17. Specific Options for Wines with Residual Sugar

Question 1

What is an alternative method of drying grapes on the vine?

How does the process work, and what will the flavors be like?

What are the benefits of this method (2)?

Where is it commonly used (2)?

Answer 1

• cutting/breaking off cane and leaving on trellis a short time before harvest.
• Grapes will shrivel due to lack of water coming from the main vine structure, concentrates acids, sugar and flavors just like late-harvesting.
• However, flavors will not be extra-ripe, though sugar will be high

BENEFITS: method is quicker / reduced hang time = reduced risk of grey rot.

Common in Jurnançon, SW France / Australia

Question 2

Explain what is happening in the image below:

Answer 2

Shrivelled grapes have been left on the vine to dry.

Question 3

What is the easiest way to produce a wine with RS?

What are the benefits of this (3)?

Answer 3

• blending in a sweet component
• dry wines are less susceptible to microbial spoilage => dry wine can be stored until ready to be bottled then sweetening component blended in.
• winemaker can trial+measure – lots of control over style+flavor
• can increase final volume of wine

Question 4

What are the 2 main ways in which grapes are dried OFF the vine?

Which is more expensive?

Answer 4

1) This can be done outside in the sun (warm/dry climates e.g. S. Italy)
2) or in temp/humidity controlled rooms in cooler/humid climates (e.g. Valpolicella)

Option #2 is $$$ (special building/technology + maintenance required)

Question 5

Why are Botrytized grapes difficult to process in the winery (3)?

Answer 5

• Botrytis produces “laccase”, an enzyme that can oxidize components in must+wine.
• Chilling + high doses of SO2 + inert gases are required to minimize its effects.
• Thick, high sugar must = difficult to press, clarify + ferment.

Question 6

How does drying grapes on the vine lead to concentrations of sugar?

What is required for this to happen successfully?

What are some terms for this process (3)?

Answer 6

• Grapes enter stage 4 of ripening, begin to shrivel and water is lost via transpiration.
• Long, dry autumns are necessary to avoid grey rot.

“Late Harvest” / “Vendanges Tardives” (Alsace) / Spätlese (Germany)

Question 7

What type of wine is typically produced by sweetening with an additonal componenent (as opposed to sugars being concentrated) (2)?

Answer 7

• typically high volume, inexpensive wines.
• due to this, quality is typically acceptable / good.

Question 8

What is cryoextraction?

What effect does it produce?

Where is this method used?

What are benefits to this method of concentrating sugars (3)?

Answer 8

Picking grapes in autumn and freezing them at the winery

–> similar effect to ice wine (but cheaper), however the term “ice wine” can’t put it on the label.

• practiced in regions that lack typical conditions required for Icewine
• no risk of leaving grapes on vine for disease/pests; no need for perfect weather conditions; much cheaper overall.

Question 9

What are the 2 main ways wine made with Botrytized grapes is aged?

What are benefits of each?

Answer 9

New/Used oak: can enhance flavors of neutral varieties, e.g. Semillon, with vanilla notes / can broaden texture w/tannins.

Stainless steel: better for aromatic varieties, e.g. Riesling, to retain their pronounced varietal purity.

Question 10

What is an example of a regulation that must be followed when producing Icewine?

Answer 10

In Canada, grapes for Icewine must be harvest at -8 C (18 F) or below.

Question 11

Explain what is happening in the picture below:

Answer 11

Corvina grapes are drying in racks for Recioto della Valpolicella.

Question 12

Both Moscato d’Asti and White Zinfandel can be sweetened how?

What are the differences between them?

Answer 12

They both can be sweetened by stopping their fermentation before all sugars have been fermented into alcohol.

Md’A = Fully sweet, 120-130g/l of sugar, 4.5-6% abv.

White Zin = Off-dry - med. sweet, ~8.5% abv

Question 13

What are 4 factors that determine the method a winemaker will use to make a wine with RS?

What is the ultimate goal of the winemaker?

Answer 13

1. Specific style (i.e. regional like Sherry)
2. Quality and Price.
3. Climatic conditions in the vineyard.
4. Local wine laws.

Ultimate goal is to produce a wine that has balanced levels of sugar, acidity, and flavor concentration.

Question 14

Why is Icewine so difficult / costly to produce (3)?

Answer 14

• Can only be produced in a few regions when weather conditions are perfect.
• unpicked grapes are at risk of disease / pests / birds; netting or extra preventative measure = $$$
• highest quality grapes are also the lowest yielding, and volume of juice is low.

Question 15

What factors cause wines made with Botrytized grapes to be so expensive (3)?

Answer 15

• Rarity; only produced when conditions are ideal (if too damp, grey rot will develop; if not damp enough, botrytis will not develop)
• Time + Labor; spread of botrytis is never uniform and several passes in the vineyard are required. Skilled labor is required for this.
• Volume; even when conditions are perfect, the volume of juice is low due to evaporation of water.

Question 16

Why might the concentration of sugars in grape must be enough to stop fermentation (2)?

Answer 16

• yeasts struggle in very sugary environments, especially when alcohol is present.
• fermentation may stop naturally even at relatively low levels of alcohol.

Question 17

What are the advantages of creating sweet wine by manually stopping fermentation before sugars have all be converted to alcohol (2)?

What is a drawback?

What are some common examples of wines made this way?

Answer 17

• winemaker has more control over level of sugar in final wine (earlier stopped = more sugar, less alcohol)
• relatively quick, simple, low risk and cheap.

wines are usually simple, lacking in complexity/quality compared to sweet wines made by other methods.

Moscato d’Asti / White Zinfandel

Question 18

How might local wine regulations influence how wines are sweetened (2)?

Answer 18

e.g. EU does not allow use of sugar.

For PDO wines, unfermented grape juice used to sweeten wine must be from the same region as the final wine being made.

Question 19

How does freezing grapes on the vine concentrate sugars (3)?

Where is this technique most widely used (3)?

Answer 19

• healthy grapes are left on vines into winter months.
• when frozen, water mols in pulp turn to ice.
• grapes are picked+pressed, leaving the ice behind, which concentrates sugar/acid/flavors of resulting juice.

Common for Eiswein in Germany + Austria / Icewine in Canada.

Question 20

What are 3 things that can be blended into a wine to make it have higher RS?

Answer 20

1) sugar
2) RCGM – more neutral because it is just grape sugar; less is required
3) unfermented grape juice (sussreserve) – gives grape-juice-like character

Question 21

What are some famous examples of wines made with Botrytized grapes (4)?

Answer 21

Sauternes / Beerenauslese / Trockenbeerenauslese / Tokaji

Question 22

What types of grapes are well-suited for Icewine production?

3 examples?

How are they usually fermented/aged in the winery?

Answer 22

• best to use winter-hardy varieties w/resilient skins that offer protection from disease + freeze-thaw cycles.
• e.g. Riesling / Vidal / Cabernet Franc.

Mostly vinified in stainless steel to preserve aromas/flavors of grapes, though oak is occasionally used to add flavors (vanilla, clove)

Question 23

How does Botrytis cinerea affect grapes (2)?

What unique aromas does it impart (5)?

Answer 23

The fungus punctures grape skins w/tiny filaments = microscopic holes through which water evaporates.

-This causes concentration of sugars/acids/flavors.

Some aromas+flavors: honey / apricot / citrus zest / ginger / dried fruit

Question 24

Describe the 2 opposite ends of the spectrum when it comes to wine made with RS:

Answer 24

On one end, you have inexpensive wines that contain low-med. amounts of RS to make them more appealing to a larger consumer audience.

On the other, you have preium-super-premium wines w/RS levels of a few hundred g/l and syrupy texture.

Question 25

What are conditions required for Noble Rot (3)?

Answer 25

• grapes must be fully ripe before development of rot
• grapes must be grown in a region that has humid, misty mornings (allows rot to develop on grapes)
• and sunny, dry afternoons (slows development of rot, allows water to evaporate)

Question 26

What are four ways to naturally concentrate grape must?

Answer 26

1) drying grapes on vine (e.g. Vendange Tardive)
2) drying grapes off the vine (e.g. “passito”)
3) noble rot (e.g. Sauternes)
4) freezing the grapes (e.g. Eiswein)

Question 27

Why do wines w/RS made by concentration of sugar in the must tend to be of very good/outstanding quality (3)?

Why do they sell for premium/super-premium prices (2)?

Answer 27

• Concentrating sugar in the grape must = reduction of water, which also increases concentration of acids+flavors.
• This way the wine is in balance and the sweetness does not become dominant.
• A wide range of complex flavors is added, e.g. dried fruits from VT, honey/saffron/ginger from botrytis.

$$$= high because volume is low due to less water + methods of production are expensive, e.g. hand-harvesting, special equipment + v. sugary pulp is hard to extract during pressing.

Question 28

How does drying grapes OFF the vine concentrate sugars (2)?

Where is this method commonly used (3)?

Answer 28

• healthy grapes are picked and laid out to dry (indoors/outdoors).
• this causes water to evaporate and acids/sugars/flavors to become more concentrated.

Common in Italian tradition of “passito”, e.g. Recioto della Valpolicella, Vin Santo, Passito di Pantelleria.

Question 29

How does drying grapes ON the vine affect the wine’s flavor profile?

Give a specific example:

Answer 29

• this results in very/extra ripe fruit flavors.
  e. g. Pinot Gris = stone fruit notes when ripe => tropical fruit + dired stone fruit notes when extra-ripe/dried.

Question 30

What are the 2 most common ways to stop fermentation?

Answer 30

1) chilling below 10 degrees C
2) adding a high dose of SO2 to inhibit the yeast (wine is then racked off its sediment and sterile filtered to ensure fermentation doesn’t start again later)