Winemaking
Name 3 ways of producing a rosé wine
- Vin d'une nuit (overnight skin contact) or short maceration
- Saignée (drain wine off a red wine fermentation to concentrate the red and get a rosé biproduct)
- Direct press
What are the benefits of using pectinolytic enzymes in winemaking?
- Improves juice extraction
- Facilitates filtration
- Improves stability of taste, texture, color, and aromas
Name the smell of the fault
- Caused by acetaldehyde due to oxidation
- Can be avoided with protective winemaking, SO2, and cool fermentation
Bruised apple
Name the agent:
- Reduces color and odor
- Fungal remover
- Helps with reductive aromas
- Reduces concentration and binds to everything
Activated Charcoal
Name the agent:
- Removes unwanted hydrogen sulphides and sulfur aromas (rotten egg)
- Toxic in higher doses, environmental concerns
- Instabiliy
Copper Sulfate
What is the difference between an autovinifier and délestage
Autovinifer - anaerobic, no power needed, keeps the wine circulating over the cap with pressure and gravity
Délestage - Rack and return (drain wine into another tank and then spray over the cap in the first tank)
Where does betaglucanase come from and how does it affect the wine?
- Produced from noble rot or by the yeast during autolysis
- Thickens the wine and makes it hard to filter, clogging the mesh and hindering clarification
Name the fault scent:
- Caused by H2S from nutrient deficient must
- Solutions include aeration, copper sulfate, racking or a yeast strain low H2S
Rotten egg
Name the agent
- Reduces yellowing and browning
- Reduces bitterness
- Used in whites and rosés
- diminishes color and can clog filters
Casein
Name the agent:
- Clarifies (white) wines
- Removes protein haze
- Helps with protein instability
- Absorbs anthocyanins
Bentonite
What is the function of SO2 in winemaking?
Prevents oxidation or fixes signs of oxidation (antioxidant), kills some bacteria and fungus forming organisms (antiseptic), kills particles can could cause oxidation (antioxidasic)
Where does laccase come from and what does it do to wine?
- Noble rot or rot in general
- Cause oxidation in wine (browning and odors) even after fermentation
Name the fault scent:
- caused by acetic or ethyl acetate (from an acetobactor)
- SO2 to block bacteria, prevent oxidation, irreversible
Vinegar or nail polish remover
(Also accept volatile acidity)
Name the agent
- Removes phenol compounds
- Removes bitterness and astringency
Overfining will cause cloudiness (protein)
Gelatine
Main use of Calcium Phytate
Prevent haze in wines high in iron
(can impact titratable acidity and pH)
What is one way to avoid oxidation and reduction at the same time?
Micro-oxygenation
What is the use of glycosidase enzymes?
- Enhances aromas and aromatics
- Cure smoke taint by reducing the concentrations of phenolic glycosides by cleavage of their sugar units releasing volatile phenols at early stages of winemaking.
Name the fault scent:
- Caused by Dimethylsufide (DMS) from poor yeast management, overheating, long cold soaks, and reduction
- Solutions: Activated charcoal
Cauliflower
Name uses for Islinglass
- Unmasks fruit flavors in whites
- Strips color
- Removes harsh tastes, astringency (to a lesser degree), browning, colloidal haze, and oxidation
- Produces a heavy deposit, fish aromas, and haziness if overused
Name benefits of Chitosan
- Clarifying agent
- Reduces heavy metals
- Reduces scent of Brettanomyces
Name two methods of tartate stabilization
- Cold stabilization
- Contact process: bringing the wine into contact with microcrystals of potassium bitartrate, enabling the crystallization to occur more readily
- Ion exchange: Ion exchange resin
- Electrodialysis: selective membranes to allow the passage of potassium and calcium ions
- Mannoproteins: from the cell wall of yeast during autolysis
MORE
What is tyrosinase's effect on wine?
Oxidation
Name the fault:
- Caused by poor hygiene and lack of protective winemaking
- Smells like horse sweat
Brettanomyces
Name pros and cons of PVPP
- Stabilizes wine color
- Reduced astringency by removing tannins
- Only works on certain polyphenols and needs to be used in moderate doses
Benefits and risks in using silica sol
pros: binds with colloidal particles and proteins in white wines
cons: sometimes needs to be combined with another agent for perfect clarity, can leave a residue of silica in the wine