C7 - Common Elements In Winemaking And Maturation /checked Flashcards
(209 cards)
1
Q
What is the next stage in winemaking after harvest?
A
The grapes are processed and prepared for alcoholic fermentation
2
Q
On a basic level, what is alcoholic fermentation?
A
Yeast converts sugars in the grape to alcohol
3
Q
What is the next basic stage of winemaking after alcoholic fermentation?
A
The wine needs to be stored prior to packaging and sale
4
Q
Broadly speaking, what are natural wines?
A
Wines made with minimal intervention
5
Q
Describe the seeds and stems of the grape
A
Both contain tannins
Seeds contain high levels of bitter oils
6
Q
How are stems made available to the winemaker (what harvest method)
A
By hand harvesting
7
Q
Why is the grape skin important to the winemaker? (3)
A
It contains:
- Flavour: the skin and the area immediately underneath, contain high levels of flavour compounds (containing the grape’s signature character)
- Tannins
- Colour compounds
8
Q
Describe tannins at Véraison
How does this change?
A
They taste very bitter and astringent
As grapes ripen, bitterness and astringency fall
9
Q
What is the Bloom of a grape?
What essential product dos it contain?
A
The waxy surface that covers the skin of a grape
It contains yeast that can be used for fermentation
10
Q
List the 3 major constituents of a grape’s pulp
A
- Water
- Sugar
- Acid
11
Q
What is the largest constituent of a grape’s pulp?
A
Water
12
Q
What is the second largest constituent of a grape’s pulp?
A
Sugar
13
Q
In order, what are the most abundant acids in a grape’s pulp? (2)
A
- Tartaric acid
2. Malic acid
14
Q
What can oxygen react with during winemaking and maturation? (2)
A
- Grape juice
2. Many of the component parts of a wine
15
Q
What is oxidation?
A
Oxygen reacting with any component part of a wine
16
Q
What is the biggest threat to a winemaker wanting their wine to be dominated by primary fruit characteristics?
A
Oxidation
17
Q
How is the risk of oxidation broadly avoided by a winemaker? (2)
A
- Keeping oxygen contact to a minimum
2. Use of antioxidants such as Sulfur Dioxide
18
Q
Why might grapes be picked at night? (in relation to oxidation threat)
A
It is cooler and the effect of oxygen is reduced because chemical reactions occur more slowly at lower temperatures
19
Q
How are grapes kept away from oxygen once they reach the winery?
What is this process called?
A
By filling airtight winery equipment with carbon dioxide or nitrogen before they are used for grape processing or winemaking
Protective/anaerobic winemaking
20
Q
What is the argument against anaerobic winemaking?
A
Some argue that the resultant wines may be bland or uninteresting and that a higher level of oxygen contact helps to develop complexity and character
21
Q
Do wines that have been protected from oxygen during wine making benefit from oxygen contact during maturation?
A
No.
Wines that have been protected from oxygen during wine making rarely if ever benefit from oxygen contact during maturation.
22
Q
How are anaerobically made wines stored?
A
In inert airtight vessels which are kept completely full
The vats are made from stainless steel or cement lined with epoxy-resin
23
Q
How are aerobically made wines usually stored?
A
In wooden vessels that are normally made of oak
24
Q
Is Oak watertight?
Is Oak airtight?
A
Oak is Watertight
Oak is not Airtight (mild oxygen permeability)
25
How does the mild oxygen permeability of oak help a wine? (2)
1. It can help to soften tannins in red wines
| 2. Gives more flavour complexity
26
What happens to flavours in wine during deliberate oxidation/maturation?
1. Primary fruit flavours gradually fade
| 2. Tertiary characters start to develop, such as leather and earth
27
How does oxidation affect the colour of wine? (answer for both Red and White)
Red wines become paler and gain a hint of brown
| White wines become deeper in colour and gain a hint of orange
28
What two main factors influence the amount of deliberate oxidation a wine receives? (2)
1. Size of vessel
| 2. Length of time stored in it
29
How does barrel size affect the amount of oxidation a wine receives? Why?
Smaller barrels have a greater oxidative effect.
They present a proportionately larger surface area of wood to the wine.
30
How large is a Barrique? (Bordeaux)
How large is a Pièce? (Bourgogne)
Barrique: 225 litres
Pièce: 228 litres
31
Wines are rarely kept in barriques for longer than how much time?
Two years, due to its small size (high level of oxidation)
Wines kept in larger oak vessels may be matured for longer.
32
How may the effect of barrel oxidation be further enhanced?
If the container is not completely full
33
Name 3 wines which are matured in barrels which are not completely full (deliberate oxidative)
1. Oloroso Sherry
2. Rutherglen Muscat
3. Tawny Port
34
What characters do wines which are deliberately aged take on?
Pronounced tertiary characters of Caramel, Toffee and Nuts
35
What may happen to a wine if it's exposed to too much oxygen?
It can lose much of its fruit flavour and smell stale
36
What can happen to over-oxidised wine in extreme cases?
Bacteria can use the oxygen to turn the wine to vinegar
37
What are the main uses of Sulfur Dioxide in a winery? (2)
1. Antioxidant effects
| 2. Antiseptic effects
38
```
Which element (additive) in wine making can be toxic (and a allergen)?
How is this controlled?
```
```
Sulfur Dioxide (SO2)
It is regulated by law
```
39
Why might a quality-conscious winemaker want to keep SO2 levels as low as possible?
It can make wines seem harsh and lacking in fruit
40
When used as an antioxidant, why must SO2 levels be constantly monitored?
By protecting wine from oxidation, SO2 becomes 'bound' and can have no further protective use
41
Why is SO2 effective as an antioxidant?
It is toxic to the many strains of yeast and bacteria that can cause unwanted flavours in wine
42
Is SO2 toxic to the principal fermentative yeast involved in winemaking?
No, this strain is resistant to certain levels of SO2
43
Other than providing oxygen, what can oak ageing add to a wine?
1. Tannins
| 2. Flavours
44
What does oak-tannin give to a wine?
Structure/textural complexity
45
What kind of flavours can oak give to a wine? (sample 4)
1. Toast
2. Vanilla
3. Smoke
4. Cloves
46
What is a particular challenge when using oak for maturation? Why?
Hygiene
| It is particularly difficult to keep wooden vessels free of yeasts, bacteria and moulds
47
Why may a winemaker use different types of vessel during maturation?
As oak vessels differ widely in their characteristics
| To enhance complexity in their wines
48
What are the 4 major factors to consider when choosing oak for maturation?
1. Species and origin of oak
2. Size
3. Production of oak barrels (extend of toasting)
4. Age
49
Describe why species of oak is an important factor in flavour characteristics
Flavour can change, even within a species of oak
| also grain - permeability
50
Where is some of the finest oak considered to be from?
Some forests in France
51
How large can wine maturation vessels get?
Beyond 2000 litres
52
What is one of the most important barrel production procedures when it comes to how a barrel affects the flavour of a wine?
Toasting
53
How are the barrel's staves prepared so they can be bent into shape?
They are heated
54
What secondary effects does the heating of a barrel's staves have?
It transforms the tannins and the flavour compounds in oak
55
What flavours are newly produced by a barrel once it is toasted? (2)
1. Sweet spice
| 2. Toast
56
What does 'level of toasting' refer to in the making of a barrel?
The temperature and length of heat exposure
57
What affects the flavours a barrel can give to a wine?
The level of toasting
58
What happens each time a barrel is used?
The effect of toasting diminishes
The amount of flavour and tannin the barrel imparts diminishes.
near zero at 4th usage
59
Why might a winemaker not use new oak?
In order to make a wine with subtler or NO oak flavours
60
How else may oak flavours and tannins be added to a wine, other than using barrels?
What is the advantage of doing this?
By using oak staves or oak chips
| It's cheaper
61
How may the oxidative effects of barrel ageing be replicated?
By adding small, controlled quantities of oxygen to the wine vessel
62
What is an inert wine vessel?
It does not add flavour to the wine or allow oxidation
No flavour, No oxidation.
63
What are the majority of inert winery vessels made from?
Stainless steel or (lined) concrete
64
What can inert winery vessels be used for? (2)
1. Fermentation
| 2. Temporary storage of wine after it is finished
65
What are most modern winery vessels made from?
Stainless steel
66
List the advantages of stainless steel as a winery vessel (3)
1. Easy to keep clean
2. Can be made into any shape and size
3. Can incorporate temperature control mechanisms
67
What are the 2 main types of temperature control mechanisms?
1. Sleeves on the outside of the vessels
| 2. Internal coils through which cold or hot liquid can be circulated
68
What are concrete vessels usually lined with? What does this do?
Epoxy resin
| It's inert and provides a waterproof barrier
69
What was commonly used as inert vessels before stainless steel?
Concrete vessels
70
What are the disadvantages of concrete vessels over stainless steel?
They can be less easy to clean and maintain
71
Why might some winemakers prefer concrete vessels?
The thick concrete shells help to regulate temperature during fermentation and maturation without the need for expensive equipment
= cheaper
72
Name a wine vessel which is not steel or concrete.
Glass bottles
73
When do grapes usually receive their first dose of SO2?
When they arrive at the winery
74
Besides receiving SO2, what else may happen to wine grapes during reception?
They may be individually checked and sorted for unripe and rotten grapes
75
What is the next possible stage after grape reception?
Destemming and crushing
76
What does crushing do?
It breaks the skin of the grapes and liberates a quantity of juice
77
What is the liquid product of crushing called?
Free run juice
78
What is the danger when crushing grapes?
If the seeds are crushed, they will release bitter oils and tannin
79
What does pressing do?
It separates the liquid and solid constituents of the grape
80
Why are modern pressing techniques designed to be gentle?
As with crushing, to avoid crushing the seeds
81
What is the traditional design of grape presses?
They were all vertical
82
How does a vertical press work?
| What is a traditional vertical press called?
The pressure on the grapes comes from above, using a screw or lever
A basket press
83
Name a wine producing region which is still particularly known for its vertical presses
Champagne
84
Describe a pneumatic press
An inflatable rubber tube within a perforated, horizontal stainless steel cylinder
85
What does a pneumatic press allow that a vertical press does not?
It's possible to apply pressure over a larger area in a controllable way
86
Why are some presses built within a closed tank?
So that the amount of oxygen in contact with the juice is kept to a minimum
87
What are fractions?
Different pressings of grape juice/wine
They differ in flavour and texture.
88
What may be done with different 'fractions'?
They may treated individually and blended in different proportions to create a certain style
89
When may adjustments of the major components of the juice or wine take place? (sugar, alcohol, acid)
Before, during or after fermentation
90
How is grape juice commonly referred to?
Must
91
What is the term for the level of sugar in grape juice?
Must weight
92
How may sugar be increased in a wine? What is it called?
By adding Rectified Concentrated Grape Must (RCGM)
This is called Enrichment
93
What is Rectified Concentrated Grape Must?
A colourless, odourless, syrupy liquid
94
At what stage may a must be enriched?
Before or during fermentation
95
Is Enrichment freely allowed during wine making?
NO
Enrichment is banned in many parts of the world.
If it is permitted, it is strictly controlled.
96
What may happen to a wine if the process of enrichment is abused?
It may become hard and thin
| Because there are insufficient flavours to balance the artificially elevated alcohol
97
What is Chaptalisation?
Sugar (from sources other than grapes) is added as a form of Enrichment
98
Other than enrichment, how else may alcohol levels be raised in a must/wine?
By removing water from the must
99
What are the disadvantages of removing water to concentrate sugar/alcohol?
As well as sugar, it concentrates tannins, acids, flavour compounds and faults
It reduces volume too
100
Is removing sugar from the Must easy?
NO
| Removing sugar is very difficult
101
Can alcohol be removed from wine?
Yes, after fermentation is complete
102
How is acid usually increased in a wine?
By the addition of tartaric acid in powder form
103
Where is acidification permitted?
In Europe, only in warmer regions
| In many hot countries around the world
104
How may a wine be de-acidified?
By the addition of an alkali
105
What are the inputs and outputs of fermentation?
Input: Sugar and Yeast
Output: Alcohol and CO2 (+ Heat + Flavour)
106
What are the 'other' by-products of fermentation?
Heat and flavour compounds
107
Which yeast species is responsible for the majority of wine fermentations?
Why is this used?
Saccharomyces Cerevisiae
Due to its tolerance of relatively high alcohol levels and SO2
108
What is the minimum temperature at which fermentation can begin?
5 Celsius
109
At what point does fermentation naturally stop?
When all the sugar has been consumed
110
What may stop fermentation before all sugar has been consumed? (5)
1. Lack of nutrients
2. Temperature: over 35C or under 5C
3. High alcohol
4. High sugar
5. Remove yeast
111
What may happen to fermentation if sugar levels are very high?
Fermentation may not even start
112
Broadly speaking, how may a winemaker deliberately halt fermentation? (2)
1. By killing yeast (SO2 or fortification)
| 2. By removing yeast (filtration under 5C)
113
How may yeast be killed? (2)
1. Adding SO2
| 2. Adding grape spirit (fortification)
114
What are the two important ways in which a winemaker may control fermentation? (2)
1. Choice of yeast
| 2. Temperature management
115
What are the 2 general groups of yeast can a winemaker opt for?
1. Ambient yeast strains (on the grape bloom
| 2. Cultured yeast strains (manually added to the must)
116
What is the advantage of using ambient yeast strains?
It can produce complex flavours in the final wine
117
What is the disadvantage of using ambient yeast strains? (2)
1. LACK OF CONTROL (The winemaker cannot control exactly which yeast strains are present)
2. VARIATION (There may be some variation between batches of grapes)
118
What are commercially available yeasts?
Strains of Saccharomyces Cerevisiae that have been specifically selected because they consistently perform and produce attractive flavours
119
What is a potential argument against using cultured yeasts?
That it can limit the potential complexity of the wine
120
Why is temperature management important in the winery? (2)
1. If fermenting wine becomes too hot, yeast are killed
| 2. By controlling temperature, the winemaker can influence the wine's flavours
121
What is achieved by fermenting at lower temperatures? (2)
1. Retain FLORAL (It avoids the loss of most volatile aromas which often have a floral character)
2. Retain FRUITINESS (It can encourage the development of fruity aromas in white wines)
122
What is achieved by fermenting at higher temperatures?
Better extraction of Colour and Tannins from black grape skins
123
Other than cooling, how may excess heat be releases during fermentation?
By pumping over
124
Name a winemaking technique which has been pivotal in quality and consistency of modern winemaking
Precise temperature control
125
When does malolactic fermentation usually take place?
Once alcoholic fermentation has finished
126
What carries out MLF?
Lactic Acid bacteria
127
What happens during MLF?
Lactic acid bacteria convert tart malic grape acid into softer lactic acid
128
What does MLF broadly do? (3)
1. Softens and reduces acidity
2. Creates buttery flavours
3. Produces CO2
129
How may MLF be further stimulated? (2)
1. By raising the temperature of the wine
| 2. Not adding SO2
130
How may MLF be avoided? (3)
1. Through storage at cool temperatures
2. Use of SO2
3. By filtering out the bacteria
131
Why may wine appear cloudy after fermentation? (2)
1. Dead yeast cells
2. Grape fragments
The offending particles are usually heavy enough to fall to the bottom of the vessel within a few hours
132
What is the sediment that falls to the bottom of the vessel after fermentation?
GROSS lees
133
What is the result of GROSS lees are not removed?
Unpleasant aromas can develop in the wine
134
What are FINE lees?
Smaller particles in the wine after fermentation (which settle more slowly)
135
How are FINE lees removed?
They are removed gradually during the wine maturation process
136
Why may a winemaker not want to remove the fine lees during pre-bottle maturation?
To add extra flavours and a richer texture to the wine
137
Why may a wine be bottled after only a few months (or sooner)?
The winemaker may want to preserve as many primary fruit aromas as possible
138
Give an example of a premium wine which is only matured for a short time, in inert vessels before bottling
Premium Australian Riesling
139
What is the most important factor in determining how well a wine will survive medium to long-term ageing? (4)
1. Tannin
2. Acidity
3. Alcohol
4. Flavours that will develop in an interesting way
140
What changes can occur during pre-bottling maturation?
The vessel can affect the wine's flavours by adding oak flavours or allowing the wine to oxidise.
Over time, wine components can react with each other, altering flavour or balance (and sometimes creating sediment in the vessel, which is periodically removed)
141
When does blending take place?
It can take place AT ANY STAGE during wine making
142
When does blending usually take place?
After fermentation or during maturation
143
What is blending used to achieve? (3)
1. Improve BALANCE
2. Attain CONSISTENCY
3. Achieve a certain STYLE
144
What may impede blending?
Local laws (e.g. in relation to appelation)
145
Give an example of when blending may be used to improve BALANCE
When making red wine, free run wine may be blended with press wine to increase tannins in the final product
146
Give an example of when blending may be used to achieve CONSISTENCY (3)
1. Wines matured in small barrels can develop in subtly different ways and may be blended together in a large vat to smooth out inconsistencies.
2. Variations may arise due to differences in fruit (harvested at different times)
3. Inconsistencies may arise during winemaking
147
How may a winemaker go about achieving their 'house style'
By creating as many blending options as possible during the winemaking process
148
List some variations of blends that a winemaker may create (6)
1. Separating press fractions
2. Fermenting/maturing in different vessels
3. Allowing only a proportion to go through MLF
4. Using different grape varieties
5. Different vineyard plots
6. Different vintages (e.g. champagne)
149
What are the 3 main techniques a winemaker may use to clarify a wine?
1. Sedimentation
2. Fining
3. Filtration
150
Why may a wine not go through all clarification treatments?
Because some winemakers believe that some of the treatments may harm the character of the wine
151
What is RACKING?
Once the gross lees have settled in a deposit, the wine is gently pumped into another vessel, leaving the sediment behind
152
How are FINE lees dealt with after racking?
Racking may be repeated several times during maturation
153
For some fine wines, what 2 clarification methods only will be used?
1. Sedimentation
| 2. Racking
154
What is the major disadvantage of natural sedimentation as a means of clarification?
It is very slow
155
How may sedimentation be accelerated?
What is the disadvantage of this?
Centrifuge use
The equipment is very expensive
156
What is fining?
It speeds up the process of deposits clumping together in a wine so that they can be removed
157
How is fining performed?
By adding a fining agent to the wine and removing the clumps that appear
158
Why may a winemaker not add a fining agent to a wine?
Some winemakers believe it can adversely affect flavour and texture
159
What is filtration?
A process that physically removes particles from a wine as it is passed through a filter
160
When may filtration be performed? (3)
1. After fermentation
2. During maturation
3. Before bottling
161
What are the 2 methods of filtration?
1. Depth filtration
| 2. Surface filtration
162
Describe the filter used in Depth Filtration
They are made from a thick layer of material
163
Describe Depth Filtration
As wine passes through the filter, the solid parts become trapped inside it
164
What can Depth Filtration achieve?
It can handle very cloudy wines and remove Gross Lees
165
Describe filters in Surface Filtration
They resemble very fine sieves
166
How does surface Surface Filtration work?
Solid particles are trapped on the surface of the filter as wine passes through
167
What are the disadvantages of Surface Filtration? (2)
1. Filters are very expensive
| 2. Filters clog very easily
168
How is the expense of surface filtration minimised?
By only using it after depth filtration
169
What is Sterile Filtration?
Where the pores in a surface filter are small enough to remove yeast cells and bacteria
170
When may Sterile Filtration be performed?
Just before bottling
171
Why are some bottles unfiltered?
Some winemakers believe that filtration can negatively affect a wine's character, especially its texture
172
When is a wine considered stable? Why does this vary?
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
173
Stabilisation
When is a wine considered to be stable?
If, over a specified time frame, the wine changes in a slow specific manner.
174
Name 3 important areas that require stabilisation
1. Tartrate stability
2. Microbiological stability
3. Oxygen stability
175
Why can tartaric acid crystals form in wine?
What are tartaric acid crystals called?
Tartaric acid is less soluble in wine than in grape juice
Tartaric acid crystals are called TARTRATES
176
What do Tartrates look like in both white and red wine?
Clear crystals in white wine
| Purple crystals in red wine (stained by colour compounds)
177
What is the big disadvantage of Tartrates?
They spoil the appearance of the wine
178
How is the formation of Tartrates accelerated?
In cool temperatures
179
How may a winemaker remove Tartrates?
COLD STABILIZATION + Filtration
| = briefly chilling the wine to below 0C
180
Why can yeast and bacteria be undesirable in wines?
They can spoil a wine and make it undrinkable
181
Why is it important to keep equipment sterile from a microbiological perspective?
Undesirable microorganisms can thrive in grape and wine residues
182
Which wines may not be at risk from microorganisms?
Fortified wines
| Their alcohol levels are toxic for all microorganisms
183
Name a non-fortified wine which is highly resistant to microbiological spoilage
A dry, high-acid wine that has undergone MLF
184
Which wines are most prone to microbiological spoilage?
Low acid, low alcohol wines, which have not undergone MLF and have a little residual sugar
185
How are more susceptible wines treated to prevent spoilage? (2)
1. SO2 use
| 2. Sterile filtration
186
How may oxidation risk be reduced in a wine? (2)
1. Minimising oxygen contact
| 2. Keeping SO2 topped up
187
Name an extra measure a winemaker may take during packaging to minimise oxidation risk
The bottle may be flushed with CO2 or nitrogen before filling to eliminate oxygen
188
What are the advantages of glass bottles? (5)
1. Portable
2. Cheap
3. Quite strong
4. Oxygen impermeable
5. Do not impart flavours to wine
189
What are the main disadvantages of glass bottles? (4)
1. Heavy = costs
2. Rigid = costs
Rigidity means it cannot be packed to make best use of the available space
190
How are the disadvantages of using glass bottles being counteracted? (2)
1. Some producers are using lighter bottles
| 2. Some bottle in or closer to the destination country
191
What is the main disadvantage of plastic bottles for wine?
They are slightly OXYGEN PERMEABLE and wines may lose their freshness within a matter of months
192
What is the advantage of bag-in-box wines?
| What is the disadvantage?
The bag collapses as wine is drunk, preventing air from entering
The plastic bag is still oxygen permeable
193
Within what time period must a bag-in-box wine be consumed?
18 months
194
What does a slow release of oxygen (through the cork) allow in some wines?
The development of tertiary flavours
195
What does an airtight closure allow?
Retention of fresh fruit flavours
196
Why may a winemaker not be able to choose their bottle closure?
It may be overridden by the preference of the consumer market
197
What is the most widely used bottle closure?
Cork
198
What is the major benefit of cork as a wine closure?
CORK IS PERMEABLE
It allows very small amounts of oxygen to enter the wine, thus allowing the development of sometimes desired tertiary flavours
199
What are the 2 main problems with cork-closed wines?
1. The risk of cork-taint
| 2. Risk of oxidation
200
What chemical causes cork taint?
Trichloroanisole (TCA)
201
What effect does TCA have on a wine?
Gives wine a mouldy, cardboard-like aroma
202
What are synthetic corks made from?
Some form of plastic
203
What is the disadvantage of synthetic corks as closures?
Generally only suitable for wines intended for early consumption
204
What countries lead the use of screw caps?
Producers from Australia and New Zealand
205
What are the advantages of screw caps as closures? (2)
1. They do not taint wine
2. They provide an impermeable seal from air (They preserve fruit flavour in wine longer than cork)
and cheap
206
How has the disadvantage of screw caps as a closure been countered by some producers?
Some screw caps have been designed to have some oxygen permeability
207
Within what time are the majority of wines best consumed?
One year
208
What happens to wines not intended for ageing when kept in bottle for more than a year?
They lose their primary fruit flavours
209
Give examples of wine styles which can mature in bottle for several years and are not at their best immediately after bottling (3)
1. Vintage Port
2. The finest German Rieslings
3. Bordeaux Crus Classés
