Vinification Flashcards
Which statement about Malolactic Fermentation MLF is false?
The bacteria is sensitive to SO2 and can be stopped by it.
Lowers the perceived acidity in a wine by converting the crisp malo acid to softer lactic acid
Can suppress the varietal purity and can add butter, hazelnut flavours
All white wines and most reds undergo MLF
All white wines and most reds undergo MLF
RCGM means?
Rectified Concentrated Grape Must and it is used to adjust the residual sugar level in commercial wines.
Because it is a product of wine it is legally allowed in many countries to be added back to a wine.
What are the three ways to make Rosé wine?
Briefly summarise them
Direct Pressing - Grapes crushed and pressed (as for white wine) being careful not to press too hard. Fermented cool as for white wine. Used for delicately coloured Rosés
Short Maceration - Grapes crushed and allowed short maceration. Free run juice drained and fermented at low temp as for white wine. Produces darker Rosés.
Blending - Small amount red wine added to white. In EU only permitted in Champagne. Some fruity inexpensive New World Rosés made this way
What is the correct order for typical red wine production?
Crush, press, ferment, maturation, bottling
Crush, ferment, press, bottling, maturation
Crush, ferment, press, maturation, bottling
Crush, Ferment, maturation, press, bottling
Crush, ferment, press, maturation, bottling
What is RCGM and what is it used for?
RCGM = Rectified Concentrated Grape Must
= Grape must that has had its non-sugar components eliminated.
Used to
- increase sweetness in the finished wine
- increase alcoholic potential of wine (chaptalization)
Vinification is defined as:
-The process and decisions made by winemakers IN the winery that affect quality and style of wine.
What are the 4 human factors affecting style, quality and price of wines?
Grape growing
Winemaking
Maturation
Market forces
What happens if white wine is fermented at too low a temperature?
Creation of pear drop aromas and can fail to capture varietal fruit characters
How would you acidify grape juice?
Add Tartaric acid
How is acidification normally carried out?
Where is this normally done?
By the addition of tartaric acid in powder form.
Common in many warm and hot regions around the world. In Europe, it is only permitted in warmer regions.
List the 3 methods of clarification
Sedimentation (Racking)
Fining
Filtration
- depth filtration
- surface filtration
Which one of these is not a method used in anerobic winemaking?
Use of SO2 at harvest time
Picking at night when it is cooler
Fermentation in Stainless Steel
The use of specially cultured yeast strains
The use of specially cultured yeast strains
A friend opens a bottle of wine and discovers what looks like glass in the bottom of the cork.
What are these, actually?
What is their presence an indicator of?
Tartrate crystals.
Indicates that the wine has not been cold-stabalized.
Below ____, yeasts will remain inactive.
Above ____, yeasts will die.
50o F
113oF
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 happens if white wine is fermented at too high a temperature?
Can encourage more complex non fruit aromas to develop BUT risks losing losing varietal fruit aromas.
Which statements about blending are true?
1) Blending of grape varieties is common
2) Blending of vintages is allowed in some regions.
3) Blending can occur at any stage of the winemaking process
4) Blending of different pressing fractions can help balance.
1 only
1 & 2
1, 2 & 4
1, 2, 3, 4
1, 2, 3, 4
MLF stands for?
Malolactic Fermentation.
What is MLF and what does it achieve?
MLF = Malolactic fermentation
Takes place once alcoholic fermentation has finished
Converts tart Malic acid (found in apples) into softer Lactic acids (found in milk).
This softens and reduces acidity, rounds out a wine’s texture and creates buttery (diacetyl) flavours.
Protective wine making is most likely to result in wines that are:
Oaky.
Complex.
Fruity in Style.
Age worthy.
Fruity in Style.
Adding an Alkali will?
Increase the acidity in the wine or must
Decrease the acidity in the wine or must
increase the tannins in the wine or must
decrease the tannins in the wine or must
Decrease the acidity in the wine or must
How would you de-acidify grape juice?
Addition of various alkali
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 crush 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.
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.
Sedimentation is?
When large particles settle at the bottom of the tank and the wine is decanted off.
Sterile filtration is
1) Not necessary for fortified wines.
2) A surface filter with pore size small enough to remove yeast and bacteria.
3) Is not required for low acid, sweet wines that have not undergone MLF.
4) A filter whose pores can block up easily.
1,2,3 & 4
2, 3 & 4
1, 2 & 4
1, 3
1, 2 & 4
List 4 considerations during white wine making
Skin contact
Clarification
Fermentation temperature
Choice of vessel
- Inert
- Inert (+ Oak)
- Barrels
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, and to limit skin contact, which imparts tannin and color.
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.
Give 5 reasons why you might blend wine
Balance
Consistency
Style
Complexity
Price
What is ‘Post-fermentation Extraction’?
What is a specific example of a wine/style that utlizes this technique?
Maceration after fermentation encourages further extraction of tannin which may or may not be desirable.
Some winemakers believe it results in smoother tannin structure.
Very common with tradional Barolo producers.
Why is sorting grapes an important part of the vinification process?
- Necessary to remove excess leaves, branches, damaged fruit, MOG
- sorting can be done by hand, either cluster by cluster or by selecting single grapes from clusters
In Sweet winemaking name 6 methods that result in sweeter wine
i. Stopping fermentation by Fortification, by adding high dose of SO2 or chilling the fermenting wine (must then be filtered).
ii. Adding a sweetening component such as Süssreserve or RCGM
iii. Using grapes affected by Noble Rot
iv. Drying grapes on the vine (become like raisins) ‘Passerilage’
v. Drying grapes after picking ‘Passito’ (in Italy) delivers ‘Recioto’ wine
vi. Freezing on the vine ‘Eiswein’ or ‘Ice Wine’.
Which of these are reasons that Alcoholic fermentation may stop?
1) The sugar is consumed
2) The temperature is above 35℃
3) The yeast runs out of Nutrients
4) The sugar and alcohol level is too high.
1, 2, 3, 4
1 only
1, 2, 4
1, 2, 3
1, 2, 3, 4
List, in order, the minimum steps that must happen to make White Wine
- Grapes pressed and skins extracted (or pressed as whole bunches)
- Juice clarification
- Alcoholic fermentation
- Rack off Gross Lees
- Newly made wine
- Packaging and offered for sale
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
Name 3 tertiary flavours are a result of excess oxidation during maturation?
caramel, toffee, nuts
To prevent MLF from occuring, temperature and SO2 levels should be:
Temperature: Low
SO2: High
What are necessary elements for a wine to be able to age well?
High tannin
High Acidity
High alcohol
Which one of these is NOT a flavour associated with oak barrels?
Cloves
Toast
Leather
Vanilla
Leather
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.
Which one of these is wrong 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.
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
For premium wines what is the usual fermentation temp range for Cab Sav and why?
Generally 79~860F, being warm enough for sufficient extraction yet cool enough to promote fresh fruit flavours.