Vinification Flashcards
How can oxygen be avoided in the winery, 5 points
Avoiding ullage SO2 addition Inert gas purging or blanketing Impermeable containers Cool & constant temperatures
How can oxygen be increased in the winery, 5 points
Use of cap management use of small wooden barrels increasing the number of racking allowing ullage hyperoxidation/microoxidation
Max permitted SO2 levels for EU
Whites - 210mg/L
Red - 160mg/L
White wine fermentation temps? (Higher and Lower) Describe the types of wine style for each
Lower - 12 - 16 Fresh fruity light
Higher - 18 - 25 Less fruity, barrel fermented
Red wine fermentation temps ?(Higher and Lower) Describe the types of wine style for each
Lower 18-25 - Fruity low tannins
Higher 25-35 (MAX) Pronounced flavour, tannin and colour
Above 35 yeast will die.
Prefermentation maceration in reds is better for extraction of _____
Colour as anthocyanins are soluble in water
Post fermentation maceration in reds is better for extraction of _____
Tannins as tannins are soluble in alcohol
Name the 7 wine components
Water Sugar Alcohol Phenolics (Tannin & Anthocyanins) Aromatics Glycerol Acid
Where type of sorting can be done?
In the vineyard
Vibrating belt at reception with hand sorting
Optical sorting (100 grape sample)
3 ways of creating a sweet wine
Concentration sugars
Stopping fermentation
Adding sweet component
What is the component called that can drain after crushing?
Free run juice
Name 4 different types of Press
Pneumatic press
Basket press/Champagne press
Horizontal Press
Continuous Press
What are the advantages and disadvantages of a pneumatic press?
Gentle, can be fully atomised, can be used to chill by filling bladder with water, can be flushed with inert gas,
Is a batch process.
What are the advantages and disadvantages of a basket press?
It allows the ingress of oxygen (can be a negative)
Is gentle and arguably more gentle than pneumatic
Labour intensive
Smaller load size
Name 5 types of must adjustment and 1 way they are done
Acidification - Tartaric acid
Deacidification - Calcium Carbonate (Chalk)
Enrichment - RCGM, Chapilisation, cyroextration, reverse osmosis
Reducing potential alcohol - Watering down
Adding tannins.
Name two ways of chilling grapes at reception and positives/negatives
Storage in large chillers - Takes a long time, costly in energy
Heat exchangers - Fruit must be in more liquid form, fast, expensive to purchase.
Describe fermentation using a small flow chart
SUGAR + YEAST (ANEROBICALLY) —-> ALCOHOL (ETHANOL) + C02
Name two types of phenolic
Tannins & Antocyanins
SO2 is a what? 2 points
Anti-oxidant
Anti-Microbial
Describe how oxidation can be reduced during harvest and transport.
Harvesting at night
Addition of SO2
Chilling grapes upon arrival to winery
Using small baskets to minimise crushing
Fermentation also produces what other products along with ethanol and C02?
Volatile acidity
Wine aromatics from precursors and yeats (thiols 4MMP - gooseberry sauv B) (esters - fruity aromas)
Glycerol
Advantages and disadvantages of ambient yeast
Free, adds complexity, can be part of marketing
Fermentation can start slowly and lead to spoilage, Can take longer to ferment to dryness, consistent product cannot be guaranteed.
Advantages and disadvantages of cultured yeast
Fast, consistent, lower levels of volatile acidity, large selection available
Less complexity and similarity of fruit expression, added cost
Name 3 types of fermentation vessel and 1 advantage and disadvantage of each
Stainless steel - impermeable, easily controlled, easy temp control, —- substantial investment
Concrete - high thermal inertia, can set up convection currents —- are harder to clean, cant move once set up
Wood - Can add flavours, allows ingress of oxygen (can be disadvantage), inexpensive over long term —- hard to clean and can harbour bacteria
Name the outcomes of MLC (MLF)
Reduction in acidity and rise in pH
Some colour loss in red wines
Greater microbial stability
Modification of flavour
Name 2 ways of removing alcohol post fermentation
Reverse osmosis
Spinning cone
What can be added to wines post fermentation to add colour?
MegaPurple
Name the unit of microoxygenation
mg/L per month
Benefits of micro-oxygentation?
Colour stability and intensity, softening of tannins, improving texture
Name the different aspects of wood that can affect how a wine will taste. 5 points.
Size of the vessel Type of wood Age of the vessel Production of the vessel (toasting and seasoning) Length of time in wood
Length of time on lees to give texture and autolytic character?
Texture - 9 months
Autolytic flavours - 15 months
What type of blendings can be done? (4 Vs)
Different varieties
Different vineyards
Different vintages
Different “vats”
Why would blending be done? (7 points)
Balance Consistency Style Complexity Minimise faults Volume Price
Types of post-fermentation clarification? 4 points
Sedimentation
Centrifugation
Fining
Filtration
Name the three catagories of common fining agents
Those that remove unstable proteins
Those that remove phenolics that contribute undesirable colour and bitterness
Those that remove colour and off-odours
Define a colloid
Microscopic particle to small to be removed via filtering
Name a fining agent that removes unstable proteins
Bentonite
Name 2 fining agents that can remove harsh phenolics
Egg white, Isinglass, Gelatine, Casein
Name a fining agent that removes colour and off odours
Charcoal
Name the 2 main types of filtration
Depth & Surface filtration
Describe a depth filter and 2 materials used
A depth filter traps particles in the depth of the material, it does not block easily but can allow small particles through when pressure is applied.
Diatomaceous earth, Sheet Filters
Name 2 types of surface filtration
Membrane filters, Cross-flow filters
Give a definition of a membrane filter
Membrane filters catch particles that will not go through the pore size, often <1micron. It is often used to make a wine microbial stable but can be easily blocked and the cartridges are expensive to replace.
How is protein stability achieved?
Fining with bentonite
Name 3 ways of achieving tartrate stability and a brief word on each
Cold stabilisation - wine held at -4 for around 8 days for crystals to form. Colloids must be removed before this process. There is a cost is cooling. Doesn’t remove calcium tartrate
Contact Process - quicker, continuous, cheaper, reliable than cold stabilsation. Potassium bitartrate is added to the wine and speeds the cystallisation process
Electrodialysis - A charged membrane is used to remove selected ions - high initial investment, can remove all ions.
Name 2 methods of obtaining microbial stability
Surface filtering (sterile filtering) Adding sorbic acid
Generally what are the ranges for free SO2 in red, white and sweet wines?
white - 25-45 mg/L
red - 30-55 mg/L
sweet - 30 - 60 mg/L
Name the 9 types of wine faults and their indications
Cloudiness/Haziness
Tartrates - (some consumers) (small tartrate cyrstals)
Re-fermentation in bottle - (small bubbles + haze)
Oxidation - (browning, loss of fruit, vinegar)
Cork taint - ( wet cardboard)
Volatile Acidity - (nail varnish/vinegar)
Reduction - (rotten egg aromas)
Light strike - (dirty drains armoas)
Brettanomyces - (animal, farmyard smells)
What are the key ways to avoid Brett?
Excellent hygiene
maintain effective SO2 levels
Keeping pH low and keeping the period between fermentation and malo as short as possible.
What makes up the total package of oxygen?
The amount of dissolved oxygen
Oxygen in the head space (greatest contributor)
Amount of oxygen in the cork
Oxygen transmission rate (OTR) of closure
Name 3 advantages and disadvatages of glass bottles.
It is inert and conveys no taint to the wine
It is inexpensive to manufactor and comes in a range of colours
It is best suited to allow bottle ageing
Has a high carbon footprint
Fairly fragile
Glass bottles are rigid allowing for oxidation once open.
Name the country where bag in box is very successful
Sweden
Name the 5 main types of closure
Natural cork Technical corks Synthetic closures Screwcap Glass stoppers - Vinolok
Name the compound that creates cork taint
TCA (2,4,6-trichloroanisole)
List the approaches taken to reduce cork taint
Cleaning with steam extration
More rigorous quality control during production
polymer barrier between cork and wine
closures from recomposed cork (technical cork)
What is the HACCP approach?
Hazard Analysis of Critical Control Points
Who are the ISO and what do they do?
International Organisation for Standardisation - they audit winerys to give assurance all the way down the supply chain in terms of quality control and safety.
What are the advantages of shipping in bulk? (5 points)
More Ecofriendly
Greater thermal inertia so less fluctuation of temp
Strict quality control
Wine can be adjusted at point of bottling
Shelf life can be extended
What is the main advantage to bottling on site?
Complete control over the product
What are the disadvantages of bottling on site?
More expensive and less eco friendly
Potentially lower shelf life as bottled earlier.
On what type of white varieties are most likely to use some skin contact and why?
Aromatic varieties as they have more aroma compounds in the skins.
What percentage of suspended solids will a winemaker try to achieve in a white grape must?
0.5-2%
Hyperoxidation is better suited to what type of white varieties
Non-aromatic
What temperature would sedimentation usually take place?
4 degrees
Name two disadvantages of lees stirring
It allows oxygen ingress by opening the bung
It is labour intensive
Name the different ways of concentrating sugar within a grape
Drying grapes on/off the vine
Noble rot
Freezing
Name the 3 factors that affect extraction of tannins and colour
Temperature, Time on the skins, The medium in which the extraction is taking place (must/wine)
Name the gas that facilitates the combination of tannins and colour
Oxygen, promotes colour stability
Name the two types of pre-fermentation macerations using heat & the temperatures/time used for each
Thermovinification - 50-60 degrees C - minutes to hours
Flash détente - 85-90 degrees - few minutes (cooled by vacuum)
Name the 5 types of cap management and list them from most gentle to most extractive
Pumping over Punching down Ganimede tanks Rack and return Rotary fermenters
Name 2 other maceration options winemakers may use during fermentation
Must concentration - drawing off juice before fermentation to concentrate remaining structural components and flavours
Co-fermentation - usually up to 5% of white
Name the 3 types of whole bunch fermentation for red wines
Carbonic maceration
Semi carbonic maceration
Whole berries/bunches with crushed fruit
What are the 3 main ways of producing Rosé?
Direct pressing
Short maceration
Blending
