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CSW Study Guide > Ch. 5: Fermentation & Still Wine Production > Flashcards

Ch. 5: Fermentation & Still Wine Production Flashcards

1
Q

Pre-Fermentation

A

Priority to begin the winemaking process as soon as possible after harvest

Winemaker keeps grapes cool and covered

May use sulfur as a preservative while grapes en route to facility

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2
Q

Sulfur in wine making process

A

Can be added to grapes or juice at any of several points

Combines with O2 to form Sulfur Dioxide (SO2)

SO2 inhibits growth of both yeast and bacteria

Reduces likelihood of premature fermentation and spoilage

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3
Q

The Crush

A

Pre-fermentation nickname

Actual crushing of the grapes

Also everything that gets the juice ready for the initiation of fermentation

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4
Q

Sorting

A

First stop for grapes – sorting table

Leaves, underripe grapes, damaged fruit, other debris removed

Rigorous selection – high production costs, reserved for high-end wines

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5
Q

Crushing and Destemming

A

Grapes sent through crusher or crusher/destemmer

If destemming, grapes simultaneously separated from stem of the bunch

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6
Q

Difference between crushing and pressing

A

Pressing – skins of grapes are broken and juice is allowed to flow, but no pressure applied

Crushing must be done gently

Too much force can cause release of tannins from skins and seeds

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7
Q

Pressing

A

In white winemaking, contact between skins and juice is minimized

Grapes can go through up to three pressings

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8
Q

Pressing - Cold Soak

A

More aromatic grape varieties that benefit from skin contact are allowed to macerate with juice for no more than 24 hours

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9
Q

Free run juice (Press juice)

A

Movement of grapes from harvest causes many berries to burst open

Large amount of juice drains from the press immediately

Considered to be the highest quality

Rich in sugar and low in tannin

May be made into winery’s best wines

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10
Q

Bladder press

A

Modern presses

Inflate a large balloon with air or water to squeeze the grapes

More flexibility

Less likely to crush seeds or burst open skin cells

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11
Q

Pomace

A

Cake of dry, compressed skins and seeds that remain after final pressing

Composted

Made to make pormace brandies

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12
Q

Pomace brandies

A

Marc

Grappa

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13
Q

Must

A

Grape juice that’s destined for fermentation

May move to fermentation immediately or winemaker may make adjustments

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14
Q

Must Adjustments

A

Acidification

De-acidification

Enrichment

Chaptalization

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15
Q

Acidification

A

Addition of acid to the must

Addresses the issue of low acidity

Done with tartaric acid

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16
Q

De-acidification

A

Achieved through potassium or calcium bicarbonate

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17
Q

Enrichment

A

Addresses issue of insufficient sugar

Blending with grape juice or concentrated grape sugar

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18
Q

Chaptalization

A

Sugar cautiously added to must before fermentation begins

Only enough sugar to achieve acceptable alcohol level in finished wine

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19
Q

Other Must Adjustments

A

Raising or lowering the concentration of sugar

Adding or removing water

Procedures are highly regulated in many parts of the world

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20
Q

Debourbage

A

Winemaker lets the juice settle for a day or two before allowing fermentation

Must be done to:

Let must adjustment fully integrate with juice

Wait for some of the solids to settle out of the solution – less sediment

Have time to process more grapes that will go into the same batch

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21
Q

Fermentation

A

Complex biochemical process

Involves thirty successive chemical reactions catalyzed by a specific enzyme in the yeast

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22
Q

Fermentation Process

A

Yeast cells attack sugar molecules

Break them apart to release energy

Smaller molecules that remain after yeast cells have split apart the sugar that are ethyl alcohol and CO2

After yeast worked its way through must in tank, virtually all fermentable sugar is replaced by alcohol and CO2

CO2 mostly dissipates in the air

Must has become wine

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23
Q

Basic Fermentation Chemical Formula

A

C6H12O6 + yeast –> 2(C2H5OH) + 2 (CO2) + heat

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24
Q

Sugar During Fermentation

A

90% of grape sugars fully converted to ethanol and CO2

Rest broken down into:

Glycerol
Succinic acid
Acetic acid
Lactic acid
Acetaldehyde
Ethyl acetate
Other alcohols (methanol)

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25
Q

Stainless Steel Fermentation

A

White wines often fermented in SS tanks

Inert – does not impact flavors of the wine

Airtight, easy to clean, easy temp control

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26
Q

Barrel Fermentation

A

Some white wines are barrel-fermented to add complexity

Introduce oak flavors and downplay fruit aromas

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27
Q

Other Fermentation Vessels

A

Wooden casks

Concrete vats

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28
Q

Initiating Fermentation

A

Yeast cells and spores found in and around wineries

Brought into the winery on harvested grapes

Remain in the winery from previous year’s fermentation

As soon as sugar rich juice is released from grapes, yeast cells jump in and begin feasting and multiplying

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29
Q

Preventing Fermentation

A

Sulfur added

Must may also be refrigerated

Prevents fermentation from happening too soon or with unwanted strains of yeast

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30
Q

Natural Fermentation

A

Use of native yeast cells

Can be effective and deliberate winemaking technique

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31
Q

Inoculation

A

Addition of must with commercially grown yeast

Gets fermentation off to fast start

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32
Q

Usage of Other Yeasts

A

Saccharomyces cerevisiae most common

Different strains used to add desirable flavors or aromas

To speed up or slow down fermentation

To achieve certain level of alcoholic strength

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33
Q

During Fermentation

A

As yeast cells multiply, must bubbles and foams

CO2 escapes

Grows warm

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34
Q

Fermentation – Best Temps for White Wines

A

Between 50 and 60 degrees

Best for retaining delicate fruit and floral aromas

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35
Q

Effects of High Temps During Fermentation

A

As temp increases, yeast cells become more active

Sugars converted to alcohol at faster pace

Fresh fruit and floral elements can disappear

Introduces cooked fruit aroma

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36
Q

Stuck Fermentation

A

If fermentation gets out of control

Liquid gets above 100 degrees

Yeast will likely die, fermentation will stop prematurely

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37
Q

Temperature Control During Fermentation

A

One of the most important things the winemaker does

Refrigerated jackets, coils, or panels

Before that, fall weather conditions and underground wine cellars

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38
Q

End of Fermentation

A

Fermentation is over when sugar is depleted and nothing left for yeast to consume

Can take several days to several weeks

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39
Q

When Alcohol Level Reaches More Than 14%…

A

Yeast can no longer survive

Residual sugar

Winemaker may stop fermentation when wine is intended to be off-dry or medium dry (fortified/dessert wines)

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40
Q

Malolactic Fermentation (Secondary Fermentation)

A

Conversion process that can take place simultaneously with primary fermentation

Strain of lactic acid bacteria decomposes malic acid in wine and converts it to lactic acid

Tart, apple characteristic of malic acid becomes milder and creamier

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41
Q

Diacetyl

A

Ester created as a by product of MLF

Imparts buttery aroma to wine

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42
Q

Wines that Benefit from MLF

A

Chardonnay

Chenin Blanc

Viognier

Have notes of butter, hazelnut, brioche, and dried fruit

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43
Q

Lees

A

Expired yeast cells and other solid particles in wine that sink to the bottom of tank/barrel

Wine is quickly removed from lees

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44
Q

Sur Lie Aging

A

“On the lees”

Wine is allowed to rest in contact with lees for extended period of time

Dead yeast cells decompose

Impart yeasty aroma, creamy texture, more complexity

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45
Q

Lees Stirring (Batonnage)

A

Lees is stirred back into the liquid

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46
Q

Sulfur Addition

A

After fermentation, sulfur level is typically checked again

Addition might be necessary to decrease chance of microbial spoilage or browning

Important if there’s residual sugar – can lead to fermentation after bottling

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47
Q

Clarification

A

New wine has cloudy appearance

Due to remaining yeast cells & other solids

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48
Q

Clarification Methods

A

Racking

Fining

Filtering

Centrifuge

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49
Q

Racking

A

Uses gravity

Allows suspended matter to settle to bottom of vessel

Wine drawn off the sediment and moved to fresh container

Several rackings might take place

Some tannins or proteins will remain in solution

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50
Q

Fining

A

Inert material stirred into wine

Attracts unwanted sediment

Separated from wine by racking

Gelatin, egg whites, bentonite clay

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51
Q

Filtering

A

Straining the wine through a barrier with very fine openings

Can eliminate contaminants that can cause spoilage – sterile filtering

Filtering carefully monitored as it could reduce desirable flavor molecules

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52
Q

Centrifuge

A

Laboratory equipment

Uses accelerated gravity to separate wine from heavier solids

53
Q

Barrel Aging

A

Oak barrels allow for slow oxidation

Adds complexity

Chardonnay and Sav Blanc can benefit

54
Q

Barrel Aging – New Wood

A

Can add:

Vanilla

Oak

Wood

Coconut

Toast

55
Q

Blending

A

Different vats of wine may be blended together

Important for branded wines – need to recreate flavor profile consistently

Develops complexity/balance to create particular style of wine

56
Q

Cold Stabilization

A

Chilling wine around 25 degrees

1 to 3 weeks

Then rack wine off the precipitates

57
Q

Alternative to Cold Stabilization

A

Use of finely ground bis of potassium bitartrate

Initiate formation of tartrate crystals, after which may be filtered

58
Q

Bottling

A

Last task

Bottling line receives bottles at one end

Fills them

Seals with cork

Installs capsule over neck

Labels them

Packages in boxes

Stored for shipment/sale

59
Q

Crushing and Destemming – Red Wine

A

Required in red grapes

Skins used during fermentation process

Destemming can be done

Stems may be added back to provide additional tannin, flavor, complexity

60
Q

Must Adjustment

A

Winemaker might adjust acidity or sugar levels or add tannin

Leaving stems in must or adding tannin powder

61
Q

Maceration

A

Period of contact btw skins and juice

As skins remain in contact with juice, red/blue pigments are extracted from skins, along with tannins and flavor constituents

Few days to few weeks, longer

One of the winemakers most important decisions

62
Q

Maceration – Longer vs Shorter Periods

A

Longer = Deeply colored, highly tannic, bursting w/ flavor, and need time to mature

Shorter = Softer, more accessible wines, ready to consume upon release

63
Q

Maceration – Longer Period Examples (Wines)

A

Syrah

Cab Sav

64
Q

Maceration – Shorter Period Examples (Wines)

A

Pinot Noir

65
Q

Cold Soak

A

Winemaker chooses to begin maceration before fermentation

Must is chilled to below 55 degrees to postpone fermentation

Allows winemaker to control level of phenolics

66
Q

Fermentation – Difference BTW White and Red Wines

A

Main difference – skins in must

Needs to be maintained during fermentation

Impacts selection of vessels, favoring use of large tanks over small wooden barrels

67
Q

The “Cap”

A

CO2 produced during fermentation forms bubbles

Bubbles push grape solids to top of vessel

Solids = “Cap”

68
Q

Cap Management

A

Extraction of phenolics requires skins to be in liquid, not on top

Acetobacter might grow on the cap

Might cause excess acetic acid

Trapped CO2 might cause cap to burst

69
Q

Cap Management Methods

A

Punching down

Pumping over

Rack and return

Rotofermentation

70
Q

Punching Down

A

Pushing cap into juice

Fench = Pigeage

71
Q

Pumping Over

A

Pumping juice from bottom of tank and spraying it over top of the cap

French = Remontage

72
Q

Rack and Return

A

Draining fermenting juice into separate tank before it’s returned to original tank by spraying it over now sunken cap

Considerably more aeration

French = Delestage

73
Q

Rotofermentation

A

Agitating the fermenting must in specialized fermentation vessel

Vessel either rotates on its own or contains inner paddle that mixes

Usually controlled by computer

74
Q

Fermentation Temperature – Red Wine

A

Higher than whites

Allows for increased extraction of phenolics

60 to 70 degrees for light Pinot Noir

85 to 95 degrees for Cab Sav

75
Q

Extended Maceration

A

Skin is allowed to stay in contact with must for several days to several weeks

When fullest extraction of phenolics is desired

76
Q

Malolactic Fermentation – Red Wines

A

Often spontaneous

Might be initiated with inoculation of lactic acid-producing bacteria

Done between beginning of fermentation and transfer into barrel

77
Q

Pressing – Red Wine

A

Remaining solids pressed to release any remaining wine

Very rich in tannin and color – might be added to long-run wine or used in separate blend

78
Q

Clarification – Red Wine

A

After pressing, wine might be moved to tank for clarification

One or more rackings likely performed

Might be filtered

79
Q

Oak Aging – Red Wine

A

Can be beneficial

Especially for wines high in tannin

Use of young barrels add vanilla, toast, woodsy aromas

Many mid- and upper-range red wines spend some time in barrels

80
Q

Polymerization

A

Slow infusion of O2 that seeps through wood into wine

Helps tannin molecules combine with each other

Tannins feel softer & richer

81
Q

Variations in Oak Barrels – New Barrels

A

Impart significant flavor

Less oak flavor after each year

Most flavor leached out after four years

82
Q

Variations in Oak Barrels – Larger Barrels

A

Have less effect than small barrels

83
Q

Variations in Oak Barrels – French vs US

A

French oak = More subtle and refined in flavor

American oak = more assertive, less expensive

84
Q

Variations in Oak Barrels – Handmade Over Open Fire

A

Bent into shape

Imparts toast or charring on wood

85
Q

Barrel Choice

A

Winemakers choose shape, size, type of wood

Light, medium, or heavy toast

French oak barrique – high end wines

86
Q

Micro-Oxygenation

A

Bubbling tiny amount of O2 into wine to simulate oxidation effects of barrel aging

87
Q

Carbonic Maceration

A

Enzymatic fermentation

Doesn’t require yeast or bacteria

Whole, unbroken grapes placed in enclosed fermentation vessel

Blanketed with CO2

Enzymes break down grape sugars & create alcohol within berries

100% CM is rare

Breakage in grapes lead to yeast introduced in juice

Used in initial stages of wine production

Remaining sugar converted by normal fermentation

Primarily known for use in Beaujolais/Beaujolais Nouveau

88
Q

Carbonic Maceration – Red Wines

A

Low in tannin, brightly colored

Tropical fruit and red berry aromas/flavors

89
Q

Rose Wine

A

Pale pink

Dusty rose

Orange-tinged (salmon/onion skinned)

90
Q

Rose Wine Styles

A

Still

Sparkling

Dry

Off-dry

Sweet

91
Q

Color of Rose Wine

A

Determined by grape type

Amount of time spent in skin

Most common – juice sits with skins from few hours to several days

Juice is pressed off, fermentation continues

92
Q

Alternative Methods of Rose Wine Production

A

Fermenting white grapes with red grapes

Blending small amount of red wine with white wine

93
Q

Rose Wine – Saigniee Method

A

Produces both rose wine and concentrated red wine from same grapes

Red grapes crushed, destemmed, vatted from 2-20 hours

Certain amount of juice is run off to make rose

Remaining juice stays with skins to make red wine

94
Q

Rose Wines – Direct Press Method

A

Pale roses (vin gris)

Grapes, destemmed or whole cluster

Crushed immediately after harvest

Juice is pressed

Short period of maceration

Resulting pale pink juice is fermented

95
Q

Roses Should Always Be…

A

Fruity

Refreshing

Med to high acidity

96
Q

Blush Roses

A

Slightly sweet

White Zin

97
Q

Rose Wines – Other Terms

A

Rosado – Spain

Weissherbst – Germany

Rosato – Italy

98
Q

Traditional View of Winemaking

A

Natural aspects of vineyard and production facility are paramount

Wine should reflect physical environment as much as possible

99
Q

Alternative View of Winemaking

A

Grapes are raw materials to be molded into desired form by human artistry, expertise, and technology

100
Q

Winemaker’s Most Active Time

A

Just before harvest through end of fermentation process

Remainder of year is slower pace

101
Q

Non-Harvest Activities for Winemaker

A

Checks on progress of aging wines

Decides when to bottle

Plans for next vintage

102
Q

Flying Winemakers

A

Winemakers who travel between northern and southern hemispheres to make wine twice a year

103
Q

Sweet Winemaking Practices

A

Botrytis

Late Harvest

Dried Grapes

Freezing

104
Q

Botrytis – Sweet Wine

A

Fungus affects the grapes at the right time

Causes water to evaporate from berries

Raises concentration of Sugar

105
Q

Regions Known For Botrytis Sweet Winemaking

A

Sauternes area of Bordeaux

Loire Valley

106
Q

Grapes Used in Botrytis Sweet Wines

A

Chenin Blanc

Semillon

107
Q

Botrytis Aromas

A

Honeysuckle

Apricot

108
Q

Late Harvest

A

Berries continue to gain sugar as long as there are leaves on vine

Begin to lose water

Lose acidity

109
Q

Regions Known for Late Harvest Sweet Winemaking

A

Cool climates

110
Q

Grapes Used in Late Harvest Sweet Wines

A

Chenin Blanc

Riesling

111
Q

Winemaking - Dried Grapes

A

After harvest

Grapes allowed to dry and become partially raisinated

Dried grapes may be fermented into dry, high alcohol wines

Amarone – Italy

112
Q

Freezing

A

Growers may leave grapes on vine until weather turns cold enough to freeze them

As late as Jan/Feb in Northern Hemisphere

Significant sugar content developed

Pressed immediately

113
Q

White Grapes Used in Freezing Sweet Winemaking

A

Riesling

Gwertz

Chenin Blanc

114
Q

Eiswein

A

Ice wine

115
Q

Red Grapes Used in Freezing Sweet Winemaking

A

Cab Franc

116
Q

Cryoextraction

A

Mechanical freezing process

117
Q

Procedures for Making Sweet Wines

A

Refrigeration

Adding sweetness

Fortification

Killing yeast via pasteurization

Adding large amounts of sulfur

118
Q

Sweet Wine Procedure – Refrigeration

A

Chilling must during fermentation

Stops yeast activity while there is sugar left

Sterile filtering or sulfur added to make sure wine doesn’t begin fermenting after bottling

119
Q

Sweet Wine Procedure – Adding Sweetness

A

Wine allowed to ferment dry

Addition of sugar, grape concentrate, or unfermented juice

Risk of restarting fermentation unless protective measures used

120
Q

Sweet Wine Procedure – Fortification

A

Adding distilled spirits during fermentation

Kills yeast before all sugar is gone

121
Q

US Certified Organic Wines

A

Dept of Agriculture National Organic Program (DOANOP)

Wines made from minimum of 95% certified organic grapes

Nothing used that’s prohibited by NOP

Display USDA Organic Seal

122
Q

Most Significant Restriction in Organic Winemaking – US

A

Use of sulfur

Wines can be labeled organic if made from certified organic grapes and sulfur dioxide yields less than 100 parts per million

123
Q

EU Organic Wines

A

Vin Biologique

Must contain 30-50% less added sulfur than non-organic wines

No additives permitted

Winemaking process must be fully traceable

124
Q

Biodynamic Wines

A

100% biodynamically grown grapes

Minimal manipulation and low impact on environment

125
Q

Biodynamic Wine Certification

A

Based more on progress toward an extensive list of goals than strict criteria

Genetically modified materials prohibited

Sulfur use kept to minimum

126
Q

Biodynamic Governance

A

Private org

Demeter International

127
Q

Kosher Wines

A

Certified by Jewish religious authorities to conform to biblical law

For consumption of observant Jews

Can be made from any grapes

Materials can only be handled by observant male Orthodox Jews under supervision of a rabbi

Animal based products can’t be used

128
Q

Mevushal Wine

A

Subcategory of kosher wine

Free from limitations on who may handle it

Briefly subjected to high heat before leaving winery

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