What are the benefits of fermenting at lower temperatures?

A

Avoids the loss of the most volatile aromas (which often have a floral character). Can encourage the development of fruity flavors in white wines.

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20
Q

What are the benefits of fermenting at higher temperatures?

A

Higher temperatures are necessary for the extraction of color and tannins from black grape skins.

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21
Q

What can be done with excess heat produced during fermentation?

A

It can be released by pumping over.

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22
Q

What is Malolactic Conversion? What does it do to the wine?

A

Lactic Acid Bacteria convert tart malic grape acid into softer lactic acids. MLC softens and reduces acidity, creates buttery flavors and also produces CO2.

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23
Q

When does Malolactic Conversion take place?

A

Typically oncer alcoholic fermentation has finished

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24
Q

How might MLC be encouraged?

A

Raising the temperature of the wine and not adding SO2 after the alcoholic fermentation.

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25
Q

How might MLC be avoided?

A

Storage at cool temperatures, the use of SO2 or filtering out the bacteria.

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26
Q

What are large dead yeast cells and grape fragments that settle to the bottom of the fermentation or storage vessel (after alcoholic fermentation takes place) referred to as?

A

The gross lees

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27
Q

If the gross lees are not removed, what can happen to the wine?

A

It can cause unpleasant aromas to develop in the wine.

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28
Q

What are the smaller particles of dead yeast cells called?

A

The fine lees

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29
Q

How are the fine lees often removed?

A

Sedimentation

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30
Q

Why might a winemaker choose to keep a white wine in contact with the fine lees during pre-bottling maturation?

A

To add extra flavors and a richer texture to the wine

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31
Q

What is the main alcohol in wine?

A

Ethanol

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32
Q

What components make up wine?

A

Water, Ethanol, Sugars, Tannins and Color, Acids (most important: tartaric, lactic and malic), and Aroma and Flavor compounds

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33
Q

When does blending take place?

A

It can take place at any stage during the winemaking process, but is mainly carried out after fermentation or during the maturation process.

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34
Q

Why may a wine be bottled after only a few months?

A

The winemaker may want to preserve as many primary fruit aromas as possible

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35
Q

Give an example of a premium wine which is only matured for a short time, in inert vessels before bottling

A

Premium Australian Riesling

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36
Q

What is the most important factor in determining how well a wine will survive medium to long-term ageing?

A

It needs sufficient levels of tannin, acidity and/or alcohol and it must have flavors that will develop in an interesting way.

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37
Q

What changes can occur during pre-bottling maturation?

A

The vessel can affect the wine’s flavors by adding oak flavors or allowing oxidation to take place.
Over time, components in the wine can react with each other, altering flavor or the balance (and sometimes creating sediment in the vessel, which is periodically removed)

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38
Q

Give an example of when blending may be used to improve balance

A

When making red wine, free run wine may be blended with press wine to increase tannins in the final product.

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39
Q

Give an example of when blending may be used to achieve consistency

A

Wines matured in small barrels can develop in subtly different ways and may be blended together in a large vat to smooth out inconsistencies.
Variations may arise due to differences in fruit (harvested at different times or from different vineyards) or due to slight inconsistencies that may arise during winemaking.

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40
Q

How may a winemaker go about achieving their ‘house style’

A

By creating as many blending options as possible during the winemaking process

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41
Q

List some variations of blends that a winemaker may create

A

Separating press fractions
Fermenting/maturing in different vessels
Allowing only a proportion to go through MLF
Using different grape varieties
Different vineyard plots
Different vintages

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42
Q

What are the three main techniques a winemaker may use to clarify a wine?

A

Sedimentation
Fining
Filtration

43
Q

Why may a wine not go through all clarification treatments?

A

Because some winemakers believe that some of the treatments may harm the character of the wine

44
Q

When will sedimentation usually take place?

A

After alcoholic fermentation has finished.

45
Q

What is racking?

A

Once the gross lees have settled in a deposit, the wine is gently pumped into another vessel, leaving the sediment behind.

46
Q

Wine will continue to throw a deposit of fine lees during maturation - how can the clarity of the wine be gradually improved?

A

Racking may be repeated several times during maturation

47
Q

How may sedimentation be accelerated? What is the disadvantage of this?

A

By putting wine in a centrifuge, but the equipment is very expensive.

48
Q

How is fining performed? Why is it performed?

A

By adding a fining agent to the wine, it speeds up the process of deposits clumping together, so that they can be removed (via filtering) prior to bottling.

49
Q

Why may a winemaker not add a fining agent to a wine?

A

Some winemakers believe it can adversely affect flavor and texture.

50
Q

What is filtration?

A

A process that physically removes particles from a wine as it is passed through a filter.

51
Q

When may filtration be performed?

A

After fermentation, during maturation (to remove the gross and fine lees quickly) and before bottling (to ensure the wine is clear).

52
Q

What are the two methods of filtration?

A

Depth filtration and Surface filtration

53
Q

What is depth filtration and what does it involve?

A

The filters used in this process are made from a thick layer of material, so as the wine passes through the filter the solid parts become trapped inside of this material.

54
Q

What can depth filtration achieve?

A

It can handle very cloudy wines and can be used to remove gross lees.

55
Q

What is surface filtration and what does it involve?

A

The filters used for surface filtration resemble very fine sleves. The solid particles are trapped on the surface of the filter as the wine flows through it.

56
Q

What are the disadvantages of surface filtration? How are they mitigated?

A

Filters are very expensive and clog very easily, so they are generally used for wines that have already been passed through a depth filter.

57
Q

What is sterile filtration?

A

Where the pores in a surface filter are small enough to remove yeast cells and bacteria that still may be present in wine.

58
Q

When may sterile filtration be performed?

A

As a final treatment prior to bottling.

59
Q

Why are some bottles unfiltered?

A

Some winemakers believe that filtration can negatively affect a wine’s character, especially its texture.

60
Q

When is a wine considered stable? Why does this vary?

A

If over a specific time, it changes in a slow, predictable manner.
The rate and amount of change deemed acceptable will vary from wine to wine.

61
Q

Name a stabilisation process and explain why it is considered to ‘stabilise’

A

Fining, which helps with clarity, can therefore also be seen as a stabilisation process because it aims to produce a predictable outcome after bottling.

62
Q

Other than fining, name three other important areas that require stabilisation.

A

Tartrate stability
Microbiological stability
Oxygen stability

63
Q

Why can tartaric acid crystals form in wine? What are they called?

A

Tartaric acid is less soluble in wine than in grape juice and over time it can form crystals called ‘tartrates’.

64
Q

What do Tartrates look like?

A

Clear crystals in white wine
Purple crystals in red wine (stained by color compounds)

65
Q

What is the big disadvantage of Tartrates?

A

They spoil the appearance of the wine

66
Q

How is the formation of Tartrates accelerated?

A

In cool temperatures (ex: if a wine undergoes a long maturation period in a cool cellar prior to bottling it will deposit some of its tartrates during maturation.)

67
Q

In a situation where a long maturation is inappropriate, what might a winemaker do to force tartrates to form prior to bottling?

A

By chilling the wine to below 0C (32F) for a short period of time.

68
Q

How are tartrate crystals removed?

A

Filtration

69
Q

Why are yeast and bacteria undesirable in wines?

A

They can spoil a wine and make it completely undrinkable and unfit for sale.

70
Q

Why is it important to keep equipment sterile from a microbiological perspective?

A

Undesirable microorganisms can thrive in grape and wine residues.

71
Q

What is the only type of wines that are not at any risk from microbiological contamination? Why?

A

Fortified wines, because the high level of alcohol they contain is toxic for all microorganisms.

72
Q

What type of wine is naturally quite resistant to microbiological spoilage? Why?

A

A dry high acid wine that has undergone malolactic conversion. The alcohol, acidity and lack of nutrients mean that most yeast or bacteria struggle to survive.

73
Q

Which types of wines are at particular risk from yeast or bacterial spoilage?

A

Wines that have not undergone MLC, as well as wines with low-med alcohol, low acidity and a little risidual sugar.

74
Q

How are more susceptible wines treated to prevent spoilage?

A

With an appropriate amount of SO2 at all times and sterile filtration prior to packaging.

75
Q

How may oxidation risk be reduced in a wine?

A

Minimizing oxygen contact and keeping SO2 topped up.

76
Q

Name an extra measure a winemaker may take during packaging to minimize oxidation risk.

A

The bottle may be flushed with CO2 or nitrogen before filling to eliminate oxygen.

77
Q

What are the benefits of packaging wine in glass bottles?

A

Portable
Cheap to produce
Quite strong
Oxygen impermeable
Do not taint the wines flavors
Remains consumers preferred form of packaging

78
Q

What are the disadvantages of packaging wine in glass bottles?

A

They are heavy and rigid
Weight adds to transport costs
Rigidity means it cannot be packed to make best use of the available space
Rigidity also means that once opened, a part-filled bottle will contain space for air, at which point the wine is vulnerable to oxidation.

79
Q

For environmental and cost purposes, how have a number of producers changed their bottling practices?

A

Using lighter weight glass bottles and some transport their wine in bulk to be bottle in (or nearer to) the country where the wine is to be sold.

80
Q

What is the main disadvantage of plastic bottles for wine?

A

They are slightly oxygen permeable and wines may lose their freshness over a period of months.

81
Q

What is the advantage of bag-in-box wines?
What is the disadvantage?

A

The bag collapses as wine is drunk, preventing air from entering, however the plastic bag is still oxygen permeable.

82
Q

Within what time period must a bag-in-box wine be consumed? Why?

A

Within 18 months of being filled, as the plastic bag is oxygen permeable.

83
Q

What factors may dictate the type of closure which is used for a bottle?

A

Ease of use
Which closures a bottling line is designed to use
For bottles intended for maturation, it must allow the wine to mature positively

84
Q

What does a slow release of oxygen allow in some wines?

A

The development of tertiary flavors

85
Q

What does an airtight closure allow?

A

Retention of fresh fruit flavors

86
Q

Why may a winemaker not be able to choose their bottle closure?

A

It may be overridden by the preference of the consumer market

87
Q

What is the most widely used bottle closure?

A

Cork

88
Q

What is the closure of choice for many wines intended for bottle maturation? Why?

A

Cork, because it allows very small amounts of oxygen to enter the wine, thus achieving what many winemakers would consider the optimal balance between primary and tertiary characteristics.

89
Q

What are the two problems with cork-closed wines?

A

Cork taint and oxidation

90
Q

What causes cork taint? What does it do to the wine?

A

A chemical called trichloroanisole (TCA) which gives the wine a moldy, cardboard-like aroma.

91
Q

What are technical corks made from?

A

Agglomerated cork

92
Q

What are the simplest technical corks?

A

Pieces of cork bound together in a typical cork shape with a form of glue or plastic.

93
Q

What are the pros and cons of ‘simple’ technical corks?

A

They are cheaper than natural corks, but are only suitable for wines that are to be drunk within a couple of years of production.

94
Q

How are technical corks made for with premium wines in mind?

A

They are often made from cork granules that have been subjected to a manufacturing process that minimizes or eradicates TCA. They can be made to permit a very slow ingress of O2 and hence can be suitable for wines for long-term cellaring.

95
Q

Who has championed the use of screw caps?

A

Producers from Australia and New Zealand

96
Q

How are synthetic corks generally made?

A

From some form of petrochemical-based or plant-based plastic.

97
Q

Are synthetic corks suitable for wines for long-term cellaring?

A

Previously they only used to be suitable for wines to be consumed within a year of bottling, but there are now several premium versions on the market that allow long term storage.

98
Q

What are the benefits of screw caps?

A

They do not taint wine, can easily be opened by hand without needing any equipment and can be resealed.

99
Q

What have some research trials shown about screw caps?

A

They preserve fruit flavor in wine longer than cork and some types permit lower oxygen ingress than cork.

100
Q

Within what time are the majority of wines best consumed?

A

One year

101
Q

What happens to wines not intended for aging when kept in bottle for more than a year?

A

They lose their primary fruit flavors

102
Q

Give examples of wine styles which can mature in bottle for several years and are not at their best immediately after bottling

A

Vintage Port
The finest German Rieslings
Bordeaux Crus Classés

103
Q

Any aging in bottle should be spent in what conditions?

A

Undisturbed in a cool dark place with a constant temperature (ideally around 10-15C / 50-59F) and constant humidity. Additionally if sealed with a cork, the bottles should be stored lying on their side, so that the cork remains moist and an optimum seal is maintained.

WSET 3 (2nd Edition) (11 decks)

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