Wset Level 4 Viticulture & Vinification Exam Questions Fully Solved Latest Update 2025 Already
Passed
Photosynthesis - Answers Synthesis of sugar from CO2 and H2O under the influence of sunlight and with
the aid of chlorophyll
Sugars produced by photosynthesis - Answers Sucrose which hydrolyses into glucose and fructose once
it reaches the grapes
Study of the Vine - Answers Ampelography
Vine Family - Answers Vitaceae
Vine Genus - Answers Vitis
Vine Species used most - Answers Vitis vinifera
Clone - Answers Selection of a vine that has characteristics that set it apart from the majority
Photosynthesis Chemical Equation - Answers 12CO2 + 11H2O = C12H22O11 + 12O2
Hydrolysed Sucrose Equation - Answers C12H22O11 (Sucrose) + H2O = C6H12O6 (Glucose) + C6H12O6
(Fructose)
2 Main Acids in Grapes - Answers Malic Acid HOOC.CHOH.CH2.COOH Tartaric Acid
HOOC.CHOH.CHOH.COOH
Together 90% of total acids
Gluconeogenesis - Answers Conversion of malic acid into glucose
Formation of Tartaric Acid - Answers As a by product of sugar synthesis
Acid level change with grape maturity - Answers Malic acid decreases (due to grape use for energy and
gluconeogenesis) while Tartaric increases in proportion to sugars, but total Acid goes down as
proportionately sugars go up
Most abundant Mineral Salts in Grapes - Answers Potassium (K) most abundant
Potassium in Grapes - Answers Rises as sugars increase, associated with tartrate crystals (potassium
bitartrate)
Other minerals in grapes (4) - Answers Calcium (Ca) tartrate formation
Magnesium (Mg), Iron (Fe), Copper (Cu)
Flavonoids (Polyphenols) in Grapes - Answers Found in skin and stems
Powerful antioxidants
,Tannins & Anthocyanins
Tannins in Grapes - Answers Found in Skin, Stems, Pips
Tough outer cells of skins
Anthocyanins - Answers Responsible for color
Softer inner cells of skins
Heat and alcohol accelerate coloring
Flavor components in grapes - Answers Esters, Higher Alcohols, Aldehydes, Terpenols, Hydrocarbides
Proteins and Colloids in Grapes - Answers Proteins & Amino Acids give Nitrogen for yeast, but cause
haziness
Colloids are large complex components and can be stable or unstable in the wine
Veraison - Answers Happens in June / July
Grapes change color - Green to Red or White / Translucent
Sugars start to accumulate more rapidly pushing down acid levels
Acetic Bacteria - Answers Promote conversion of ethanol into acetic acid by oxidation
CH3CH2OH (ethanol) + O2 = CH3COOH + H2O
Anaerobic Winemaking - Answers Without oxygen as much as possible
Antioxidant in the vineyard - Answers Potassium Metabisulphite Powder, liberates Sulphur Dioxide (SO2)
when wet
Inert Gasses - Answers CO2, Nitrogen, Argon to flush out all tanks and hoses of O2
Enzymes encouraging oxidation - Answers Oxidizing Enzymes (Oxidases), Metal Ions, Copper being worst
CO2 as inert gas (Pros / Cons) - Answers Pros: Cheap, easy, heavier than air
Cons: Can dissolve in wine (espec when cold), can kill (at a proportion of 5%)
Nitrogen as inert gas (Pros / Cons) - Answers Pros: Insoluble in wine, won't kill you
Cons: Same density as air (requires 2x as CO2), can cause foam on wine
Argon as inert gas (Pros / Cons) - Answers Pros: won't dissolve or cause foam, denser than Nitrogen (like
CO2), won't kill you
Cons: Expensive, hard to find food-grade
,O2 to SO2 Ratio - Answers Every molecule of O2 dissolves 4x its weight in SO2 as can be seen by relative
molecular weights
2SO2 (128) = O2 (32)
Sparging - Answers Injecting fine bubbles into a liquid to remove dissolved oxygen.
Can remove flavor compounds or CO2 (flat wine) if done poorly
Gasses used in Sparging - Answers Nitrogen (but removes CO2)
Mix of N and CO2 to control
When is O2 good for wine making? (6) - Answers 1. Hyperoxidization - giving the must a short burst
during clarification to rid of fragile components and stabilize
2. Before fermentation to kick start the yeast
3. If fermentation is slow
4. Before bottling to prevent reductive taint
5. Oxidizing harsh polyphenols in red wine during barrel maturation
6. Add character and complexity
Crushing Grapes - Answers Misnomer. Ripping the grape apart to let the free run juice flow
Must be careful to not tear pulp away from skins or to tear apart stems both of which release harsh
flavor and tannin
Free Run Juice Yield - White Wine - Answers 400 - 500 Liters per ton of grapes
Press Juice Yield - White Wine - Answers 150 - 200 Liters per ton of grapes
Effect of pressure in pressing - Answers Higher the pressure more tough cells erupt and harsher tannins
and bitter flavors released
Basket Press - Answers Used for thousands of years
AKA Vertical screw press
Increase pressure by screwing down lid
Cons: Cannot be hurried, Oxygen enters, labor intensive
Pros: Good clarity
, Used in Champagne
Vertical Screw Press - Answers Horizontal basket press with two pistons
Pros: Can be automated reducing labor and time
Cons: Coarse juice due to skin abrasion from tumbling and high pressure
Pneumatic Press - Answers Cylindrical bladder inflates with air or cold water and presses the grapes
against a perforated wall
Pros: Low pressue
Tank Press - Answers Pneumatic Press inside a sealed tank without oxygen
Continuous Screw Press - Answers For large wineries
Can squeeze grapes bone dry - only for brandy
SO2 on White Wine Must - Answers Critical as clarification will take a few days and wine might oxidize or
ferment. Kills bacteria, stuns weaker yeast
SO2 on Red Wine Must - Answers Difficult - microorganisms on skins impervious, some produce
acetaldehyde which binds to the SO2 and removes the free SO2
Can improve extraction of polyphenols from the skins
Wine without SO2? - Answers Possible, but very hard. Must be careful of oxidation.
Even organic wines use SO2
Clarification of White / Pink - Answers Pre-Fermentation
Be careful not to remove too many solids as the proteins and amino acids are adsorbed and nutritional
to yeast
Clarification, Centrifuge, Flotation
Settling in White Wines - Answers A method of clarification
12-24 hours to let particles settle
Long period, SO2 critical and must chilled below 15C to prevent oxidation and fermentation
Centrifuging - Answers A method of clarification
High speed spinning machine
Shortens time to 2 hours
Passed
Photosynthesis - Answers Synthesis of sugar from CO2 and H2O under the influence of sunlight and with
the aid of chlorophyll
Sugars produced by photosynthesis - Answers Sucrose which hydrolyses into glucose and fructose once
it reaches the grapes
Study of the Vine - Answers Ampelography
Vine Family - Answers Vitaceae
Vine Genus - Answers Vitis
Vine Species used most - Answers Vitis vinifera
Clone - Answers Selection of a vine that has characteristics that set it apart from the majority
Photosynthesis Chemical Equation - Answers 12CO2 + 11H2O = C12H22O11 + 12O2
Hydrolysed Sucrose Equation - Answers C12H22O11 (Sucrose) + H2O = C6H12O6 (Glucose) + C6H12O6
(Fructose)
2 Main Acids in Grapes - Answers Malic Acid HOOC.CHOH.CH2.COOH Tartaric Acid
HOOC.CHOH.CHOH.COOH
Together 90% of total acids
Gluconeogenesis - Answers Conversion of malic acid into glucose
Formation of Tartaric Acid - Answers As a by product of sugar synthesis
Acid level change with grape maturity - Answers Malic acid decreases (due to grape use for energy and
gluconeogenesis) while Tartaric increases in proportion to sugars, but total Acid goes down as
proportionately sugars go up
Most abundant Mineral Salts in Grapes - Answers Potassium (K) most abundant
Potassium in Grapes - Answers Rises as sugars increase, associated with tartrate crystals (potassium
bitartrate)
Other minerals in grapes (4) - Answers Calcium (Ca) tartrate formation
Magnesium (Mg), Iron (Fe), Copper (Cu)
Flavonoids (Polyphenols) in Grapes - Answers Found in skin and stems
Powerful antioxidants
,Tannins & Anthocyanins
Tannins in Grapes - Answers Found in Skin, Stems, Pips
Tough outer cells of skins
Anthocyanins - Answers Responsible for color
Softer inner cells of skins
Heat and alcohol accelerate coloring
Flavor components in grapes - Answers Esters, Higher Alcohols, Aldehydes, Terpenols, Hydrocarbides
Proteins and Colloids in Grapes - Answers Proteins & Amino Acids give Nitrogen for yeast, but cause
haziness
Colloids are large complex components and can be stable or unstable in the wine
Veraison - Answers Happens in June / July
Grapes change color - Green to Red or White / Translucent
Sugars start to accumulate more rapidly pushing down acid levels
Acetic Bacteria - Answers Promote conversion of ethanol into acetic acid by oxidation
CH3CH2OH (ethanol) + O2 = CH3COOH + H2O
Anaerobic Winemaking - Answers Without oxygen as much as possible
Antioxidant in the vineyard - Answers Potassium Metabisulphite Powder, liberates Sulphur Dioxide (SO2)
when wet
Inert Gasses - Answers CO2, Nitrogen, Argon to flush out all tanks and hoses of O2
Enzymes encouraging oxidation - Answers Oxidizing Enzymes (Oxidases), Metal Ions, Copper being worst
CO2 as inert gas (Pros / Cons) - Answers Pros: Cheap, easy, heavier than air
Cons: Can dissolve in wine (espec when cold), can kill (at a proportion of 5%)
Nitrogen as inert gas (Pros / Cons) - Answers Pros: Insoluble in wine, won't kill you
Cons: Same density as air (requires 2x as CO2), can cause foam on wine
Argon as inert gas (Pros / Cons) - Answers Pros: won't dissolve or cause foam, denser than Nitrogen (like
CO2), won't kill you
Cons: Expensive, hard to find food-grade
,O2 to SO2 Ratio - Answers Every molecule of O2 dissolves 4x its weight in SO2 as can be seen by relative
molecular weights
2SO2 (128) = O2 (32)
Sparging - Answers Injecting fine bubbles into a liquid to remove dissolved oxygen.
Can remove flavor compounds or CO2 (flat wine) if done poorly
Gasses used in Sparging - Answers Nitrogen (but removes CO2)
Mix of N and CO2 to control
When is O2 good for wine making? (6) - Answers 1. Hyperoxidization - giving the must a short burst
during clarification to rid of fragile components and stabilize
2. Before fermentation to kick start the yeast
3. If fermentation is slow
4. Before bottling to prevent reductive taint
5. Oxidizing harsh polyphenols in red wine during barrel maturation
6. Add character and complexity
Crushing Grapes - Answers Misnomer. Ripping the grape apart to let the free run juice flow
Must be careful to not tear pulp away from skins or to tear apart stems both of which release harsh
flavor and tannin
Free Run Juice Yield - White Wine - Answers 400 - 500 Liters per ton of grapes
Press Juice Yield - White Wine - Answers 150 - 200 Liters per ton of grapes
Effect of pressure in pressing - Answers Higher the pressure more tough cells erupt and harsher tannins
and bitter flavors released
Basket Press - Answers Used for thousands of years
AKA Vertical screw press
Increase pressure by screwing down lid
Cons: Cannot be hurried, Oxygen enters, labor intensive
Pros: Good clarity
, Used in Champagne
Vertical Screw Press - Answers Horizontal basket press with two pistons
Pros: Can be automated reducing labor and time
Cons: Coarse juice due to skin abrasion from tumbling and high pressure
Pneumatic Press - Answers Cylindrical bladder inflates with air or cold water and presses the grapes
against a perforated wall
Pros: Low pressue
Tank Press - Answers Pneumatic Press inside a sealed tank without oxygen
Continuous Screw Press - Answers For large wineries
Can squeeze grapes bone dry - only for brandy
SO2 on White Wine Must - Answers Critical as clarification will take a few days and wine might oxidize or
ferment. Kills bacteria, stuns weaker yeast
SO2 on Red Wine Must - Answers Difficult - microorganisms on skins impervious, some produce
acetaldehyde which binds to the SO2 and removes the free SO2
Can improve extraction of polyphenols from the skins
Wine without SO2? - Answers Possible, but very hard. Must be careful of oxidation.
Even organic wines use SO2
Clarification of White / Pink - Answers Pre-Fermentation
Be careful not to remove too many solids as the proteins and amino acids are adsorbed and nutritional
to yeast
Clarification, Centrifuge, Flotation
Settling in White Wines - Answers A method of clarification
12-24 hours to let particles settle
Long period, SO2 critical and must chilled below 15C to prevent oxidation and fermentation
Centrifuging - Answers A method of clarification
High speed spinning machine
Shortens time to 2 hours
