Winemaking Flashcards
(132 cards)
1
Q
What are Anti-oxidative Phenolic Compounds
A
Compounds found in red wine that slow oxidation
(Phenolic compounds in red wines have an anti-oxidative effect, which means that they can absorb more oxygen before oxidation effects are perceptible)
2
Q
How long does wine generally spend in pre bottling maturation (red and white)
A
White wine - 6-12 months
Red wine - 12-24 monthss
3
Q
What is Ullage
A
Headspace within a container that allows the wine to come in contact with oxygen.
Can be filled with inert gas (nitrogen, carbon dioxide, argon) to prevent/slow oxidation.
4
Q
How does wine get oxygen exposure during maturation
A
Racking,
Lees stirring,
Topping up.
Whenever the bung is removed.
5
Q
What are the effects of Micro-oxygenation
A
- Colour stability and intensity
- Soften tannins
- Improve texture
- Herbaceous flavours (lessen)
- Oxygen exposure. Gentle controlled, quick and cheaper than barrel aging.
Integrate any oak alternatives used (chips, staves).
6
Q
Lactones
A
Compounds that give American oak the aromas of coconut.
7
Q
What and how - Reduction (fault)
A
Rotten egg smell that comes from high levels of hydrogen sulphide.
Fault from uncontrolled/unmonitored ageing on gross lees.
Bottling without sufficient oxygen or ingress via closure.
8
Q
What might differ about wines that are blended together
A
- grape varieties
- locations (from different vineyards, different regions or even different countries)
- grape growers or businesses that sell grapes, must or wine
- vintages
- treated differently in the winery (e.g. wine made from free run juice and wine made from press juice, or wine matured in oak with wine that has been stored in stainless steel or concrete)
- equally in the winery but are in different vessels for logistical reasons (e.g. unless a wine is made in very small quantities, wine fermented or matured in barrels will need to be blended together to make up the required volume).
9
Q
Key reasons for blending wines
A
Balance – Blending may help to increase or moderate the levels of certain characteristics of the wine to produce a wine that is better balanced, and in this way enhance quality. (Merlot in Bordeaux provides body and ripe, plummy fruit to a blend with Cabernet Sauvignon, which can be too astringently tannic if not fully ripe)
Consistency – Across vintage or many years depending on wine style (Sherry and non-vintage sparkling wine, inexpensive wines).
Style – ‘house style’ or required style (rose)
Complexity – The blending of two or more parcels of wine may lead to a greater range of flavours.
Minimise faults – If wine in one barrel is showing significant volatile acidity (see Faults), that wine may be sterile-filtered to remove acetic acid bacteria and then blended into a larger volume of un-faulty wine. Lower concentration and sensory perception of Acetic Acid.
Volume – Blend the wines from different small vineyards to produce viable volumes of certain wines, or in poor vintages where yields are low.
Price – Include cheaper grapes along with more well recognised expensive grapes - eg Chardonnay and Trebbiano.
10
Q
Bottling day checklist
A
4 months to 8 weeks ahead - Assemble final blend
Full chemical analysis – alcohol, residual sugar, free SO2, etc.
8 weeks ahead - Final adjustments: alcohol, acidity, tannins if desired
6 weeks ahead - Protein stability trial and if necessary fine with bentonite
4–6 weeks ahead - Test for tartrate stability and, if necessary, treat - 4 weeks ahead
Check protein stability and tartrate stability again, treat as necessary
1–2 weeks ahead - Add sweetening agents e.g. grape concentrate, if using (for mouth feel and finish)
72–48 hour ahead - Test filterability of wine
24 hours ahead - Adjust free SO2
Bottling day - Adjust dissolved oxygen and CO2
During bottling - Check dissolved oxygen (to ensure no pickup) and SO2 levels regularly and keep sample of bottle wines for quality assurance purposes
11
Q
Three categories of fining agents
A
- Remove unstable proteins
- Remove phenolics that contribute undesirable colour and bitterness
- Remove colour and off-odours.
12
Q
What are tartrates
A
Harmless deposits of crystals that can form in the finished wine
potassium bitartrate
calcium tartrate (less common)
13
Q
How to treat Brettanomyces in wine
A
Brettanomyces is a problem, wine can be treated with DMDC (dimethyl dicarbonate, commercial name: Velcorin)
14
Q
What are the generally allowed amounts of SO2 before bottling
A
White wine: 25–45 mg/l (lower than for red wines due to lower pH)
Red wine: 30–55 mg/l
Sweet wine: 30–60 mg/l
15
Q
What is sparging
A
Flushing wine with an inert gas to remove oxygen (done before bottling).
16
Q
What causes cork taint and how does it affect the aroma/flavour of the wine
A
TCA (2,4,6-trichloroanisole).
- Unpleasant smell of mould or wet cardboard
- Suppresses the fruit character.
17
Q
What is OTR
A
Oxygen transmission rate. Refers to how permeable wine bottle closure is.
18
Q
What aromas do volatile reductive sulphur compounds give in wine
A
Low levels - aromas that may be perceived as positive, such as struck match and smoke.
High levels they give rotten egg (always a fault) and other unpleasant aromas.
19
Q
What does HACCP stand for and mean
A
HACCP (Hazard Analysis of Critical Control Points):
Identify each hazard and what can go wrong. The state how serious the hazard is, how it can be prevented and how it can be corrected.
20
Q
What is a Flexitank
A
A single-use, recyclable polyethylene bag that fills a standard container for bulk shipping of wine.
21
Q
Purpose of skin contact in white wine production
A
- Extraction of aroma and flavour compounds and precursors.
- Improve texture of the wine by extracting a small amount of tannin.
22
Q
Why would winemakers choose to press whole bunch, uncrushed grapes.
A
- Limit skin contact
- Reduce risk of oxidation
Typical for wines requiring: - Early drinking
- Delicate fruity flavours
- Minimal colour
- Smooth mouthfeel.
23
Q
How are Orange Wines made and what is their flavour profile
A
Amber (orange) coloured wines that are fermented on their skins without temperature control or SO2 added. The colour develops due to the oxidation of compounds extracted from the grape skins.
Flavour profile:
- Dry
- Notable levels of tannins
- Mainly tertiary characteristics (nuts and dried fruit).
24
Q
Define Free Run Juice and describe it’s characteristics
A
The juice that can be drained off the press as soon as the grapes are crushed.
(whole bunches, destemmed)
Characteristics:
Lowest levels of solids, tannin and colour of the
Highest acidity and sugar.
25
What are Press Fractions
Juice from different stages of pressing (free run is the first)
Different press fractions may be blended later in the winemaking and maturation process.
The last press fractions too generally astringent or bitter (due to phenolic compounds from the skins, seeds or stems) to use.
26
What esther gives a banana like smell
Isoamyl Acetate
27
What is the French term for lees stirring
Bâtonnage
28
What are the conditions for Noble Rot and how does it affect the grape.
- The grapes must be fully ripe.
- Humid, misty mornings followed by sunny, dry afternoons.
- Damp conditions in the morning allow rot to develop on the grapes.
- The fungus punctures the grape skin with microscopic filaments, leaving tiny holes in the skin.
- Warm sunny afternoons slow the rot and cause water to evaporate from the grape.
- Modifies aroma compounds in the grape adds flavours. Honey, apricot, citrus zest, ginger and dried fruit.
29
Define cryoextraction in terms of ice wine and advantages/disadvantages
Picking grapes as usual and then freezing them at a winery.
Advantages:
- Does not entail the risks of leaving the grapes on the vine into late autumn or winter.
- Lessens risk of yield loss to disease or pests.
- Much cheaper than traditional production.
Disadvantages:
- The terms Eiswein and Icewine cannot be used on the label.
- Energy to freeze the grapes.
30
How is fermentation interrupted
- Chilling to below 10°C (50°F)
- And/or add a high dose of SO2 to inhibit the yeast.
- Rack off its sediment and sterile filter to ensure fermentation does not start again
31
Which winemaking processes cause red wine to lose colour (anthocyanins)
- Lees aging
| - Addition of SO2
32
What is pigeage
Punching down
33
What is remontage
Pumping over
34
What is delestage
Rack and return
35
What is saignée
Must concentration
36
What flavours does whole berry/bunch fermentation add to red wine
Kirsch, banana, bubble gum and cinnamon.
37
Kinds of depth filtration
Depth filtration: Not absolute. Use a porous filtration medium to retain particles throughout the medium, rather than just on the surface.
* Diatomaceous earth - traps particles in the material. Filters must or lees,
- Rotary vacuum filters. Oxidative
- Enclosed filters can be flushed with inert gas
- Comes in range of particle sizes large->small
- Must be disposed of responsibly once used.
* Sheet filters (yeast and bacteria) - 'plate and frame' / 'pad'. Wine passed through sheet of material - more sheets = quicker filter. Fine sheets remove yeasts at bottling.
- Expensive initial investment
- Sheets are cheap.
- Trained labour
38
Kinds of surface filtration
Surface filtration: Absolute. Particles greater than the pore size of the filter on the filter surface
Membrane filters - Very small pores (<1 micron). Must be filtered by depth filtration first to prevent blockage. Final filtration before wine is bottled (filters out yeasts and bacteria - micro biologically stable)
Cross-flow (tangental) filters - wine passes through filter whilst cleaning the surface. Filter high load very quickly, no filter material to buy. Expensive (large + high value wines).
39
Why would a winemaker choose not to filter
Negatively affects wine's character, strips it of it's texture.
40
Argument against not filtering
- 'Filtration shock' - wine recovers after a few months.
| - Correctly fined wine expresses fruit and terroir better.
41
What should wine be fined with to ensure protein stability
Bentonite
42
What are tartrates
Harmless crystal deposits that form in finished wine:
- Potassium bitartrate (common)
- Calcium tartrate (less common)
Many customers regard this as a fault.
43
What three kinds of stabilisation should a winemaker consider
- Protein stability
- Tartrate stability
- Microbiological stability
44
What is microbiological stability and how is this achieved
Lactic acid and Brettanomyces can live in the bottle and withstand ph and alcohol levels in wine.
Wines with residual sugar and wines that have not gone through complete malolactic conversion are particularly at risk.
Wines that have not had malo completed run the risk of it occuring in the bottle (a fault)
Treatments
- Sorbic acid - low levels can be detected by some people.
- SO2
- Sterile filtration (fine enough to remove yeast and bacteria)
45
Options for ensuring tartrate stability
Potassium bitartrate and Calcium tartrate
- Cold stabilisation - Held at -4C for 8 days so crystals form, then filtered out. Traditionally happens when wine is kept in cold cellar for months in winter. Colloids must be fined out first, removes PT not BT. Cost of refrigeration equipment and power.
- Contact process - Potassium bitartrate added to wine, seeds crystal formation. Cooled to 0c for 1-2 hours. Crystals filtered out. Quicker, more reliable and cheaper.
- Electrodialysis - Charged membrane to remove selected ions. High initial investment, total costs lower (less energy, faster).
- Ion exchange - Replaces potassium and calcium ions with hydrogen or sodium ions preventing them dropping out of wine. Not allowed in some places as sodium = bad.
- CMC (Carbomethylcellulose) - Extracted from wood. Prevents tartrates developing to visible size. Used on inexpensive red or rose but red wines = tannins = haze. Stability for a few years, much cheaper than chilling.
- Metatartaric acid - Prevents growth of crystals. Compound is unstable and loses effect over time and at high temperatures (25-30C). Quick and easy used for inexpensive red wines.
46
What can a wine maker do just before bottling (finishing)
- Adjust levels of SO2: Depends on ph level and intended drinking period.
- Reduce dissolved oxygen: Can accellerate aging speed and reduce shelf life. Removed by sparging.
- Add carbon dioxide: Added in for extra freshness (inexpensive fresh white + rose wine)
47
What are the normal levels of free SO2 in wine
- White - 24/45 mg/l
- Red - 30-55mg/l (lower PH requires less)
- Sweet - 30-60ml/l
48
List main wine faults (9)
* Cloudiness and hazes
* Tartrates - Most inexpensive + mid priced wines are stabilised but sometimes not successful.
* Bottle refermentation - cloudiness, bubbles or spritz. Failure to stabilise and clarify/filter.
* Cork taint - Mouldy, wet cardboard smell, reduces fruit and shortens wine finish.
* Oxidation - Faulty bottling, poor quality corks or closures, keeping wine for too long not ment for again. Brown in colour, no primary fruit, vinegar.
* Volatile Acidity (vinegar) - nail varnish / vinegar. Acetic acid bacteria, inadequate SO2, oxygen exposure. Avoided by excluding damanged grapes, hygiene in winery, avoiding ullage, careful racking, SO2.
* Reduction - volatile reductive sulfur compounds. Stuck match -> onion & rotten eggs.
* Light Strike - UV radiation / visible light. Florescent lighting, light coloured glass. Dirty drains. Volatile sulphur compounds.
* Brettanomyces - Animal, spicy, farmyard smells. Can add complexity at low level, fault at high level - off flavours dominate, fruit is reduiced and acidity / tannin becomes prominent.
49
How does Brettanomyces affect the wine and how should it be treated
Gives Animal, spicy, farmyard smells. Can add complexity at low level, fault at high level - off flavours dominate, fruit is reduiced and acidity / tannin becomes prominent.
Avoid by:
- excellent hygiene
- maintaining effective SO2 levels
- keep PH levels low
- keep period between fermentation and malo short so SO2 can be added ASAP.
Treat with:
- Velcorin (DMDC - dimethyl dicarbonate)
50
Main considerations when selecting wine packaging and closures
* Oxygen management
* Place in the market
- early sale
- aging + long life
* Markets in which it will be sold.
51
Effects of too much or too little oxygen when packaging wine
Too little:
- reductive sulphur compounds develop
Too much:
- premature browning + oxidised characteristics.
52
What is 'total package oxygen' in wine
- Oxygen dissolved in the wine
- Oxygen in head space (most)
- Oxygen transmission rate (OTR) of the closure.
53
Wine is the overwhelmingly preferred opition for packaging wine. What are the exceptions:
- Producer markets (france) winery PVC jerry cans (short term storage & early drinking)
- Sweden - Bag-in-box > 50%
54
Advantages and disadvantages of glass for packaging wine
Advantages:
- Inert, no taint
- Sterilised before arrival at winery
- Inexpensive to manufacture. Many colours.
- 100% recyclable (some colours easier than others)
- Impermeable to oxygen, best material for aging.
Disadvantages:
- High carbon footprint (heat to manufacture)
- Heavy to transport (carbon footprint)
- Fragile
- Rigid, once open wine is subject to oxidation (c.f bag in box)
- Clear bottles at risk of light strike
55
Advantages of PET packaging
Suited to wines with a limited shelf life and quick consumption in informal settings (picnics, planes)
Advantages:
- Light
- Tough
- Inexpensive
- Recyclable
- Lined with an oxygen barrier = impermeable, reasonable shelf life
Disadvantages:
- Special equipment required to inflate bottles at filling.
56
Advantages/Disadvantages of Bag-in-box packaging
Advantages:
- Flexible pour size
- Range of sizes (1.5-20 litres)
- easy to store, low environmental impact
Disadvantages:
- Requires higher SO2 to counter oxidation
High quality tap required to reduce oxidation. Shelf life 6-9 months. Pioneered in Australia.
57
Advantages / Disadvantages of 'Brick' packaging
Brick = Tetra pak
Paper card with plastic layers + aluminium foil layer to exclude oxygen and light.
Advantages:
- Can be entirely filled wine wine, eliminating oxygen.
- Accepted by consumers at lower price points
Disadvantage:
- Filling equipment expensive (outsourced)
Popular in Germany where price is a major driver.
58
Pouch packaging
Similar to bags inside goon boxes. 1.5 litre or single serve size.
59
Advantages / Disadvantages of 'Can' packaging
Used for wine to be consumed early.
Advantages:
- Light weight
- Robust
- Easy to open
- Impermeable to oxygen
- Recyclable
Disadvantages:
- Must be lined with plastic to avoid being attacked by wine acidity.
- Filling equipment very expensive (outsourcing)
60
Ideal characteristics of a wine closure:
- Protect from oxidation
- Inert
- Easy to remove and reinsert
- Cheap, recyclable and free from faults.
61
Cork length
Shorter corks - cheaper
| Longer corks - more expensive- less oxygen ingress - suitable for wines that will be aged longer.
62
Advantages of cork
Light, flexible, renewable, inert (apart from TCA).
63
Problems aging wine with cork
Different corks will naturally have different levels of oxygen ingress, so bottles will age at different rates.
64
Approatches to dealing with cork taint
Caused by TCA
- Cleaning closures with steam extraction
- Create closures from recomposed cork particles (cleaned + reconstituted with plastic).
- High tech solutions to check for TCA (gas cromatography)
- Add impermeable membrane between cork and wine
65
Agglomerated cork
A kind of technical cork where cork granules are glued together.
Available with different oxygen ingress rates.
66
One-plus-one cork
Cork with central agglomerate, disk of real cork at both ends.
Available with different oxygen ingress rates.
67
What are synthetic corks
Plastic corks (food grade) with silicone coating.
Moulded closures
- cheapest
- rigid, difficult to reinsert.
- Only suitable for a few months (oxygen)
Extruded closures
- more elastic
- firm layer of plastic around a plastic foam.
- variable oxygen ingress rate (top models maybe suitable for extended aging)
Flavour scalping - plastic absorbed some flavour molecules. May not be detected by consumer.
68
Screwcap
* Seal with tin (impermeable)
- Can become reductive after bottling
- Lower SO2 needed
* Saran (low permeability)
Market acceptance varies (++ NZ, Australia, -- USA, China)
69
Vinolok
Brand of glass stopper.
- Similar longevity to current closures but special bottles need to be used.
- Attractive
- Very expensive (super premium)
70
Ideal post bottling maturation conditions
- 10-15C,
- Cool dark place
- Constant temperature
- Undisturbed, no vibrations
- Constant humidity
If cork:
- On side so cork doesn't dry out and seal is maintained.
71
Three cleaning procedures for winery hygiene
- Cleaning - remove surface dirt
- Sanitation - water/detergent/sanitiser/steam reduce level of organisms to acceptable levels.
- Sterilisation - High strength alcohol/steam to eliminate unwanted organisms from high risk areas (bottling filler heads).
Wineries have a detailed cleaning schedule.
72
Quality control
Set of practices by a company that ensures a quality product.
73
Quality assurance
- The way a business organises itself to deliver a good product constantly and protect itself from legal challenge.
- Includes quality control.
74
HACCP
Hazard Analysis of Critical Control Points.
Identify possible hazards, state how serious it is, how to prevent and correct it.
75
ISO Standard Certification
International Organisation for Standardization
Give assurance to all parties down the supply chain (wholesaler -> retailers -> consumer).
Conduct external audits.
76
Traceability
A system in place for the winery to respond an investigate complaints about the wine. Can come from any point in the supply chain.
Consignment has unique lot number so company can trace back all aspects, investigate and keep samples of lots so they can compare with returned bottles.
77
Advantages and disadvantages of bulk shipping
Advantages:
- more environmentally friendly (24-26k bottles per container vs 9-10k of shipping in bottle)
- cheaper
- greater thermal inertia - less temperature fluctuation
- strict quality control (wine parameters measured at shipping and receiving - individual bottles could be heat damaged in transit).
- wine can be adjusted at point of bottling
- shelf life doesn't need to include shipping time (bag-in-box)
Disadvantage:
- loss of direct relationship with producer
- loss of local business and employment (South Africa protest)
- only viable for larger brands (3+ containers per year)
78
Advantages and disadvantages of bottle shipping
Advantages:
- entire product is controlled by producer
Disadvantages:
- smaller wine in one container, higher financial, environmental cost
- potential damage to wine from high and fluctuating temperatures
- quality control
- spoilage of labels and packaging
- shorter shelf life of inexpensive wine because it is bottled earlier.
79
ISO Tank
Stainless steel tank used for bulk shipping of wine. ISO Certified, reusable.
80
What is Skin Contact and what does it achieve in white winemaking.
- Leaving the juice in contact with the skins to extract compounds.
- Extraction of aroma and flavour compounds and precursors.
- Add small amount of tannin (enhance texture).
Too much = bitter and coarse.
81
Why would minimal skin contact be used in white wine
Majority of white wines made with zero or minimal skin contact. Aroma/flavour compounds in white grapes = pulp.
Minimal/zero for wines that require:
- Delicate fruity flavours
- Minimal colour
- Smooth mouthfeel
- Early drinking wines (no time to soften tannins)
- Under ripe fruit (not extract bitter/astringent tannins)
82
What kinds of white wine use skin contact
Lots of aroma compounds:
- Riesling
- Gewurztraminer
- Viognier
- Muscat
- Sauvignon Blanc
- Orange wine
(Enhances texture as not matured in oak)
83
Key factors of skin contact (White wine)
- Time (1-24+ hours)
| - Temperature (chilled to < 15C)
84
Why would whole bunches be pressed (white wine)
- Reduces oxidation (press can be flushed with inert gas)
- Gentle - low in solids tannins and colour
- Stems - break up grape skins, provide channels for wine to run through
- Expensive - fewer grapes fit in press, slower.
85
When is hyperoxidation used in white wine
- Neutral grape varieties (Chardonnay)
- Remove bitter compounds from grape skins
Reduces levels of volatile thiols and methoxypyrazines (would not be used in Sauvignon Blanc when a herbaceous style is required)
86
Advantages/Disadvantages of solids in white wine after clarification
Higher solids:
- Add texture
- Astringency (skin and stem particles)
- Complexity (greater range of fermentation aromas)
- Reductive sulphur compounds could develop in fermentation
- Premium Chardonnay
- Provides yeast nutrients
Lower solids:
- Fruity aromas (lack of yeast nutrients)
- Stuck fermentation (if very low)
- Inexpensive Pinot Grigio
87
Options for clarification of white grape must
Sedimentation
- Must chilled to 4C (avoid oxidation, microbes)
- Faster in large tall vessels (greater depth)
- Racked to fermentation vessel
- Cheapest method
- Time and labour (small volume premium wines)
Flotation
- Inert gas bubbled through must, particles skimmed from top.
- Fining agent must be used to bind particles
- More expensive - equipment
- Batch process - quick
Centrifugation
- Quick
- Continuous (not batch)
- Expensive - large wineries
- Oxidation - optional flush with inert gas
- Wine and must
Clarifying Agents
- Pectolytic enzymes break down pectins
- Cost of agents, no chilling and faster.
88
White wine fermentation - vessels and temps
Temperatures:
- Fruity 15C
- Less fruity 17-25C (oaked chard)
- Yeast health
- Avoid isoamyl acetate
Stainless Steel Tanks
- inert
- control temperatures
- Sauvignon Blanc / Veneto Pinot Grigio
Concrete / Old oak
- slightly warmer temperatures, less fruit
- Chablis, white Rioja
Small oak
- Deeper colour, fuller body
- More integrated oak aromas
- Texture from wine + yeast lees
- Blending options
- Premium + superpremium Chardonnay
89
When is Malolactic Conversion used in white winemaking
Low aromatic wines when greater complexity is required.
Not used for aromatic varieties to keep character of wine (Rielsing, Sauv Blanc)
90
When is barrel maturation used in White Wines
Premium and super premium low aromatic wines (Chardonnay)
91
What are the main options/approaches for producing wines with residual sugar
Concentrating the grape must
- Drying Grapes on the vine
- Drying grapes off the vine
- Noble rot
- Freezing grapes on the vine
In the winery
- Stopping fermentation
- Sweetening
92
What makes wines with natural residual sugar so expensive and high quality
Expense:
- High labour
- Less juice obtained from grape
- Sugary pulp hard to extract during pressing
Quality:
- Sugar is concentrated
- Acidity and flavours are concentrated
- Wine is kept in balance
93
Explain two techniques for drying grapes on the vine, and their resultant effects in the wine
Late harvest wine (Vendages Tardives, Spatlese)
Not botrytised
Extra ripening
- Grape starts to shrivel
- Very ripe flavours
- Pinot gris = stone fruit to tropical as extra ripe
- Long dry autumns to prevent grey rot
Breaking cane
- Cane is cut or broken before harvest
- Grapes shrivel more quickly
- Shorter hang time reduces risk of grey rot
- High level of sugar, no over ripe flavours
94
Explain the technique of drying grapes off the vine, and their resultant effects in the wine
AKA Passito
- grapes picked then dried
- takes days to months
- laid out in sun (hot climates) or temp/humidity controlled room (cooler climates)
- low humidity avoids development of grey rot
- Recioto di Valpolicella, Vin Santo
95
Why are botrytised sweet wines high quality and expensive
- Noble rot not uniform in the vineyard (several pickings required)
- Juice obtained is lower
- Noble rot conditions might not occur every year (damp = development too rapid = grey rot)
- Laccase enzyme oxidative and resistant to SO2 (req. more or chilling down)
- Difficult to press, clarify and ferment (high sugar difficult to ferment)
96
How are botrytised sweet wines matured
- Neutral varieties (Semillon) = oak
| - Aromatic = stainless steel or concrete (retain varietal aromas)
97
What temperature must Canadian Icewine grapes be harvested at
-8C
98
What varieties are popular for Icewine/Eiswein
Resilient skins
- Vidal
- Riesling
- Cabernet Franc
99
How is Icewine/Eiswein fermented/matured
Stainless steel although oak is sometimes used for extra flavours.
100
Dangers to Icewine production in the vineyard
- Grapes eaten by pests before winter freeze sets in.
| - Bird netting often used
101
Advantages and disadvantages of producing sweet wine by stopping the fermentation and how is this done.
How
- Chill wine below 10C
- High dose of SO2
- Racked off sediment
- Sterile filtered
Advantages
- Control over alcohol content (lower - White Zinfandel)
- Wines tend to be off dry / medium sweet
- Simple and low risk
Disadvantages
- Less intensity and complexity, lower quality
102
Advantages and disadvantages of producing sweet wine by adding a sweetening component and how is this done.
```
Addition of sweetening component:
Sugar - not permitted in EU
RCGM - no flavours, just sugar
Unfermented grape juice (sussreserve)
- grape like character
- PDO - must come from same region as wine
```
Advantages
- winemaker can trial and blend different quantities of sweetener
- wine can be stored dry until required (less risk microbial spoilage)
- maintain or increase wine volume
Disadvantages
- acceptable to good quality
- high volume inexpensive wines
- less complexity
103
What is the main focus of extraction in red winemaking and what are the factors that affect this
```
Extraction of:
- Anthocyanins
- Tannins
- Flavours
From grape skins.
```
Factors:
- Temperature (higher = more extraction)
- Time on skins (longer=more extraction)
- Medium (tannins = alcohol (wine), anthocyanins = aqueous (must))
104
How are anthocyanins affected by the red winemaking process
- Source of colour in young red wines
- Not very stable
- Lost in lees ageing or SO2 addition
- Combine with tannins in the presence of oxygen to become more stable
- Anthocyanins and anthocyanin-tannin compounds change in composition causing wine to become paler and ruby -> brown colour.
- Anthocyanintannin compounds more stable than just anthocyanins.
105
Name and describe the three techniques for before fermentation maceration in red wine making.
Cold soaking (pre fermentation maceration)
- Juice and skins chilled to 4-10C
- 3-7 days
- includes punching down + pumping over (reduce microbe growth on cap)
- slow and controlled extraction
- anthocyanins without high tannins (Pinot Noir for colour)
- energy and time = premium wines
```
Heat maceration
Flash detente
- destemmed
- 85-90C
- rapidly cooled under vacuum
- two minutes (limits 'cooked' flavours)
- bursts grape skin cells (anthocyanins and flavours)
- expensive equipment, high volume
- help treat smoke taint
```
Thermovinification
- 50-60C
- several mins to hours (higher temp = shorter)
Heat maceration
- less stable anthocyanins (less tannins to bind)
- intensify fruitiness, reduction in varietal chars
- used for blending
- denature laccase produced by grey rot
- less tannin
106
What does mixing the cap in red wine fermentation achieve
- Better extraction (otherwise liquid around grapes would become saturated)
- Stops top of cap drying out (would not contribute to extraction)
- Distribute heat produced during fermentation
107
What broad choices does the winemaker have in cap management
- Techniques
- Frequency
- Duration
- Timing within fermentation (more colour less tannin at start, more tannin at end)
- Temperature - cooling at end of fermentation = less tannin (when vessel allows it)
108
What is punching down and when is it used
- Submerging the cap in liquid
- Hand or mechanised plunger
- Labour intensive
- Low volume + premium wines
- Gentle
109
What is pumping over and when is it used
- 1/3 to 1/2 liquid is taken from near the bottom and sprayed over cap.
- doesn't break up cap, very gentle (usually used with punching down and rack and return)
- aerobic - yeast health and avoidance of reduction flavours
- can also be done anaerobically
- used on all red wines, all price points
- hoses installed on tank and pre programmed, reduces labour need.
110
What is rack and return and when is it used
- pumping over but into another vessel
- as liquid pumped out, cap falls
- then sprayed back over
- breaks up cap and mixes juice and skins
- much more extractive
- red wines where med-high flavour, colour tannin desired (Cab Sav, Syrah)
- not fully automated - labour
- clean vessel required
111
What are Ganimede tanks and when are they used
- bubble CO2 through must/wine
- pressure builds - cap bursts
- red wines where med-high flavour, colour tannin desired (Cab Sav, Syrah)
- fully automated, less expensive that R&R
- tanks expensive
- can be used with Oxygen as well as inert gas
112
What are rotary fermenters and when are they used
- horizontal closed s/s tanks
- rotate and internal blades break up and mix cap
- horizontal orient. increases surface area
- red wines where med-high flavour, colour tannin desired (Cab Sav, Syrah)
- programmable + automated (labour)
- high volume, inexpensive, mid priced, with acceptable to good quality
- very extractive
- expensive, large volumes
113
What is must concentration and when is it used during red wine fermentation
- Juice drawn off just before crushing (light in colour flavour and tannin and used for rose)
- Concentrates remaining juice, lower volume.
- Saignee
114
What is co-fermentation and when is it used during red wine fermentation
Fermenting different grape varieties in the same vessel. Normally small proportion of white grapes within red wine fermentation (Cote Rotie - Shiraz/Viognier)
White grapes contrbute:
- Phenolic compounds (bind with anthocyanins - increase colour intensity and stability)
- Aroma compounds (terpenes in Viognier)
Too much:
- Dilution
- Lower colour intensity.
115
What effect does adding stems to fermentations and when are they used in red wine making
- Add 'spicy' or 'herbal' flavours.
- Unripe stems add green flavours and bitter tannins
- Not common when fermenting grapes high in tannin - Cabernet Sauvignon
116
Explain the objective of whole berry / bunch fermentations in red wine
- Create oxygen free environment
- Grapes aerobic respiration to anaerobic -metabolism
- Intracellular fermentation - sugar is converted to alcohol (no yeast)
- Malic acid -> ethanol
- Reduces Malic acid levels by <50%
- Lowers acidity, raises PH
- Increases Glycerol (texture)
- Aromas created
- No significant impact on cost
117
Explain differences between Carbonic and Semi Carbonic maceration
Carbonic
- whole uncrushed bunches in CO2 filled vessel
- Once alcohol = 2%, grapes are presssed (tannins extracted in alcohol so less alcohol extracteD)
- Wines best consumed a year after harvest
- Improve grapes grown at high yields or not fully ripe.
- acceptable, good, inexpensive mid priced (Beaujolais)
Semi Carbonic
- Vessel not filled with CO2
- Grapes at the bottom are crushed under weight and release juice
- Ambient yeasts ferment
- Fermentation produces CO2, fills vessel, remaining grapes Carbonic Maceration
- Grapes split, release juice, are presssed
- Winemaker may increase concentration, body and tannin by continuing alcholic fermetnation on skins.
- Decreasing Carb. Mac. takes places untill all skins are broken up.
- Followed by postfermentation and oak maceration to increase complexity
- More fruitness and softer mouthfeel than crushe fruit fermentaiton
- Fruity Pinot Noir, Malbec, Tempranillo, Gamay, Carignan
Whole Berries with Crushed Fruit
- Mix crushed grapes with whole berries/bunches
- Submerged by crushed grapes and kept from oxygen
- More 'carbonic' = more whole berries
- Progressively crushed
- Similar to semi carbonic
118
Explain red wine fermentation temperatures
- Fruity, low tannin - 20C
| - Greater extraction (complexity, aging) - 30C
119
Explain red wine fermentation vessels
Stainless steel, concrete, oak (large vat)
- Open at the top (extraction techniques) or closed
- fruit flavours
Small oak (225-500l)
- Kept on side with heads removed to form small open top fermenter
- Rounder mouthfeel better integration of oak
- Labour intesive
- Premium + Super premium
120
What is post fermentation maceration and why is it carried out
What? Red wine grapes kept on skins for a few days to weeks after fermentation.
Why? Improving tannin structure = aging potental
- Premium, super premium, very good, outstanding wine intended for aging.
- Tank space and time
121
Differences between pressing for red and white wine
- Black grapes more protected against oxidation so flushing with inert gases less used.
- Free run wine drained, grape skins removed and pressed.
- Press wine may be mixed as blending component (colour, flavour, tannins) or sold for distillation.
- Press timing variable (2% alc for Carbonic --> after post fermentation maceration)
- Can press just before alcoholic fermentation to dryness, to allow ferment to finish in barrels (oak integration, rounder mouthfeel)
122
When can malolactic conversion occur for red wines
- in oak barrels - better integration of oak characteristics
- during alcoholic fermentation
- after alcoholic fermentation
123
When will a winemaker mature red wine in oak and what are the effects
Inexpensive
- released soon after fermentation
- oak flavours from staves or chips
Mid market / Premium / Super premium
- at least a few months in oak
- higher prop new oak if vanilla/clove flavours would enhance wine
- less new oak, subtle flavours more fashionable
- gentle oxidation softens tannins and helps development of tertiary aromas/flavours
Unoaked Mid market / Premium / Superpremium
- Focus on primary aromas and flavours
- Loire valley Cab Franc, Spanish Mencia, Argentine Malbec
124
How is lees aging for red wines carried out and what are it's effects
- Soften tannins
- but reduce colour intensity
- racking controls amount of less present
- no gross lees, no stirring
125
Direct pressing for making rose wines
- Lightest coloured roses
- Black grapes are whole bunch pressed or destemmed and immediately pressed
- Penumatic presses with inert gas (longer press = more maceration)
- Fermented like white
- Vin Gris (light Provence wines)
- co-pressed / co-fermented with black grapes for paler colour and extra acidity (Vermentino allowed in Provence)
126
Short maceration for making rose wines
- Short pre fermentation maceration (hours to a few days)
- Spanish style, Tavel roses
- Can be by product of must concentration (saignee = bleeding) (disadvantage of grapes being grown for red wine not rose but good wine can be made)
127
Blending for making rose wines
- Blending red with white wine
- Not allowed in Europe (apart from Champagne) as thought it would lower quality.
- Inexpensive wines
- Easily create wine of desired colour
128
Colour in rose wines
- Consumer associates lighter = drier
- Colour lightens during fermentation
- Skill and experience required to predict final colour
129
General characteristics of rose wine (acidity, alcohol, flavours)
- Medium high acidity
- Low-medium alcohol
- Fresh fruit flavours
130
Where do grapes for rose tend to be grown
- Cool-moderate regions (or sites within warmer regions)
| - Cooling latitude, aspect, proximity to large water bodies, coast.
131
Viticulture considerations for black grapes grown for rose
- Grapes are grown with higher yields in mind than for red wine (slow ripening, less concentration)
- Minimal tannins (black grapes with low/med colour and tannins used)
- Tannins must be ripe to avoid green flavours
- Hand harvesting = whole bunch pressing = low colour juice
- Machine harvesting = at night, large volumes at specific ripeness level
132
How are rose wines fermented
General:
- 12-16C
- s/s tanks
- Cultured yeasts that promote fruit flavours
- Malo avoided (flavours unappealing, retain acidty)
- Fined and filtered (visually appealing),
- Sterile filtration for wines with r/s
More premium:
- Short lees/oak maturation option, mid priced crated for food pairing
- Oak (new + old) occasionally for texture (expensive)
