1
Q
Describe the process of alcoholic fermentation.
A
The metabolism of yeast cells converts sugar in grape must into ethyl alcohol (ethanol) and carbon dioxide (CO2)
2
Q
Name 3 volatile compounds that can be found in wine.
A
Acetaldehydes
Ethyl acetate
Fusel oils
3
Q
What is the importance of sulfur dioxide (SO2) in winemaking?
A
Prevents oxidation and bacterial contamination; ensures rapid fermentation
4
Q
How can acetaldehyde be defined in a finished wine?
A
Oxidation
5
Q
What happens when acetaldehydes react with alcohol in a finished wine?
A
Produces ethyl acetate – volatile acidity
6
Q
What is acetobacter?
A
The group of bacteria responsible for turning wine into vinegar in the presence of oxygen
7
Q
How does hydrogen sulfide (H2S) present itself in a wine?
A
Rotten eggs
8
Q
When do hydrogen sulfide (H2S) compounds form?
A
When there are low levels of nitrogen in the must
9
Q
Which chemical compound do sulfites refer to?
A
Sulfur dioxide (SO2)
10
Q
Which chemical compound do sulfides refer to?
A
Hydrogen Sulfide (H2S)
11
Q
At what low temperature will yeast not begin fermentation?
A
Below 50˚ F
12
Q
At what temperature will yeasts die?
A
Above 105˚ F
13
Q
Do white wine fermentations run cooler or hotter?
A
Cooler
14
Q
What flavors get preserved in a cooler fermentation?
A
Fruit
Freshness
15
Q
Do red wine fermentations run cooler or hotter?
A
Hotter – can reach the 90˚ F
16
Q
What are the risks of performing a hotter fermentation?
A
Volatilized (lost) flavor compounds
Stuck fermentations – past 95˚ F
17
Q
What are some benefits of a hot fermentation?
A
Increased extraction of color, tannin and flavor compounds
18
Q
What is a stuck fermentation?
A
A disastrous and sudden shutdown of yeast activity
19
Q
Name 3 reasons why a stuck fermentation might occur.
A
Challenging vintage
Yeast nutrition has been difficult to manage
The winemaker used ambient yeasts to ferment
20
Q
What is bâtonnage?
A
Lees stirring
21
Q
How does bâtonnage impact a wine?
A
Adds further complexity and richness
22
Q
What is the volume of a barrique?
A
225 L
23
Q
What is the volume of a tonneau?
A
900 L (no longer used)
24
Q
What is the volume of a pièce used in Burgundy?
A
228 L
25
What is the volume of a feuillette used in Chablis?
132 L
26
What is the volume of a feuillette used in the Côte d’ Or?
114 L
27
What is the volume of a Quartaut?
57 L
28
What winemaking region are quartaut barrels used?
Burgundy – Côte d’ Or
29
What is the volume of a barrel used in Cognac?
350 L (modern size)
30
What is the volume of a pièce used in Armagnac?
400 – 420 L
31
What is the volume of a barrel used in Champagne?
205 L
32
What is the volume of a demi – muid used in the Southern Rhône Valley?
600 L
33
What is the volume of a foudre used in Alsace?
Variable
34
What is the volume of a fuder used in the Mosel?
1000 L
35
What is the volume of a stuck used in the Rheingau?
1200 L
36
What is the volume of a butt in Jerez?
600 – 650 L
37
What is the volume of a bota chica (shipping butt) in Jerez?
500 L
38
What is the volume of a pipe used in Douro/ Porto?
550 – 630 L (production and aging)
534.24 L (shipping)
39
What is the volume of a pipe used in Madeira?
418 L (shipping)
40
What is the volume of a pipe used in Marsala?
423 L (shipping)
41
What is the volume of a botte used in Italy?
Variable
42
What is the volume of a caratelli used in Italian Vin Santo production?
50 – 225 L
43
What is the volume of a tino used in Italy?
Large vertical cask – variable
44
What is the volume of a tonneau used in Italy?
550 L
45
What is the volume of a gönc used in Tokaj?
Approx. 136 L
46
What is the volume of an American Oak Whiskey Barrel?
190 L
47
What is the volume of a hogshead in Australia?
300 L
48
What is the volume of a puncheon in Australia?
450 – 500 L
49
Name 2 advantages to using cultures yeasts in the fermentation process.
Promise reliability
Can work in higher levels of alcohol than ambient yeasts
50
What is chaptalization?
The addition of sugar to the must
51
What does chaptalization used for?
To increase the final alcohol and glycerin content of the wine
52
What is reverse osmosis?
An alcohol adjustment technique
53
How does reverse osmosis work?
Separates the wine into 2 constituent parts: permeate and retentate.
Permeate (water and ethanol) is distilled to a proper level and recombined with the retentate (wines aromatic compounds)
54
What is acidification?
The addition of acid to must or a finished wine
55
Name 2 acids that may be used for acidification.
Tartaric acid (added prior to fermentation is preferred)
Malic acid
56
What is malolactic fermentation?
Harsh malic acid is converted to softer lactic acid and carbon dioxide
57
When can malolactic fermentation occur?
During or after alcoholic fermentation
58
What compound is a byproduct of malolactic fermentation?
Diacetyl
59
What aromas is diacetyl responsible for?
Buttery aromas
60
What is carbonic maceration?
Whole, uncrushed grapes in an anaerobic environment (under a protective blanket of CO2) initiate an intracellular fermentation.
Occurs without the action of yeasts.
Must be combined with a standard fermentation.
61
What 2 grapes is whole cluster fermentation common?
Pinot Noir
Syrah
62
Name 2 advantages to using stems in winemaking.
Spicy aromatic complexity
Structure
63
Name a potential hazard to using damaged or underripe stems.
Can cause undesirable green flavors
64
What does pre fermentation maceration do?
Promotes the extraction of color and tannin
65
What is cold soaking?
Red grape must is held at low temperature (close to 0˚ C) prior to fermentation, typically for 2 to 10 days
66
When does cold soaking occur?
Pre fermentation
67
What is pigeage?
A traditional method of submerging and breaking up the cap
68
What is another name for pigeage?
Punching down
69
How can pigeage be performed?
Poles
Paddles
Feet
Mechanically
70
What is remontage?
Fermenting wine is pumped over the top of the cap
71
What is the French term for cap?
Chapeau
72
What is a chapeau?
Cap
73
What does a cap refer to in red wine making?
Grape solids that develop on the surface of the must, pushed up by C02
74
What happens to the cap if there is no intervention during red wine making?
The cap will dry out, solidify and prevent extraction
75
Describe the process of délestage.
The fermentation vessel is fully drained; the wine is racked into a separate vessel while the cap drains fully and is then pumped back over the cap in the original fermentation vessel
76
What is vin de goutte?
Free run wine
77
What is the French term for free run wine?
Vin de goutte
78
What is vin de presse?
Tannic press wine
79
How can vin de presse impact a finished wine?
May be blended into a finished wine to add structure
80
How does a traditional basket press work?
Relies on vertical pressure to press the pomace
81
How does a pneumatic bladder press work?
Exerts a gentle pressure on the grapes by means of its inflation with air
82
What does élevage mean?
Maturation period
83
What is the French term for racking?
Soutirage
84
What is the English term for soutirage?
Racking
85
What is racking?
The movement of wine from one vessel to another providing aeration and clarification as the wine is removed from its lees or sediment
86
What is the French term for fining?
Collage
87
What is the English term for collage?
Fining
88
What is fining?
Requires a fining agent to precipitate solids out of the wine
89
Name 5 commonly used fining agents.
Bentonite
Casein
Isinglass
Gelatin
Egg white
90
What is filtration?
More invasive and expensive; clarifying a wine through pads or a membrane with microscopic openings
91
At what point in the winemaking process are white grapes crushed and pressed?
Prior to fermentation
92
How can maceration of white grape skins affect a wine?
Enables the extraction of aromatic compounds
93
How can maceration of white grape skins negatively affect a wine?
Can lead to excessive tannin and bitterness if unchecked
94
What is débourbage?
Settling
95
What is the process of debourbage?
Allows the juice to be racked off suspended solids and clarified prior to fermentation
96
What is cold stabilization?
A process that causes tartrate crystals to precipitate out of the wine
97
At what temperature is cold stabilization achieved?
25˚ F
98
What is süssreserve in Germany? What is the sweetening agent?
Sweetness may be added back to a wine after it ferments to dryness
## Footnote
Sterilized fresh grape juice
99
What wines will undergo full or partial malolactic fermentation?
White wines matured in oak
100
How can malolactic fermentation impact a white wine?
Supplement richness and body
101
What is bâttonage?
Stirring of the dead yeast cells
102
Name the 2 basic methods of rosé winemaking.
Blending
## Footnote
Limited skin maceration
103
What is blended rosé?
The product of red and white wines blended together
104
Describe the limited skin maceration technique for rosé winemaking.
Juice is intentionally kept in contact with its skins for a period of several hours to several days
105
What is the French term for 'bleeding'?
Saignée
106
What is saignée?
Bleeding
107
What is the saignée method?
Pink juice is drawn from a vessel to concentrate the remaining must for red wine production
108
What is direct pressing?
The direct pressing of whole red grapes or clusters
109
What color is common for direct pressed rosés?
Pale pink
110
Describe oak wood.
Water tight
Lightweight
Malleable wood
111
How does oak affect a wine?
Allows gentle, slow oxidation to occur, rounding out and softening the texture of wine
112
Describe the contributions new oak can have on a wine.
Lactones
## Footnote
Phenolic aldehydes (vanillin)
## Footnote
Wood tannin
113
What is the range in which oak becomes neutral?
4 to 6 years
114
Name 3 cheaper alternatives to using an oak barrel. What component do the wines lack when these are used?
Oak chips
## Footnote
Staves
## Footnote
Powder
## Footnote
Does not provide an oxidative effect
115
What is the French term for micro-oxygenation?
Microbullage
116
What is the microbullage?
An aeration technique in which small amounts of oxygen are allowed to enter a stainless steel tank during, either fermentation or maturation
117
How does a barrel impart flavor on a wine?
Toast level and the type of wood
118
Name the 2 types of oak trees used for French oak. Describe them.
Quercus robur
## Footnote
Quercus petraea
## Footnote
Tight wood grain developed through slow growth
119
Name the oak tree used for American oak. Describe it.
Quercus alba (American white oak)
## Footnote
Wider grain
120
How is French oak processed to make a stave? How does this affect the barrel?
Split wood
## Footnote
Prevents leakage in the final barrel
121
How is American oak processed to make a stave?
Sawn
## Footnote
Releases more vanillin and lactones, resulting in a coconut character
122
How is French oak dried? How does that affect the barrel?
Air dried
## Footnote
Leaches out some of the oak's more aggressive tannins and flavors
123
How is American oak dried? How does that affect the barrel?
Kiln dried
## Footnote
Concentrates lactones
124
What are the 3 stages of heating oak staves?
Warming (chauffage)
## Footnote
Shaping (cintrage)
## Footnote
Toasting (bousinage)
125
What level of toasting promotes the most extraction of wood tannin?
Light toast
126
How can excess water affect a grape?
Delayed ripening
## Footnote
Larger berries
## Footnote
Diluted fruit
127
What are the 2 main grape sugars?
Glucose
## Footnote
Fructose
128
What device is used to measure sugar content in the field?
Refractometer
129
How does a refractometer work?
Measures the refractive index of a liquid
130
How does acidity affect a wine?
Taste
## Footnote
Color
## Footnote
Ageability
## Footnote
Microbial stability
131
What is the primary organic acid that is naturally found in grapes?
Tartaric acid
132
Name 2 ways that acidity is measured.
pH
## Footnote
Titratable acid
133
What is the general pH of wine?
Between 3 and 4
134
What is pH?
A measure of the concentration of hydrogen ions (or protons) in a solution
135
What is titratable acid?
A measure of the amount of acid (protons or hydrogen ions) available to react with a strong base through titration to a defined endpoint
136
What are phenolics?
A class of compounds that lend color, flavor and texture to wine
137
Name 2 examples of phenolics.
Tannins
## Footnote
Anthocyanins
138
What 3 categories are phenolic compounds typically divided into?
Flavonoids
## Footnote
Non Flavonoids
## Footnote
Tannins
139
What are flavonoids?
Polyphenols that contain a very specific 3 ring chemical structure
140
What are non flavonoids?
An assortment of small phenolic compounds
141
Name the 2 types of tannins.
Condensed tannins
## Footnote
Hydrolysable tannins
142
What are condensed tannins?
Polymers of flavonoids that are extracted from grapes
143
What are hydrolysable tannins?
Derived from oak
## Footnote
Comprised of non flavonoids
144
Name 3 subgroups of nonflavonoids.
Hydroxycinnamates
## Footnote
Benzoic acids
## Footnote
Stilbenes
145
How are flavonoids extracted?
Through skin contact and maceration
146
Name 3 subgroups of flavonoids.
Anthocyanins
## Footnote
Catechins
## Footnote
Other polyphenols located in grape skins, seeds, stems
147
What are anthocyanins?
A family of pigmented compounds responsible for the vibrant color of young red wine
148
At what point does the extraction of anthocyanins begin?
As soon as the berries are crushed when anthocyanins immediately start binding with tannins and other compounds to create more stable pigments
149
What are catechins?
Small polyphenols that are extracted mostly from seeds and stems (also from skins)
## Footnote
Largely responsible for bitterness in wine
150
What are tannins?
Large molecules that impart astringency and bitterness in wine
151
Describe the flavors associated with monoterpenes.
Floral
## Footnote
Citrus
## Footnote
Tree aromas
152
Name 3 terpenic grape varieties.
Muscat
## Footnote
Gewürztraminer
## Footnote
Viognier
153
What factor assists in concentrating monoterpenes in grapes?
Sunlight exposure
154
Classify and Describe Impact Flavors: Cis-rose oxide
Monoterpene
## Footnote
Rose, lychee
155
Classify and Describe Impact Flavors: Linalool
Monoterpene
## Footnote
Spicy, floral
156
Classify and Describe Impact Flavors: Geraniol
Monoterpene
## Footnote
Geranium leaf, lemon
157
Classify and Describe Impact Flavors: Citronellol
Monoterpene
## Footnote
Citronella
158
Classify and Describe Impact Flavors: Eucalyptol
Monoterpene
## Footnote
Eucalyptus, fresh, mint
159
Classify and Describe Impact Flavors: Nerol
Monoterpene
## Footnote
Rose, ginger, peach
160
Classify and Describe Impact Flavors: Camphor
Monoterpene
## Footnote
Earthy
161
Classify and Describe Impact Flavors: Pinene
Monoterpene
## Footnote
Pine
162
Where are sesquiterpenes found in the grape?
Skins
## Footnote
Stems
## Footnote
Leaves
163
What is the relationship between rotundone levels and heat?
Rotundone levels diminish in warm, sunny climates
164
Name 6 grape varieties that have elevated rotundone levels.
Syrah
## Footnote
Cabernet Sauvignon
## Footnote
Mourvèdre
## Footnote
Vespolina
## Footnote
Schiopettino
## Footnote
Gruner Veltliner
165
Classify and Describe Impact Flavors: Rotundone
Sesquiterpene
## Footnote
Black pepper
166
Classify and Describe Impact Flavors: Nerolidol
Sesquiterpene
## Footnote
Floral, apple, green
167
Classify and Describe Impact Flavors: Farnesol
Sesquiterpene
## Footnote
Floral, rose
168
What are Norisoprenoids?
Aromatically diverse set of compounds
## Footnote
Not very potent
169
Classify and Describe Impact Flavors: Trimethyl Dihydronapthalene or TDN
Norisoprenoid
## Footnote
Kerosene, petrol
170
Classify and Describe Impact Flavors: b-Damascenone
Norisoprenoid
## Footnote
Increases aromas of other compounds
171
Classify and Describe Impact Flavors: b-Ionone
Norisoprenoid
## Footnote
Violet, raspberry
172
Classify and Describe Impact Flavors: Vitispirane
Norisoprenoids
## Footnote
Eucalyptus, camphor
173
What flavor do pyrazines give off?
Potent vegetal flavors
174
Where can pyrazines be found?
Grapes
## Footnote
Stems
175
What is the relationship between pyrazines and ripeness?
More ripeness decreases pyrazines
176
Name a winemaking method that can mask the flavor of pyrazines in a wine.
Oak aging
177
Classify and Describe Impact Flavors: 3-Isobutyl-2-methoxypyrazine (IBMP)
Pyrazine
## Footnote
Bell pepper
178
Classify and Describe Impact Flavors: 3-Isopropyl-3-methoxypyrazine (IPMP)
Pyrazine
## Footnote
Green, asparagus, earth, rancid peanut butter
179
What flavors do varietal thiols impart in a wine?
Potent tropical fruit flavors
180
Classify and Describe Impact Flavors: 3-Mercaptohexyl acetate (3MHA)
Varietal Thiols
## Footnote
Passionfruit, box tree
181
Classify and Describe Impact Flavors: 3-Mercaptohexanol (3MH)
Varietal Thiols
## Footnote
Grapefruit, passionfruit
182
Classify and Describe Impact Flavors: 4-Mercapto-4-methylpentanone (4MMP)
Varietal Thiols
## Footnote
Cassis, guava, box tree
183
What are esters?
Fruity compounds produced by yeast during fermentation
184
Classify and Describe Impact Flavors: Isoamyl acetate
Esters
## Footnote
Banana, pear-drop, bubblegum
185
Classify and Describe Impact Flavors: Ethyl acetate
Esters
## Footnote
Fruity, nail polish remover
186
Classify and Describe Impact Flavors: Isobutyl acetate
Esters
## Footnote
Strawberry
187
Classify and Describe Impact Flavors: Ethyl Octanoate
Esters
## Footnote
Peach
188
What does 'foxy' refer to in a wine?
Distinctive varietal character associated with Vitis labrusca North American grapes
189
Name 4 examples of foxy grapes.
Concord
## Footnote
Catawba
## Footnote
Delaware
## Footnote
Niagara
190
Classify and Describe Impact Flavors: Methyl Anthranilate
Foxy
## Footnote
Artificial grape
191
Classify and Describe Impact Flavors: 2-Aminoacetophenone
Foxy
## Footnote
Corn tortilla, mothball, acacia
192
What factors does the harvest date determine?
Ripeness level
## Footnote
Chemistry
## Footnote
Flavors
## Footnote
Condition of the fruit
193
What factor determines a wine's potential alcohol?
Sugar concentration
194
How can heavy or prolonged rain impact grapes before harvest?
Dilute fruit
## Footnote
Induce rot
195
How can heat spikes impact grapes before harvest?
Susceptible to dehydration, leading to a dried fruit character in the wine
196
Name 2 styles of winemaking that require hand harvesting.
Whole cluster pressed
## Footnote
Carbonic maceration
197
What is the intent of sorting grapes after harvest?
To remove anything from the fruit that would confer unpleasant aromas or flavors
198
What is cluster sorting?
Removes materials other than grapes and compromised clusters
199
What is berry sorting?
Performed on destemmed fruit to remove raisins, small green 'shot' berries, pieces of stem and insects
200
How does destemming positively affect white wine making?
Allows more grapes to fit into the press
## Footnote
Reduces processing time
## Footnote
Increases extraction from the skins
201
In white winemaking, what happens prior to fermentation?
Juice is separated from stems and skins prior to fermentation
202
How does destemming positively affect white wine making?
Allows more grapes to fit into the press
Reduces processing time
Increases extraction from the skins
203
How does whole cluster pressing affect a wine in white winemaking?
Minimizes skin contact, resulting in clearer juice – fewer skin-derived compounds
204
How can stems be advantageous for pressing?
Act as a press aid, improving juice yields and clarification
205
What is the traditional and most common way red grapes can be processed?
Destemmed and crushed
206
Name 4 ways that red grapes can be processed after harvest.
Destemmed and crushed (Traditional; most common)
Destemmed but not crushed (whole-berry fermentation)
Not destemmed and crushed (fermentation with stems)
Not destemmed or crushed (whole-cluster fermentation, carbonic maceration)
207
What alcohol percentage needs to be acquired for carbonic maceration to start?
2% alcohol
208
Name an example of a wine made by semi carbonic maceration.
Beaujolais Nouveau
209
What is the main difference between carbonic maceration and semi carbonic maceration?
Carbonic maceration has carbon dioxide added
210
What is semi-carbonic maceration?
The practice of including a percentage of whole clusters to a fermentation
Juice in the bottom begins to ferment traditionally and produces carbon dioxide that induces carbonic maceration
211
What can be gained by including stems in a fermentation?
Increased concentration of phenolic compounds and potassium
212
Name 4 characteristics of a finished wine that used stem inclusion.
Lighter color
More tannic
Higher pH
Lower alcohol
213
What can be added during extraction to speed up the process?
Pectolytic enzymes
214
What are pectolytic enzymes?
Enzymes that break down grape skins
215
Name 2 reasons why skin extraction could be used for white wine making?
Increase the concentration of varietal aromas
Phenolic extraction – more texture
216
What is a disadvantage to using skin extraction for white wine making?
Can lend unpleasant bitter or green leafy flavors
217
What is the direct press method for rosé winemaking?
Whole red grape clusters are pressed and the juice is handled like white wine
218
What is the saignée method for rosé wine making?
Macerating the juice on the skins for a short time before bleeding juice off the tank
219
What is the typical period of skin contact for red wines?
10 to 21 days
220
What is cold soak?
Red grape must is held at low temperatures (close to 0˚ C) prior to fermentation, typically for 2 to 10 days
Believed to enhance color extraction
221
What is thermovinification and flash détente?
Niche vinification techniques that accelerate the extraction of red grapes by exposing them to very high heat for a short period of time
222
Describe the process of thermovinification.
Must is heated to between 140˚ - 180˚ F for a period of 30 minutes to 24 hours (higher temps require less time)
Must is pressed directly after heating
Fermentation proceeds off the skins
223
Describe the process of flash détente.
Must is heated rapidly to near-boiling temperatures (185˚ F), then cooled rapidly using a vacuum
Settled overnight, drained and pressed and fermentation proceeds off the skins
224
What is pressing?
Separates the juice (or wine, in the case of reds) from the skins and seeds and marks the end of the process of extraction
225
What flavor profiles result from a light press?
Aromatic and acidic
226
What is the result of heavy pressing grapes?
Darker color
More oxidized
Lower acid
More pectin and phenolics
Vegetal flavors
227
What is free run juice?
Juice liberated without the application of pressure
228
What is a batch press?
The press is loaded, grapes are pressed and the pomace is emptied out of the press
229
What is continuous pressing?
Grapes are loaded into the press and the pomace is expelled continuously
230
What is a basket press?
Traditional style of vertical press
Grapes are placed inside a cylindrical basket with a lid; pressure is applied to the lid and the grapes are compressed slowly, releasing their juice
231
What are pneumatic presses?
Most common type of press
A horizontal cylindrical tank with perforated screens or internal drains that allow juice to escape
232
What is a bladder press?
An inflatable cylindrical bladder in the center of the press that expands radially, compressing the grapes symmetrically against the tank’s sides
233
What is a membrane press?
Similar to a bladder press
The inflatable bladder is located along one side of the tank and grapes are compressed against the other side
234
What is a tank press?
A fully enclosed membrane press
Allows the absence of oxygen for very reductive winemaking
235
Name 3 ways oxidation can be minimized during pressing.
Dry ice
Juice
Sulfur dioxide
236
What is débourbage?
A form of clarification by settling overnight at cold temperature, followed by racking or decanting the juice off the solids that have settled to the bottom of the tank
237
What is flotation?
A form of clarification in which gas is pulsed through the juice so that the solids float to the top of the liquid
Solids can be skimmed or the tank drained
238
What role does bentonite play in the clarification process?
Acts as a settling aid, helping to remove grape solids, yeast, bacteria, pectin and proteins
239
What is chaptalization?
The addition of grape concentrate to increase the final percentage of ABV.
Used when grapes did not achieve sufficient sugar ripeness
240
What is the most common practice for reducing potential alcohol?
Adding water to the must
Typically done prior to fermentation
241
What acid is typically used to adjust acidity in wine?
Tartaric acid
242
How can tannin improve a wine when added to grape must?
Improve deficiencies
Stabilize color
Improve a wines tannin structure
243
What are tannins that are added to wine called?
Enological or exogenous tannins
244
What is the name of the yeast responsible for alcoholic fermentation?
Saccharomyces cerevisiae
245
What is the name of the yeast responsible for malolactic fermentation?
Oenococcus oeni
246
What is Brettanomyces?
A spoilage yeast that is responsible for a number of off-aromas and flavors in wine as well as some pleasant ones
247
Name 4 flavors Brettanomyces impart in a wine.
Barnyard
Bandaid
Leather
Horse
248
What 2 categories of bacteria are relevant in wine?
Lactic acid bacteria
Acetic acid bacteria
249
What is pied de cuvee?
A portion of yeast rich already fermenting grape must may be used to inoculate fermentation
250
What is a stuck fermentation?
Yeasts stop converting the sugar into alcohol and carbon dioxide, leaving undesired residual sugar in the wine
251
What is fermentation?
The anaerobic conversion of carbohydrates into energy by enzymes
252
What is glycolysis?
Yeast converts sugar into energy
253
Name the 3 stages for yeast fermentation.
Lag phase
Exponential phase
Stationary phase
254
What is the lag phase?
Yeast adapts to the high sugar environment; little population growth
255
What is the exponential phase?
Yeast reproduces building up a critical population; yeast will begin fermenting
256
What are mercaptans?
The result of hydrogen sulfide combining with wine components like yeast and producing a pungently offensive sour odor that can smell like garlic, stale sweat, skunk or rubber
257
How can hydrogen sulfide be blown off during the fermentation process?
Aerative cap management, Copper fining
258
What is reductive winemaking?
An environment lacking oxygen; preserves fresh and fruity aromatics; avoids oxidation and flavor markers
259
Name 4 reductive winemaking practices.
Use of stainless steel
Aging on the lees
Fewer transfers
Using inert gas or dry ice
260
What flavor profiles define 'positive reduction'?
Matchstick, Flint
261
What kind of reaction is fermentation?
Exothermic – producing heat
262
What factors can impact the fermentation temperature?
Yeast strain
Presence of whole clusters
Size and material of the fermentation vessel
263
What temperature range does yeast require to be active? When are they most active?
45˚ - 95˚ F
Mid 70s – mid 80s F
264
What temperature range do white wine fermentations occur?
Mid 40s – mid 60s F
265
What is the resulting style of a white wine fermented at a cooler temperature?
Crisp styles
266
What is the resulting style of a white wine fermented at a warmer temperature?
Riper, richer fruit; Floral driven aromas
267
What temperature range do red wine fermentations occur? Why?
Mid 70s – low 90s F
To facilitate extraction from the skins and extraction of flavor
268
During red wine fermentations, what do higher temperatures extract?
More tannin and phenolic compounds – darker, fuller bodied wines
269
During red wine fermentations, what do lower temperatures extract?
More fruit and bright wines; Fresh flavors
270
Name 3 means of cap management including their French terms.
Pumpover (remontage)
Punchdown (pigéage)
Rack and return (délestage)
271
Describe the pumpover process.
Juice is pumped from the bottom of the tank over the top; The liquid may be returned to the tank using an irrigator or sprinkler – provides gentle but thorough wetting of the cap; Fire hosing – more extractive
272
Describe the punchdown process.
Use a plunger or a large foot to mix the tank by pushing the cap into the liquid portion; Does a better job of breaking berries apart
273
Describe the process of rack and return.
The entire liquid portion of the must is drained into another tank, leaving the skins behind; Liquid portion is pumped back over the top of the original tank
274
How does rack and return affect the wine/fermentation process?
Breaks up the cap; Lowers the fermentation temperature; Provides the most complete mixing possible; Extraction is more efficient
275
What is submerged cap fermentation?
Cap is intentionally submerged throughout the fermentation; Ensures the skins stay in contact with the liquid – greater extraction
276
Where is submerged cap fermentation common?
Piemonte
277
Name 2 grapes that punchdowns are commonly used for.
Pinot Noir, Syrah
278
What varieties typically use pumpovers?
Bordeaux varieties
279
What is extended maceration?
Leaving the wine on the skins for several weeks to months after primary fermentation is completed
280
What are the advantages to extended maceration?
More seed tannin; Increases the rate of phenolic polymerization – more sweetness on the midpalate
281
How can a fermentation be stopped?
Temperature reduction and sulfur addition; Filtration or centrifugation; Fortification with a high proof spirit
282
What is bâtonnage?
Lees stirring; Resuspends lees that have settled to the bottom of a barrel
283
How does bâtonnage affect a wine?
Encourages the fermentation to finish; Improve mouthfeel; Keeps lees fresh; Reduces reductive aromas
284
When do stuck fermentations occur?
When the yeast becomes unduly stressed due to fermentation conditions, competition or a sudden change in temperature
285
Name a corrective measure that can be employed before a stuck fermentation occurs.
Warming and frequent mixing (or stirring) of the tank – keeps yeast in suspension – more access to sugar
286
What are gross lees?
A combination of live and dead yeast that settles out of the wine
287
How can malolactic fermentation be blocked?
Through the addition of sulfur dioxide
288
What is malolactic fermentation?
Malic acid is converted to lactic acid by lactic acid bacteria
289
How does malolactic fermentation affect a wine?
Lowers a wine’s acidity; Stabilizes the wine
290
What characteristic do lactic acid bacteria impart on a wine?
Wine aroma and flavor compounds: Acetic acid, Acetaldehyde, Diacetyl (most recognizable product of malolactic fermentation)
291
Why would winemakers want to wait until primary fermentation is complete before malolactic fermentation initiates?
Avoids competition between yeast and bacteria – could lead to stuck fermentation Reduces the risk of high volatile acidity
292
What are some advantages to delaying malolactic fermentation?
Allows wine to be unsulfured for longer – less total sulfur use
Creates stable pigments – intensifying color
293
At what temperature range should wines generally be stored at after primary and malolactic fermentation?
45˚ - 65˚ F
294
How does oxidation affect a wine?
Reduce astringency, varietal and fruity aromas
Create flavors expected in aged wine
295
How can wines be protected post primary fermentation?
SO2 addition
Topping
Inert gasses
Aging on the lees
296
What styles can slow oxygen exposure benefit?
Tannic red wines
297
What does aging a wine in oak impart in a wine?
Flavor
Aroma compounds
Tannin
298
How do smaller sized oak aging vessels impact a wine? Why?
More impacted by oak flavors
More oxygen exposure
Surface area to volume ratio is larger
299
How do larger sized oak aging vessels impact a wine? Why?
Less impacted by oak flavors
Less oxygen exposure
Surface area to volume ratio is smaller
300
What aging vessel is common for wines that emphasize fruit and freshness?
Stainless steel
301
What is micro-oxygenation?
Red wine making technique that introduces a slow dose of oxygen to a wine over time
302
Where was micro-oxygenation invented?
Madiran, France
303
What are the benefits to using micro-oxygenation?
Soften tannin
Stabilize color
Reduce herbaceous, vegetal or reductive aromas
304
What are some disadvantages to micro-oxygenation?
Premature oxidation
Loss of fruit flavors
305
What is cliquage?
Similar to micro-oxygenation; Larger dose of oxygen is added to the wine to mimic the oxygen pick up that would be expected during racking
306
What are the benefits to oak aging?
The addition of flavor and tannin
Concentration through evaporation
Slow oxidation – softer, more mature profile
307
Why is white oak ideal for winemaking?
Lightweight
Watertight
Malleable hardwood
308
What 2 oak species make up French oak barrels?
Quercus robur
Quercus petraea (Quercus sessilis)
309
What oak species makes up American oak barrels?
Quercus alba
310
Characterize Quercus robur.
Coarser grained
More tannic
311
Characterize Quercus petraea.
Medium tannin
Medium lactones
Elevated levels of triterpenoids – contribute sweetness
312
Characterize Quercus alba.
Dense
Less tannin
Higher concentration of oak lactones – more vanilla and coconut flavors
313
What 2 species of oak make up Hungarian oak?
Quercus robur, Quercus petraea
314
Name 7 forests in France that grow oak for barrels.
Tronçais
Allier
Jupilles
Nevers
Bertranges
Vosges
Limousin
315
Which forests produce tighter grained oak?
Tronçais
Allier
Jupilles
316
Which forests produce medium grained oak?
Nevers
Bertranges
317
Which forest produces looser grained oak?
Vosges
318
Which forest produces coarse grained oak often used for spirits?
Limousin
319
What forest is Hungarian oak harvested from? Characterize it.
Zemplén Hills
Tight grained
320
How is barrel toast described?
Light
Medium
Medium plus
Heavy
321
What aromas do heavily toasted barrels impart?
Less oak lactone and tannin
Grilled, smoky and toasty aromas
322
When is oak the most impactful? How can this impact a wine?
New oak
Imparts flavors and tannin
323
At what point is an oak barrel considered neutral?
By the third to fifth fill
324
Why would producers use both new and neutral oak?
Oak lactones are indefinitely released from the wood in an acidic environment; winemakers can adjust based on optimal flavor contributions
325
How many liters do Bordeaux barrels hold?
225 L
326
How many liters do Burgundy barrels hold?
228 L
327
What are the names for oak tannins?
Hydrolysable tannins or ellagitannins
328
What flavor compounds do cis and trans- oak lactones impart in a wine?
Oaky
Vanilla
Coconut
Sweet
Cocoa
329
How can vanillin be reduced in winemaking?
Barrel fermentation – vanillin is converted to vanillic acid by yeast
330
How can Brettanomyces be bred in a winery?
Used barrels that are not cleaned properly
331
How are barrels discouraged from microbial growth?
Empty barrels are often treated with SO2 gas
332
Name 4 oak alternatives used in winemaking.
Chips
Oak dust
Oak powder
Staves
333
What is the French term for topping?
Ouillage
334
What is topping?
Generally performed every 2 to 6 weeks Replaces the volume of wine lost to the atmosphere
335
Where does most of the oxygen exposure come from during aging?
The bunghole
336
What flavor is typically associated with oxidation?
Acetaldehyde
337
Name 2 advantages to using sulfur dioxide in winemaking.
Reduce the impact of oxidation
Limit microbial growth
338
What is the French term for racking?
Soutirage
339
What is racking?
A cellar operation that clarifies and aerates wine
340
Describe the process of racking.
Wine is pumped or siphoned through a racking wand or racking arm, which is placed just above the layer of solids; Wine is drawn off leaving the solids behind
341
When may racking occur?
In white winemaking, just after pressing and prior to fermentation; After primary fermentation; After malolactic fermentation; Periodically throughout aging; During blending; After fining; After cold stabilization
342
Why would a winemaker choose to rack after pressing but before fermentation in white winemaking?
To remove solids
343
Why would a winemaker choose to rack after primary fermentation?
To remove the gross lees or the large volume of lees generated during fermentation
344
Why would a winemaker choose to rack after malolactic fermentation?
To remove lees prior to the addition of SO2
345
Why would a winemaker choose to rack periodically during aging?
To clarify and aerate the wine
346
Why would a winemaker choose to rack after fining?
To remove fining agents and/or prior to filtration
347
Why would a winemaker choose to rack after cold stabilization?
To remove tartrate crystals
348
What is soutirage à l’esquives?
Draining the wine through a valve on the face of the barrel, a winch then inverts the barrel decanting the wine off the lees until sediment appears
## Footnote
Traditional method of racking still employed in France
349
What is the French term for blending?
Assemblage
350
What is blending?
The determination of the proportion of each lot to be used in a finished wine.
## Footnote
Physically combining the wines.
351
What process can be used as an alternative to racking?
Centrifugation
352
What is fining?
Selectively removes undesirable components in order to make a wine more pleasurable or stable
353
How can tannin fining with protein affect a wine?
Can smooth out aggressive tannins in red wines
## Footnote
Can reduce bitterness caused by small phenolic compounds or pigments from skin contact or oxidation in white wine.
354
Name 4 naturally occurring proteins used to fine wine.
Casein (milk)
Albumin (egg white)
Isinglass (fish swim bladder)
Gelatin (tendons and muscles)
355
Name 2 vegan fining agents.
PVPP
Nylon
356
Why would bentonite fining be used?
Used to ensure that the wine is heat stable
## Footnote
Remove proteins from finished white wine.
357
When is bentonite used in white winemaking? Why?
At the juice stage, just after pressing
To remove grape solids and clarify the juice prior to fermentation
## Footnote
To remove grape solids and clarify the juice prior to fermentation.
358
Why would copper fining be used?
Removes unpleasant thiols or mercaptans, that cause reductive aromas (rotten eggs, onion, garlic, skunk) in wine
359
How can excess copper levels impact a wine?
Increase the rate of oxidation
## Footnote
Reduce varietal thiols. Can cause haze or red brown precipitate in bottled white wines (at high levels).
360
What is copper casse?
A haze or red brown precipitate found in bottled white wines with high levels of copper
361
How does filtration clarify wines or prevent microbial spoilage?
Physically removes yeast and bacteria
362
What is depth filtration?
Wine is passed through a relatively thick filter media often made of diatomaceous earth (DE or Kieselguhr) and/or cellulose (paper)
## Footnote
Forms a sort of maze and as the wine passes through, larger particles are trapped.
363
What is pad filtration?
Wine is filtered through performed paper pads that may contain DE
## Footnote
Can leave a paper taste in the wine if pads are not properly rinsed.
364
What is lenticular filtration?
The wine is passed through a performed paper and DE cylindrical cartridge
365
What is plate and frame filtration?
A support screen is coated with DE and wine that has been mixed with DE is passed through the screen; filter media is constantly replenished
366
What is rotary drum filtration?
Similar to plate and frame filtration but the support screen is cylindrical
## Footnote
Can be very oxidative.
367
What is surface filtration?
Wine is passed through a perforated plastic membrane with a uniform pore size
## Footnote
Considered absolute- filtering all of the particles larger than the filter rating.
368
What is stabilization?
The process of ensuring that a wine won’t change unpredictably once in bottle.
369
Why can physical instability in a wine occur?
Changes in temperature
## Footnote
Changes in pH. Alcohol content.
370
What is microbial instability?
Reactivation of yeast or bacteria once the wine is in bottle
371
What does cold stabilization do?
Reduces the likelihood of crystals forming in the bottle
372
Name 2 methods to cold stabilize wine.
Refrigeration – holding the wine at a very low temperature for several weeks followed by racking
Addition of potassium bitartrate crystals – hastens the crystallization process
373
What is Lysozyme? What is it used for?
An enzyme derived from egg whites
Prevent malolactic fermentation or to destroy lactic acid bacteria.
374
What is Chitosan? What is it used for?
Positively charged fining agent derived from the exoskeleton of crustaceans
Removes yeast, including Brettanomyces.
375
What is sorbic acid used for?
Inhibits the growth of yeast, but lactic acid bacteria can convert it to a floral scented compound responsible for geranium taint.
376
What is Dimethyl decarbonate (DMDC) known as? What is it used for?
Velcorin
Kills yeast and bacteria very effectively. Can be added on the bottling line as an alternative to filtration or higher levels of SO2.
377
What is pasteurization?
Heating the wine to a high temperature.
## Footnote
Occurs at bottling.
378
Name 4 of the major closures used in wine production.
Traditional cork
Technical cork (DIAM)
Synthetic cork (Normacorc)
Screwcaps
379
What is a negative flavor that a traditional cork can impart on a wine?
Trichloranisole (TCA)
380
What is oxygen transmission rate?
Determines how a wine will age in bottle
381
Name 4 forms of packaging for wine that is not glass.
Can
Bag in box
Tetra paks
Plastic bottles
382
What does the term “shiner” refer to during bottling? Where is it common practice?
Freshly bottled wine stored and labeled just prior to fulfillment
Europe
383
What are the benefits of fining?
Remove excessive tannin
Improve balance
Clarify minute solids – unstable proteins
## Footnote
Improve balance. Clarify minute solids – unstable proteins.
384
What French region widely uses egg whites as a fining agent?
Bordeaux
385
What fining agent could be used to help remove smoke taint?
Activated carbon (derived from charcoal)
386
What is the benefit of filtering?
Helps stabilize a wine microbially
Helps clarify it by removing suspended particles
387
How can diacetyl be removed in a wine?
The wine can be left in the barrel for several days after malolactic fermentation
## Footnote
Yeasts remaining in the juice will metabolize the diacetyl.
388
What is sur lie?
“On the lees”.
## Footnote
The wine rests in contact with a thick layer of lees that have settled at the bottom of the barrel.
389
What effect does sur lie have on a wine?
Adds a slightly richer texture and sometimes more complexity to a wine.
390
List 4 ways that pomace can be used post pressing.
Pomace brandies – marc
Grappa
Plowed back into the field
Composted
391
What is must?
A combination of juice and berries.
392
What is the purpose Rectified Grape Must Concentrate/ RGCM?
To enrich juice prior to fermentation in the event of insufficient sugar
393
Name 3 advantages to using stainless steel tanks for fermentation.
Airtight
Easy to clean
Provide temperature control
394
At what alcohol percentage can yeast survive in?
Up to 14%
395
What is a centrifuge?
A modern piece of laboratory equipment that uses accelerated gravity to separate the wine from heavier solids
396
Describe the process of rotofermentation.
Agitating the fermenting must in a specialized fermentation vessel that either rotates on its own or contains an inner paddle that mixes the fermenting must
397
What is Vin Gris?
“Grey wine” in French
A rosé made from red grapes but with a very pale, almost white color
398
Why are Chenin Blanc and Sémillon prone to botrytis?
Thin skinned
399
Name 3 European wines that make Traditional Method Sparkling.
Cava – Spain
Franciacorta – Italy
Crémant – certain appellations in France
400
Why are grapes for traditional sparkling wine harvested early?
Maintain low sugar/high acid character
401
What is the tank method referred to in Italy?
Martinotti Method
402
What is passerillage?
The process of drying and concentrating grapes either on teh vine or after harvest
## Footnote
Producess sweet, rich wines
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