WSET Diploma D1 General Wine Making Options CH13 Flashcards
What are 2 most fundamental Gases in Winemaking and Maturation
Oxygen & Sulfur Dioxide
How can oxygen on the must or wine be limited
- Avoid ullage in vessels - topping (wood vessels gradual loss through evaporation
- Use of Inert Gases to flush out oxygen (nitrogen, carbon dioxide, argon)
- Addition of SO2 (anti oxidative effects)
- Use of impermeable containers (Stainless Steel, Glass & Screwcap, Thick concrete)
- Cool consistent temps (in cellar, while picking, slows oxidation)
How is or can oxygen be positive for wine/must
- Required to start fermentation
- Needed for health yeasts
- Oxidation stability (before fermentation, longer aging)
- Essential for anthocyanin and tannin reactions, COlor stability
- Quality/style of wine
- Develop aromas and flavor characteristics
Ways to increase oxygen exposure
- Cap management techniques (red wine)
- Small wooden barrels with small amount of wine
- Increas number of rackings or lees stirring
- Allow ullage in conatiners without inert gasses
- Pump oxygen through must
What is SO2 primarily used for, and what are its 2 main properties
What forms can it come in
Preservative in wine
- Anti Oxidant - reacts slowly with oxygen, reduces oxidation effects
- Anti Microbial - slows development of microbes (yeast, bacteria)
Gas, Liquid, Solid
What is Max SO2 you can use in EU
210 mg/L - Red Wines
160 mg/L - White Wines
How uch SO2 naturally occurs, at what point must contain sulfites be put on the lable
up to 10 mg/L, anything more must be put on the lable
Bound SO2 vs free SO2
Bound - when SO2 added to must or wine, dissolves and some reacts with compounds in liquid, ineffective against oxidation and microbes
- Free, portion non bound, relatively inactive. Some is Molecular - effective agains oxidation and microbes
pH vs SO2, explain the relationship
In winemaking, when is most effective time to add SO2
More free SO2 in molecular form in lower pH levels
More SO2 needs to be added to wines with higher pH levels
Larger amounts when grapes are crushed, after mololactic conversion, and at bottling
What negative effects can SO2 have on wine
What can winemakers do to lower amount of SO2 needed
Full aromas/flavors
Cause wine to taste harsh
- Good winery higiene, good grape sorting - limits
harmful microbial activity - Limiting oxygen exposure
- Keeping grapes, must or wine at cooler temps
When transporting grapes after harvest what are grapes vulnerable to
How to limit and minimixze these threats
Oxidation, ambient yeasts, acetic acid baterial (alcohol to vinegar)
Ways to minimize
- Night harvest, or sunrise to keep cool temps
- SO2 addition
- Cold storage room once recieved at winery
- Sanitizing harvest equipment/bins
- Small crates, minimize crushing
When grapes are recieved at the Winery what are ways to move them around
what are the steps to reception and the goals of these steps
conveyor belt, fork lift, pallet truck
- Chilling (reduce oxidation, spoilage: use heat exchangers, or refrgeration units. Night harvest)
- Sorting (for desired wine quality and price based on number of factors)
- Destemming (usually upon arrival at winery, stems contain tannin, underipe stems create bitterness green notes in wine)
- Crushing
What is the goal of chilling
What methods of chilling grapes are used in reception
Disadvantage
- reduce oxidation, spoilage
- use heat exchangers, or refrgeration units.
- Costly in machinery and energy, Night harvest in warm climates can help
What factors are taken into consideration in sorting
Disadvantages
Remove MOG (Material other than grapes), underipe/damaged fruit
- RIpeness of fruit
- How healthy the fruit is
- What the desired quality of and price of wine is
- If any sorting occured in the vineyard
- Physical state of grapes
- Costly in time, labor, and yield (more particular tends to be less fruit)
What sorting options for inexpensive or quality wines are there
- So may not require any sorting for inexpensive
- Removing unwanted grapes or bunches while picking
- Hand Sorting - tables, conveyor belt, vibrating belt (before or after desteming, sometimes both)
- Optical sorting - expensive, 100 grape samples, premium and super premium wines
What are some examples of grapes or styles that would not be destemmed
- Red wines that use whole bunches (ex Pinot in Burgundy)
- Carbonic Maceration (gamay in beaujolais)
- Whole bunch pressing for some white wines (common in sparkling)
Explain Crushing
How it is done now and was traditionally done
Explain “Must”
Beginning of winemaking process, applying enough pressure to break the skins of grapes and release juice
Trasitionally human feet, now machine, usually attached to destemmer, or if whole cluster during punch down
Must is mixture of juice, pulp, skins, and seeds that come out of crusher
When does pressing usually occur in White vs Red Winemaking
Goal of pressing white vs red
White Winemaking - before fermentation, usually after destemming
Maximize juice without extracting tannin or seeds
Red Winemaking - Pressed after desired number of days on skins or after fermentation
Patriculrly soft, not to extract extra bitter tanning from soft grape must that has been soaking
Both need soft pressing
What different types of presses are there, explain each
Advantages & Disadvantages
Pneumatic Press - ‘Air bag or Bladder press’ - Most common, Cylindrical cage with blandder running down middle or side, bladder fills with air pushing crapes into grates. batch processing
Adv.
Programmed for amount of pressure
Can be flushed with inert gas to protect juice from oixidation
Dis.
High initial investment
Basket Press “Vertical Presses” or “Champagne Presses” - more traditional form, but still used by some
Basket filled with grapes and pressure applied from above, juice runs through gaps or holes in sides, huice collected in tray at bottom, batch processing
Adv
Some winemakers believe to be more gentle
Dis
Smaller loads, more labor intensice
Not sealed, no inert gas to avoid oxygen exposure
Horizontal screw Press - similar to basket, rectangle draining tray, less gentle, batch processing
Continuous Press - screwing mechanism, quicker pressing for large volumes
What are Must Adjustments and the goal of Must Adjustments
Are the cateories of corrections to Must that can be taken
Creat more balanced wine, especially if there have been compromizes to the grapes
- Enrichment, Sugar of Chapitalization or Adding Alcohol
- Reducing Alcohol
- Acidification
- Deacidification
The Steps of General Winemaking Options after harvesting and before Maturation
- Oxidation & SO2
- Transportation to Winery
- Grape Reception
- Pressing
- Must Adjustments
- Fermentation
- Malolactic Conversion
- Post Fermentation Adjustments
Explain Enrichment
What can be used
When is Sugar Added
Other Ways of Enrichment
Enrichment is when sugar is added, usually in cooler regions where the grapes do not ripen as much to increase alsohol of final wine
Dry Sugar - also Chaptitalization, beet or cane sugar
Grape Must
Grape Concentrate
RCGM - Rectified Concentrated Grape Must -manufatured flavorless syrup
Usually added suring fermentation because yeast is active and can cope better with additions
Sugar can be concentrated in must by removing water, reverse osmosis, vaccum evaporation, or cryo extraction (all are more expensive although cryo the least, either for equipment costs or reduced yields)
Explain Reducing Alcohol at this step
Advantage and Disadvatage
Lower potential alcohol, can be done by adding water, perhaps warmer climate where sugar concentration is increased in grapes
Only leagal in some counties
Dilutes grapes aromas and flavors
Other ways would be post fermentation
Explain why you mould need acidification
Which acid(s) are used
When would acidification occur
In warm climate without cooling influences, Malic acid would drop rapidly as grapes ripen, wine could lach freshness
Used to lower pH
For inexpensive - mid priced - premiums wines in warm climates
Typically addition of tartaric acid Other grape acids: - Citric - Malic - Lactic
Before, During or After Fermentation but winemakers believe better integration before and starting with lower pH
In EU not allowed to hapitalize and Acidify
Explain why you would need deacidification
How is deacidification done
when would deacidification occur
In cool climates where grapes are picked before fully ripe
Adding calcium carbonate (chalk) or potassium carbonate forms tartrates lowering acid
Hightech option is ion exchange - cosiderably expensive, must be legal
Take Malolactic conversion into play for acid
Explain why you would need to add tannin
How can tannin be added
when would Tannin addition occur
To clarify must, stablize color, improve mouthfeel
Powdered tannin
Before fermentation or before maturation
What decisions should be made or what is required for Alcoholic fermentation
1) Yeast
a) Ambient Yeast
b) Cultured Yeast
2) Temperature
a) Cool 12 - 16C (54-61F) Fresh fruity whites and rose
b) Mid 17-25C (63-77F) Easy fruit reds, low tannin, less fuirty whites (barrel fermented whites)
c) Warm 26-32C (79-90F) Red wines high concentration pronounced tannin, loose some fruit aromas
3) Fermentation vessels
a) Stainless steel
b) Concrete
c) Wood
Define Alcoholic Fermentation
Conversion of Sugar into Alcohol (ethanol) and Carbon Dioxide carried out by yeast in absence of oxygen
Produces heat which has to be managed
Define Yeast
collective term given to group of fungi that convert sugar into alcohol and effect flavor/aroma characteristic. Need oxygen to multiply quickly, then convert to alcohol when oxygen is gone
What conditions do yeast need to produce alcohol
What is most common Yeast
- Viable temp range
- Access to yeast nutrients
- Nitrogen
- Absence of Oxygen
Saccharomyces Cerevisiae
Aside from Alcohol, CO2 and heat what does Alcoholic Fermentation produce?
- Volatile Acidity (VInegar, nail polish)
- Wine Aromatics (Thiols, Terpenes)
- Aromatics created by yeast (banana)
- Undesireable sulphur reductive aromatics (rotten eggs, rotten cabbage)
- Acetaldehyde (bruised apple, paint thinner)
- Glycerol, increases body of wine
Where is ambient yeast (wild yeast) found
Advantages and Disadvantages to using
- Present in vineyards and winery- includes range of species - tends to die after 5% alcohol
Adv
- Adds complecity from multiple yeast species producing different aroma compounds
- Costs nothing to use
- Can be unique to a place or region
- Can be used to market wine
Dis
- Fermentation may start slowly (build up of VA, Spoilage Aromas leading to off flavors)
- Fermenting to dry may take longer, risk of stuck fermentation
- Consistent product not guaranteed
Where is cultured yeast (selected or commercial yeast) from
What do you need to use it
Advantages and Disadvantages to using
Selected in labs, grown for volumes suitable for sale
Selected strains of singel Saccharomyces Cerevisiae
To use
Cool must so ambient yeast is not fermenting
or
Add SO2 to surpress ambient yeast
then
Starter batch of fermenting cultured yest, and the rest of cultured yeast
Adv
- Reliable fast fermentation to dryness
- Due to speed less VA, spoilage organisms and bacteria, security of clean complete ferment
- Consistent product vintage to vintage
- Can shoose for style with such large selections to pick from
Dis
- Some believe cultured yeast leads to certain similarity of fruit expression “Industrial Wine”
- Adds cost of using commercial product
Explain what temperatures you need for Fermentation
What is temp slows or stops fermentation
How can temp be controlled
a) Cool 12 - 16C (54-61F) Fresh fruity whites and rose
b) Mid 17-25C (63-77F) Easy fruit reds, low tannin, less fuirty whites (barrel fermented whites)
c) Warm 26-32C (79-90F) Red wines high concentration pronounced tannin, loose some fruit aromas
Above 35C (95F) is where yeast struggles to survive
Options of controlling temp
- Fermentation rooms - warmer or cooler
- Fermentation vessel may have temp control installed
- Water or Glycol jackets (or inserts) that surround the vessled (or inserted)
Pumping over releases heat
What are different types of Fermentation Vessels
- Stainless
- Concrete
- Wood
Other
- Plastic Vessels
- Terracotta (amphorae)
- Qveri (georgia)
- Tinaja (Spain)
What are Advantages and Disadvantages to stainless steel as fermentation vessels
Adv.
- Most common
- Easy to clean
- Many sizes enables temp control
- Neutral Vessel, protects wine from oxygen, dont add flavors
- High level of Mechanization possible
Dis
- Costly initial investments of tanks and computer temp control systems
What are Advantages and Disadvantages to Concrete as fermentation vessels
Adv
- Were inexpensive last century
- High thermal inertia, maintain even temp
- New eggs permit natural lees stirring
Dis
- Eggs are very costly
What are Advantages and Disadvantages to Wood as fermentation vessels
Adv
- Retains heat well
- Allow small amount of oxygen (can be good, expecially in red wine)
- Can be reused many times (inexpensive long term)
- White wines can be fermented in them
Dis
- Red wines difficult to ferment to to need of cap management
- Harbours bacteria and spoilage organisms, hard to clean
What is Malolactic Conversion
How did it used to happen vs How
What conditions encourge and prevent it
Lactic Acid Bacteria converts MAlic Acid into Lactic acid and CO2. Typically after fermentation
Historically occured in spring when barrels warmed in cellar, now Cultured lactic acid bacteria is added
Encourages
18-22C (64-72F)
Moderate pH - 3.3- 3.5
Low SO2
Discourages
Temp below 15C (59F)
low pH
moderate SO2
- can add enzyme lusozyme which kills lactic acid bacteria
- Can filter out lactic acid bacterial
- Move wine to another part of winery avoiding spread of lactic and bacteria
What are the outcomes of Malolactic Conversion
- Reduction in acidity, rise in pH, if already low in acid then smoother, softer wine
- Some color loss in reds
- Greater microbial stability, having it go through malo prevents from spontaneously going through malo later
- Modification in flavor - increase VA, slight loss of fruit character, adds buttery conponent
What are Post Fermentation adjustments winemakers can do before maturing, packaging and finishing the wine
Why would you do these steps
Goal is to only make necessary small adjustments post fermentation to not upset balance
- Removal of Alcohol (for reduced alcohol wine) or to adjust alcohol level marginally
a) Reverse Osmosis
b) Add Water
c) Spinning Cone - Correcting Color (if permitted)
When Removing Alcohol in Post fermentation adjustments what are 3 ways to do this
Advantages and disadvantages
1) Adding Water Adv. Simple, inexpensive, adds quantity DIs. Reduces intensity of flavor
2) Reverse Osmosis - type of crossflow filtrationthat removes flavourless permeate pf alcohol and water, which can be distilled to remove alcohol, then blended back.
Adv
Common, thurough, doesnt change flavor/aromas as much
Dis
Equipment costly even in rented
3) Spinning Cone - device that first extracts volatile aromas from wine, then removes alcohol. Aromas compounds blended back into wine Adv Used for large volume production Dis Specified laws Lower quality generally
What are ways to change color during post fermentation adjustments
1) Reduce unwanted color tints
- Fining the wine
2) Enhance color intensity (high volume)
- Adding small amounts of grape derived coloring agents (ex MegaPurple)
