Vinification Flashcards
In white wine making, why is skin contact limited?
To reduce the risk of oxidation
What process do some white winemakers choose to limit the contact between skin and juice and to, arguably, make a wine with more purity and delicacy?
They load the press with whole bunches of uncrushed grapes. The process is gentle, reduces risk of oxidisation and can, potentially, lead to wines with more purity & delicacy.
List, in order, the minimum (always present) flowchart steps that must happen to make White Wine.
- Grapes pressed and skins extracted (or pressed as whole bunches)
- Juice clarification (can be optional)
- Alcoholic fermentation (54-71F)
- Rack off Gross Lees
- Newly made wine
- Packaging and offered for sale
What can happen if white grape juice isn’t clarified before fermentation?
It can result in creation of unpleasant aromas and fermentation could stop prematurely.
What is the fermentation temperature range for white wine?
12c-22c / 54-72F
What are the 4 methods to clarify grape juice or finished wine?
Settling
Centrifugation
Fining
Filtration
What happens if wine is fermented at too low a temperature?
Creation of pear drop aromas and can fail to capture varietal fruit characters.
What happens if wine is fermented at too high a temperature?
Can encourage more complex non fruit aromas to develop BUT risks losing losing varietal fruit aromas.
Name 3 choices for a white wine maker after fermentation.
- Mature in oak or inert vessels (with or without Oak staves or chips).
- Omit or keep the fine lees to add texture and flavour to the wine.
- Allow or block MLF
Describe MLF and what does it achieve in wine?
MLF = Malolactic fermentation
Takes place once alcoholic fermentation has finished
Converts tart Malic acid (also found in apples) into softer Lactic acids (also found in milk).
Result softens and reduces acidity and creates buttery flavours and CO2
How can a winemaker discourage MLF?
Dropping to cooler temperature, adding SO2, or by filtering out bacteria.
How can a winemaker encourage MLF?
Raising the temperature of the wine, not adding SO2, adding malolactic bacteria.
Why might a winemaker blend the wine?
Improve consistency, enhance the balance of the wine, and/or create a certain style.
What is RCGM and what is it used for?
RCGM = Rectified Concentrated Grape Must
= Unfermented grape juice
Used to increase sweetness in the finished wine
In sweet winemaking, name 6 methods that result in sweeter wine
- Stopping fermentation by Fortification, by adding high dose of SO2, or chilling the fermenting wine (must then be filtered).
- Adding a sweetening component such as Süssreserve or RCGM
- Concentrating grape sugars
3a. Using grapes affected by Noble Rot
3b. Drying grapes on the vine (become like raisins) ‘Passerilage’
3c Drying grapes after picking ‘Passito’ (in Italy) delivers ‘Recioto’ wine
3d. Freezing on the vine ‘Eiswein’ or ‘Ice Wine’.
What does ‘Cold Maceration’ or ‘Cold Soaking’ mean and what does it achieve?
After crushing grapes, macerate with skins at low temperature before fermentation starts.
The purpose of this maceration is to extract colour and flavour compounds. Tannins are more soluble in alcohol (not water), and are not extracted here.
At what temperature range is red wine usually fermented?
20-32c / 68-90F
Above 35c/95F may kill the yeast.
What is ‘Cap Management’ and what does it achieve?
The ‘Cap’ is the mass of pulp and skins on the surface of the wine, if left to float little colour, flavour or tannin will be extracted.
‘Cap Management’ is one of the processes to to keep the pulp and skins in contact with the fermenting juice.
List 4 ‘Cap Management’ techniques and briefly outline what they are.
Punching Down - Punching the Cap down by hand with paddles on sticks, more latterly done by mechanical paddles.
Pumping Over - Fermenting juice drawn from bottom of vat and pumped up on to the top to wet the Cap.
Rack and Return - Fermenting juice drained into another vessel then pumped back over the Cap.
Rotary Fermenters - Fermentation takes place in rotating horizontal tanks keeping juice in constant contact with skins.
What is ‘Post-fermentation Extraction’?
Maceration after fermentation encourages further extraction of tannin which may or may not be desirable. Some winemakers believe it results in smoother tannin structure.
What is ‘Press Wine’ and what is it used for and what are ‘press fractions’?
When maceration has finished, the ‘free run’ wine is drawn off the skins then the remaining mass is pressed creating ‘press wine’.
Early pressings are much the same as the free run wine but with more pressure the ‘free run’ gets progressively darker - press fractions.
Later press fractions may be used to adjust colour and tannin in the final blend.
What is the purpose of ‘Whole Bunch Fermentation’?
The use of whole bunches of uncrushed grapes in the fermentation varying from a small % to the entire vat. The objective being to create an oxygen free environment for the uncrushed fruit.
The berries create some alcohol in their cells without yeast referred to as ‘Intracellular Fermentation’.
A range of distinctive fruity aromas is created in the berry which gives wines, made this way, unique qualities, full fruit, kirsch, and bubble gum.
Three Types: Carbonic/Semi-Carbonic/Whole cluster with crushed fruit
Name and briefly summarise 3 methods of ‘Whole Bunch Fermentation’.
Carbonic Maceration - Placing whole uncrushed bunches into vats that are filled with CO2 to remove oxygen. Intracellular Fermentation starts and at 2% ABV the skins split releasing juice. Then usually pressed and yeast then complete fermentation. Method extracts colour but little tannin, wines are soft and fruity with notes of Kirsch, bubblegum and cinnamon like spice.
Semi Carbonic - Similar to Carbonic but vats not filled with CO2. Vats filled with whole bunches, top ones crunch bottom releasing juice. Ambient yeast ferments juice which creates CO2, intact berries undergo Carbonic Maceration. Can result better grape aromas.
Whole Bunches with crushed fruit - Whole bunches mixed with crushed grapes, no CO2 but bunches blanket crushed grapes keeping out oxygen so intracellular fermentation takes place.Technique thought to give wine silkier texture and brighter fresher fruit character.
What are the 4 most common black grape varieties for high-volume wine making and why are they most suitable?
Cab Sav, Merlot, Syrah/Shiraz & Grenache/Garnacha
Because the regions responsible for high-volume wines tend to be warm, sunny and dry and due to the concentration of colours, tannins and flavours, in their skins, they can deliver fruity wines with adequate colour even at high yields.
Generally, at what temperature will high-volume red wines be fermented at and why?
22-25c / 71-77F with commercial yeast.
The lower temperature will help maximise fresh fruit flavour.
For premium wines, what is the usual fermentation temp range for Cab Sav and why?
Generally 26-30c / 79-86F being warm enough for sufficient extraction yet cool enough to promote fresh fruit flavours.
What is a ‘Natural Wine’?
A wine that is made with minimal intervention
Oxygen during wine making is?
Always positive.
Always negative.
Sometimes positive and sometimes negative.
Has no impact on the final wine.
Sometimes positive and sometimes negative
Which one of these is FALSE about using Sulphur dioxide in wine making?
SO2 Levels are limited because it can be toxic at very high levels.
It is an antioxidant
It is used to adjust the acidity of wine.
It’s an antiseptic
It is used to adjust the acidity of wine.
Which is not often part of anaerobic wine making?
Maturing wines in old oak barrels.
Use of antioxidants on the grapes during picking.
Picking at night when the temperatures are low.
Filling airtight equipment with Carbon Dioxide or Nitrogen.
Maturing wines in old oak barrels, b/c oak lets in oxygen.
Protective wine making is most likely to result in wines that are:
Oaky.
Complex.
Fruity in Style.
Age worthy.
Fruity in Style.
What is the best method of storing anaerobic made wines?
In the stomach of your tutor.
In an inert stainless steel tank or epoxy resin lined cement tank.
In an oak barrel
In a bottle with a plastic cork.
In an inert stainless steel tank or epoxy resin lined cement tank.
Which is an INCORRECT statement?
The bigger the barrel the slower oxidation occurs.
All other things being equal, the smaller the barrel the quicker the oak flavour is imparted.
A 225 Litre barrel is small.
Large barrels oxidise faster because of their greater surface area.
Large barrels oxidise faster because of their greater surface area.
Which wine is not made by leaving a gap at the top of a barrel?
Rutherglen Muscat
Olorosso Sherry
Champagne
Tawny Port
Champagne
Which tertiary flavours are a result of excess oxidation during maturation?
raspberry, toffee, nuts
caramel, toffee, nuts
caramel, coffee, tar
raspberry, toffee, tar
caramel, toffee, nuts
Which one of these is not a sign that a wine has become exposed to too much oxygen?
White wines get darker.
Red wines get lighter.
Wines lose their fresh fruit flavour.
Bacteria will cause the wine to lose acidity, develop buttery flavours and become fizzy.
Bacteria will cause the wine to lose acidity, develop buttery flavours and become fizzy.
Which material will not impart an oak character to the wine
Staves.
Oak chips.
Oak barrels.
Epoxy resin lined tanks.
Epoxy resin lined tanks.
Which one of these is not an inert vessel?
Epoxy lined concrete tank
Stainless steel
A Glass bottle with a screw cap
Oak barrel
Oak barrel
What is the correct order for Grape Processing?
Sorting, Destemming & Crushing, Pressing, Adjustments.
Sorting, Pressing, Destemming & Crushing, Adjustments.
Adjustments, Sorting, Destemming & Crushing, Pressing.
Pressing, Destemming & Crushing, Adjustments, Sorting.
Sorting, Destemming & Crushing, Pressing, Adjustments.
Which one of these is not required if the grapes are mechanically harvested?
Adjustments.
Sorting.
Pressing.
Destemming & Crushing.
Destemming & Crushing: machine-harvested grapes have been shaken from their stems.
In the image below, in red wine making what does the A represent
Crush
