Chapter 7 - Common Elements in Winemaking Flashcards

1
Q

Name the parts of the grape

A

Skin - high concentration of flavour compounds. Also contains tannins and colour compounds

Seeds and stems - contain tannins and bitter oils

Bloom - the waxy surface that covers the skin

Pulp - contains water, sugar and acids (mostly tartaric, a bit malic)

Tannins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the chemical process of oxygen reacting with wine reffered to as?

A

Oxidation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What flavours does oxidation take away from wine?

A

Primary fruit characteristics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What anti-oxidant is often used?

A

Sulfur Dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some techniques to counter the effects of oxygen in winemaking?

A
  • harvest at night when it is cooler
  • keept the grapes chilled as long as possible during and after harvest
  • keep the grapes and juice away from oxigen with airtight equipment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Why do lower temperatures help against oxidation?

A

Chemical processes go slower in lowe temperatures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What gasses are used to keep machinery airtight?

A

Nitrogen and Carbon Dioxide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is winemaking with the least amount of oxigen referred to as?

A

Anaerobic winemaking

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Can you mature wines that have been made anaerobicly in oak vessels

A

No, wines made in that way don’t benefit from any contact with oxigen during maturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What airtight maturing vessels are there?

A
  • stainless steel

- cement lined with epoxy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What can contact with very small amounts of oxygen during ripening do to wines?

A
  • soften tannins in red wines
  • give complexity to flavours: fruit will fade into teriary characters like earth or leather
  • colour changes. Red becomes paler and can turn brown, white becomes deeper in colour and becomes a bit orange
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Why are wines rarely kept more than 2 years in barriques?

A

Because of its small size (225 liters), the relative surface touching the oak (and thus oxigen) is very big compared to larger vessels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Why would barrels not fully be topped up? Examples

A

For fortified wines that have a deliberate oxidative style this is a technique used to create nutty, caramel and toffee flavours.

Olorosso, Tawny Port and Rutherglen Muscat

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the risk of too much oxigen exposure during ageing?

A

Too much loss of fresh fruit flavours and stale smell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is SO2 and what is it used as?

A

Sulfur Dioxide

  • antioxidant
  • antiseptic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Why is the use of SO2 restricted?

A

It can be toxic (though the concentration in wine is lower than dried fruit)

It can cause allergic reactions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is a ‘bound’?

A

SO2 when it reacts with O2. It loses its protective ability and becomes a ‘bound’

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does SO2 do, other than protect against oxigen?

A

It kills off bacteria and yeasts (except for the one that does the alcoholic fermentation)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What other use, aside from micro oxidation, do oak vessels have?

A
Adding tannin (and thus structure)
Adding flavour (like vanilla, toast, smoke and cloves)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are 4 important factors in choosing the type of oak vessel

A
  • species and origin. Oak from different species or origins can have different characteristics (flavour etc)
  • size. Small vessels have more impact than big vessels (due to relative surface contact
  • age. The amount of flavour a barrel gives to the wine deminishes with every useage
  • production. For instance toasting, which gives distinct flavours to the wine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What is a piece, and what is a barrique?

A

Piece is an oak barrel of 228 liters

Barrique is 225 liters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are the 2 main origins of oak vessels?

A

American Oak and European (French, Hungarian, Russian)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

After how many times do oak vessels lose most of their flavour?

A

After 4 uses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are other ways than oak barrels to get the aroma’s and tannins in the wine?

A

Chips or staves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are 2 ways temperature be controlled in stainless steel vessels?

A

Sleeves on the outside

Coils on the inside

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Why do some wine makers prefer concrete vessels?

A

The thick shells help to regulate temperature

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Why should damaging the seeds be avoided during crushing?

A

It releases bitter and astringent oils an tannin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

When is pressing done?

A

In white wines before fermentation, in red wines usually after fermentation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is free run juice?

A

The juice that comes from crushing, when the skin is lightly broke

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What does a traditional (basket) press look like?

A

It is vertical, with a plate that is raised or lowered by using a screw or lever. Still used in Champagne

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

How does a pneumatic press work?

A

With an inflateable tube within a horizontal cylinder, sometimes built within a closed stainless steel tank to minimize contact with oxygen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Name 3 components that can be adjusted in a wine (or must)

A

Sugar, alcohol and acid

33
Q

What is the must weight?

A

The level of sugar in the must

34
Q

What is RCGM?

A

Rectified Concentrated Grape Must, a sypury liquid, used to ‘enrich’ the grape must to get higher levels of alcohol

35
Q

When is enrichment done?

A

In cooler climates, adding RCGM, helps raise alcohol levels when grapes don’t get enough sugar on their own

36
Q

What is a danger of enrichment?

A

The wine may not have enough flavour to balance the higher levels of alcohol

37
Q

What is chaptalisation?

A

Enrichment with sources other than RCGM, for instance sugar beets

38
Q

What is another way, other than enrichment, to get more alcohol in the wine and what is the risk here?

A

Remove water from the juice. It concentrates the sugars, but also everything else (even flaws)

39
Q

Why and where is acidification done?

A

Usually only in warmer regions, where acid levels can drop too far during ripening

40
Q

How is acidification done?

A

By adding tartaric acid in powder form

41
Q

How, why and where is deacicidication done

A

Usually in colder regions, where acid levels have not dropped enough during ripening, by using alkali

42
Q

What is acoholic fermentation?

A

The conversion of sugar into alcohol and CO2

43
Q

What are the by-products (4) of alcoholic fermentation?

A

CO2
Alcohol
Heat
Flavour compounds

44
Q

What is the yeast responsible for most fermentation in wine?

A

Saccharomyces Cerevisae

45
Q

Why is Saccharomyces Cerevisae a good yeast for alcoholic fermentation?

A

Its is very resistant to alcohol and SO2

46
Q

What is the lowest temperature required for alcoholic fermentation?

A

5 *C

47
Q

When does alcoholic fermentation stop?

A

When sugar runs out

When nutrients other than sugar run out

When the temperature of the juices reaches over 35 *C

When the alchol level becomes too high (this requires a lot of sugar to begin with)

48
Q

How can the fermentation be stopped before all the sugar is consumed?

A

By adding SO2 or grape spirit to kill the yeast

Or by removing the yeast using filtration after chilling the wine below 5 *C

49
Q

Why are ambient (indiginous) yeasts not suitable for high volume wine production?

A

Winemakers cannot what yeasts exactly are present, which may result in different flavours between batches and longer fermentation times

50
Q

In what way does fermentation temperature influence the final wine?

A

Fermenting at low temperatures avoids the loss of volatile aroma’s that have a floral character and encourages the development of fruity flavours.

Higher temperatures promote extraction of colour and tannin

51
Q

What is MLF

A

Malolactic fermentation. Which takes place after alcoholic fermentation. Turning malic acids into lactic acids (which are softer to the palate)

52
Q

What is the effect of MLF?

A

It creates softer acids, reduces acidity, and creates buttery flavours.

A byproduct is also CO2

53
Q

How is MLF encouraged?

A

Raising the temperature during fermentation

54
Q

What are lees?

A

Dead yeast cells and grape fragments

55
Q

What 2 types lees are there?

A

Gross and fine

56
Q

Why would a wine maker keep the wine in contact with the lees?

A

It adds texture and flavour

57
Q

What are the components of a typical still wine?

A
Ethanol
Tannins and colour
Water
Acids
Sugars
Aroma’s and flavour compound
58
Q

Why would a winemaker store its wine for the shortest amount of time possible in an inert vessel (wine quality, not economic)

A

To keep as many primary fruit aroma’s as possible

59
Q

What does a wine need in order to survive medium to long term ageing?

A

Tannins
Acidity
and/or alcohol

And flavours that can develop in an interesting way

60
Q

When is blending most often done?

A

After fermentation or during maturation

61
Q

Why is blending done?

A

Improve balance, attain consistency and/or achieve a certain style

62
Q

Why is blending for consistancy so inportant?

A

Wines ripened in different vessels can show slight differences for a number of reasons. To get one consistant product in all of the bottles, the wines are often blended.

Differences can arise due to variations in the oak, vineyard site or harvesting time.

63
Q

What can winemakers do to create as many blending options as possible? (6)

A

Seperate press fractions
Fermenting or maturing in different types of vessels
Only allowing a portion of the wine to go through MLF
Using different varieties
Vinyard plots
Vintages

64
Q

What are the 3 main techniques for clarification?

A

Sedimentation
Fining
Filtration

65
Q

Why would a winemaker NOT clarify its wine?

A

If they believe it can harm the character of the wine

66
Q

What is sedimentation and racking?

A

When winemakers let gravity pull suspended particles (such as gross lees) to the bottom of the liquid and then pump the clear liquid off of the sediment. This is called racking, and can be done at multiple moments and stages (all after fermentation).

67
Q

What is fining?

A

The process of speeding up the clumping together of certain constituents, in order to filter them out as a part of clarifying the wine.

68
Q

What are the 2 types of filtration?

A

Depth filtration - the wine is passed through thick layers of material

Surface filtration - using very fine sieves. Sometimes so fine that it can be called sterile filtration

69
Q

When is a wine considered stable?

A

If it changes in a slow, predictable manner over a specified time frame

70
Q

Apart from clarification, what are 3 important areas that require stabilisation?

A

Tartrate stability, microbiological stability and oxygen stability.

71
Q

What are tartrates?

A

It is cristalized tartaric acid. They are harmless and flavourless.

Cold temperatures speed up the process of cristalization. (This fact can be used by winemakers to force tartrate stability)

72
Q

What aids microbiological stability?

A

Alcohol, lack of nutrients and acidity.

73
Q

Name 2 styles that are naturally resistant to microbiological spoilage

A

Fortifies wines - because of the high alcohol levels

Dry, high acid, MLF wines - alcohol, lack of nutrients and acidity.

74
Q

What are 2 ways to sterilize a wine?

A

SO2 and sterile filtering

75
Q

What happens to wine if a wine is exposed to oxygen (during or) after bottleing?

A

Losing fresh fruit aroma’s and turning brown

76
Q

Why is wine mostly packaged glass bottles?

A

Cheap, sturdy and portable. And completely airtight (the glass itself)

77
Q

What is the downside to using glass bottles?

A

Heavy and rigid. Which adds transport costs and takes op much space.

78
Q

Why is plastic not the beet option for storing wine?

A

Tiny amounts of oxigen pass through, which puts the wine at risk within about 18 months. So it is good for early drinking wines, but nothing that needs ageing.