Ch 17 RS Winemaking Options Flashcards

1
Q

RS Winemaking Options

In general, what are the 3 main ways of making wines w/RS?

A
  1. Concentrate sugar in grape must - drying grapes on or off vine
  2. Stop Fermentation (chilling)
  3. Blend in sweetener
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2
Q

RS Winemaking Options

What are the three main ways sugars are concentrated in grape must?

A

Dry grapes on or off vine
Noble rot
Freezing on vine

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3
Q

RS Winemaking Options

What are the 3 main factors winemakers need to consider?

A
  1. Desired QSP
  2. Climate of vineyard site
  3. Local laws
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4
Q

RS Winemaking Options

What is the objective for winemakers making wines w/ RS?

A

Make a wine with balanced RS and acidity and flavor concentration appropriate for sweetness level

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5
Q

RS Winemaking Options

What styles are made by concentrating sugar in grape must?

A

Sweet and luscious

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6
Q

RS Winemaking Options

What are 2 general ways sugar is concentrated in grape must?
Why and what are considerations?

A
  1. Fermentation stops naturally -> yeast struggle in very sugary environ esp when alc also present -> naturally stop ferm even at low alc levels
  2. winemaker stops ferm -> chilling or adding SO2, then filtering out yeast = winemaker has more control over balance of alc and sweetness
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7
Q

RS Winemaking Options

Overall, how does concentration of grape must work and what happens in the process?
What quality levels use this?

A

○ Must is concentrated by reduction of water in the grape -> concentrates not only sugar but also other components like acid and flavors
○ Increased acidity keeps sweetness in balance -> why many of these wines are very good or outstanding quality
○ Method of removing water from grape can also add its own flavors -> ex dry on vine adds dried fruit = more complexity that wines made by simply stopping ferm, chilling or adding sweetener

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8
Q

RS Winemaking Options

What are implications/considerations for winemaking of concentrating must?

A

○ Removing water from grapes means volume of juice is low
○ Sugary pulp can be hard to extract during pressing
○ Inc costs -> often premium or super prem

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9
Q

RS Winemaking Options

What are 4 ways of concentrating grape must?

A
  1. Drying on the vine
  2. Drying off the vine
  3. Noble Rot
  4. Freezing on the vine
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10
Q

RS Winemaking Options

How are grapes dried on the vine?
What happens to the grape and what environ condition is needed for this to happen?
Examples?
Labeling implications?

A

○ If grapes left on vine, they enter stage 4 of ripening process
○ Water is lost via grape transpiration -> concentrates sugars and flavors can continue to develop
○ Ex - PG may develop from stone fruit to tropical fruit and dry stone fruit
○ Dry autumn needed to avoid grey rot -> would give off flavors
○ Can be labelled as late harvest incl Vendages Tardives from Alsace and Spätlase from Germany/Austria

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11
Q

RS Winemaking Options

What is another method of drying grapes on the vine?
How is it done?
Why do it and what are considerations?
Example?

A

○ Cane of vine is cut a short time before harvest - usually stays on trellis
○ Grapes shrivel more quickly since not attached to vine -> concentrates sugars, acids and flavors
○ Reduced hangtime reduces - but doesn’t elim - grey rot risk
○ Allows getting grapes with very high sugar levels w/o extra ripe flavors - due to speed of concentration
○ Ex - sweet wines in Jurançon (SW France) and sometimes Australia

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12
Q

RS Winemaking Options

What is process for drying grapes off the vine?
What happens?
What conditions needed in warm vs cool climates?
Aka and examples?

A

○ Fully ripe grapes are picked and then dried
○ Drying process causes water to evap -> concentrates sugars, acids and flavors
○ Drying can last days to months - depends on amt of drying needed and speed of drying process
○ Warmer climate -> bunches can be laid out to dry in sun -> S Italy/Spain
○ Cooler climate -> bunches dried in temp and humidity controlled room -> speed up drying and avoid grey rot ex - Valpo
○ Climate controlled rooms more expensive
○ Aka - Appassimento method in Italy - Recioto di Valp and Vin Santo

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13
Q

RS Winemaking Options

What is noble rot and how does it relate to grey rot?
What conditions are needed for it?
what does it do to the grape?
What does it add to wine?

A

○ Botrytis cinerea fungus
○ Same as grey rot, but in proper conditions creates concentrated sugar and flavors in grapes
○ Grapes must be fully ripe before rot dev
○ Must be in region w/ misty/moist mornings and sunny/dry afternoons ->
○ damp mornings allows rot to dev -> punctures grape skin with microscopic filaments - leaving tiny holes in skin
○ Warm afternoon sun slows dev of rot and causes water to evap -> concentrates sugars, acids and flavors
○ Fungus also creates some aroma compounds and generates unique flavors -> honey, apricot, citrus zest, ginger, dried fruit

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14
Q

RS Winemaking Options

What QSP use noble rot?
Examples?

A

○ Prem/super prem sweet wines - sauternes, BA, TBA, Tokaji
○ Much more common on white grapes than black
○ Term botrytised often used on labels

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15
Q

RS Winemaking Options

What are viticultural implications of noble rot?
What happens in bad conditions?

A

○ Spread of noble rot never uniform -> can req several picking by hand to select best grapes
○ Expensive process - skilled labor and time
○ Volume of juice low -> selective picking and water has evap from grapes
○ Ideal conditions may not happen every year -> wines can be scarce/expensive
○ If wrong conditions (too damp) -> fungus grows too fast and grey rot forms -> split grapes and encouraging infections

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16
Q

RS Winemaking Options

What are challenges in winemaking for Bot grapes?
What options to address?
What winemaking options used?

enzyme

A

○ Fungus adds an enzyme - laccase - that can oxidize some components in grape must and wine and is relatively resistant to SO2
○ Chilling and high doses of SO2 and use of inert gases to protect are options to reduce oxi of must
○ Thick, high sugar content grapes can be hard to press, clarify and ferment
○ Often mat in oak (old or new) esp for neutral grapes (eg Semillon) -> gives more texture and new oak can add tannin and some flavors (vanilla)
○ Aromatic var - tend to be stored in s/s or concrete to preserve varietal aromas

17
Q

RS Winemaking Options

How are grapes frozen on the vine?
What happens?
Where is it done?
What are laws?

A

○ Requires healthy grapes to be left on vine into late fall and/or winter
○ Freezing temps -> water in pulp turns to ice
○ When picked and pressed, ice stays in press -> releases concentrated juice
○ Eiswein in Germany/Austria and Icewine in Canada
○ Protected labeling terms -> e.g., Icewine can only be used if grapes harvested at -8°C or below

18
Q

RS Winemaking Options

What are viticulture and winemaking considerations for freezing grapes on vine?

A

Viticulture
○ Vines need to be winter tolerant and grapes w/ resilient skins that can offer disease protection and withstand strain of freeze/thaw cycles
○ Most popular var - Riesling and Vidal, sometimes CF

Winemaking
○ Ferm and stored in s/s to retain primary aromas
○ Oak ferm sometimes done to add extra flavors

19
Q

RS Winemaking Options

What environ conditions needed for freezing grapes?
What considerations/risks?
What price point usually?

A

○ Very specific conditions -> only a few places can do it
○ Freeze/thaw cycle thought to be important to dev of typical icewine char
○ Highest qual but lowest yielding grapes picked late in season - late Jan
○ Juice yield very low
○ Signif risk of disease and pests -> further impact yields -> netting vs birds signif cost
○ Prem/super prem

20
Q

RS Winemaking Options

What is an alternate method for freezing grapes?
When is it done?
Adv/considerations?

A

Cryo-extraction - pick grapes at regular harvest in fall and then freeze at winery
○ Done in areas w/o climatic conditions
○ Adv - no risk of leaving grapes on vine
○ Consider - cannot use Eiswein or Icewine on label,
○ Incur energy cost to freeze grapes -> but cheaper than regular icewine prod

21
Q

RS Winemaking Options

What is the process for stopping fermentation?
How is main way it is done, what is another way and what does that create?
What is a key example and how is it done specifically?
Advantages/considerations?

A

○ Stopping ferm before all sugars converted to alc -> creates wine w/ RS
○ Most common way - chill to <10°C and/or add high dose of SO2 to inhibit yeast
○ Wine then racked off sediment and sterile filtered -> ensure ferm doesn’t start again later
○ Earlier stopped -> higher RS and lower alc. Ex - white zin (no concentration of grapes) = 35g/L RS and 10%abv
§ Tastes off-dry to med sweet
○ Fortification also an option (kills yeast) but radically changes style of wine
○ Adv - winemaker has lots of control over sugar level in final wine; fast and easy -> good for high vol/inexp or mid-price
○ Consider - less complexity, lower quality levels - except fortified that are long aged

22
Q

RS Winemaking Options

What is easiest method for concentrating sugars in must and why?
What benefits?
What QSP?

A

○ Blend in sweetener
○ Dry wine can be stored until ready for bottling and then sweetener blended in
○ Less risk of spoilage orgs than wines w/ RS
○ High degree of control/consistency -> winemaker can trial, measure and add exact amt of sweetener desired = good for high vol wines that need consistency
○ Can maint/slightly inc vol of wine - unlike other methods of concentration -> avoid this cost
○ Usually high vol/inexp - acceptable to good qual

23
Q

RS Winemaking Options

How is blending sweetening component done - 2 ways?
What are the names of the sweeteners?

A

○ RCGM and unfermented grape juice (süssreserve) are most common sweeteners
○ Unfermented grape juice -> adds grape juice quality
○ RCGM - processed to only have grape sugar in neutral solution -> less needed
○ Both are inexpensive
○ Local laws sometimes det what can be used - ex sugar not allowed in EU; PDO wines unferm grape juice must come from same region as wine being made