14. Maturation Flashcards

1
Q

What is racking (2)?

A
  • the process of transferring wine from one vessel to another with the aim of removing sediment from wine
  • wine is removed from original vessel through valve near bottom of vessel (above sediment) and poured or pumped into top of new, clean vessel
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2
Q

What is micro-oxygenation and how is it measured?

Where/when is it carried out?

What types of wines is it used for?

A
  • a process that involves bubbling oxygen through wine in units of mg/L per month
  • carried out in stainless steel tanks for a number of months post-fermentation
  • initially used for cheaper wines, now premium/super-premium wines also using
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3
Q

How does the age of an oak barrel change its effect on the wine maturing inside (3)?

A
  • New wood = more extractable compounds (tannins / aromas), stronger effect on wine.
  • Barrels lose compounds w/each usage (~50% lost after first use)
  • Very little if any compounds are extracted by wine by 4th usage.
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4
Q

What are the 3 key factors that have an impact on wine during maturation?

A

Oxygen / New Wood / Lees Contact

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5
Q

What are some things that purposeful oxygen exposure can lead to (4)?

A
  • reduction in primary aromas, increase in tertiary (e.g. dried fruits/nuts)
  • change in colour in white wines (darker colors, e.g. gold)
  • better colour stability/intensity in young reds (becoming paler/browner w/extended oxidation)
  • softening of tannins in red wine.
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6
Q

In terms of style, why would a winemaker choose to avoid new oak barrels?

What can be done instead?

A
  • New oak flavors may be too dominant / clash with natural flavors of wine (e.g. aromatic varieties)
  • Winemakers might choose to entirely use used oak barrels, or a mixture of both used and new in order to create the desired flavor profile.
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7
Q

What is an example of a wine whose high level of oxidation is a key part of its style?

How does this manifest itself in the wine (2)?

A

e.g. Oloroso Sherry

Brown color / lack of fresh fruit on palate, more nut/dried fruit flavors.

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8
Q

Why do wooden barrels of maturing wine need to be topped up (2)?

A
  • due to wine loss through pores of wooden staves.
  • prevents ullage / excessive oxidation.
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9
Q

Other than its effect on wine, why is oak the most common type of wood used for vessel construction (2)?

A
  • easily molded/shaped.
  • Creates water-tight containers.
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10
Q

What is the difference btw/ gross and fine lees?

A
  • gross lees: larger, heavier sediment particles that form quickly after end of fermentation (within 24 hours)
  • fine lees: smaller particles that settle more slowly
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11
Q

What are some ways that wine is exposed to oxygen while being matured in small oak barrels (4)?

A
  • oxygen released from pores in barrel
  • gaps between staves
  • bung hole
  • during transfer of wine e.g. racking, topping up through bunghole.
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12
Q

Explain how oxidation leads to greater color stability and intensity in young red wines (2):

What is an example of a wine that particularly benefits from this process?

A
  • In this reaction, anthocyanins (color compounds) bind w/tannins.
  • This protects anthocyanins from being absorbed by yeast lees or bleached by SO2.

Particularly important for lighter-colored red wines, e.g. Pinot Noir.

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13
Q

Why do some winemakers blend wine for PRICE (2)?

A
  • inexpensive wines may see blending of parcels to increase profitability.
  • e.g. more expensive Chardonnay may be blended w/cheaper Trebbiano/Semillon to increase volume and decrease price.
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14
Q

What is “autolysis”?

What is “bâtonnage”?

A

Autolysis: The slow death / breaking down of lees and the release of compounds that result.

Bâttonage: Stirring of the lees.

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15
Q

Why do some winemakers choose to store newly fermented, finished wine in bulk instead of bottling it (4)?

A
  • wines are bottled only when a customer has placed an order.
  • more flexibility in terms of selling wine (using different labels / selling in bulk / blending w/other wines)
  • more efficient use of space
  • wine labels less likely to get dirty/ruined by humidity.
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16
Q

What is meant by “toasting” wood (2)?

What effect does this have on the wood?

What effect will this have on the wine?

A
  • Toasting is heating wood staves so they are maleable and able to be bent into shape.
  • Temp + length of heat exposure = “level” of toasting (low/medium/heavy-toasted)
  • transforms tannins + aroma compounds in oak.
  • contributes notes of spice, caramel, char, smoke.
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17
Q

What are some reasons for NOT blending wines (4)?

A
  • legal restrictions on blending varietals/geographical areas.
  • production of single vineyard wines to maintain character/quality.
  • promotion of single vineyard vines = more rare/distinctive for marketing purposes.
  • some varietals have signature characteristics that a winemaker would want to preserve, e.g. Sauvignon Blanc/Riesling.
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18
Q

What does the term “blending” usually refer to?

When can it take place?

A
  • The mixing together of two or more batches of wine.
  • Can take place any time, but most commonly just before finishing/packaging.
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19
Q

Give a specific example of where a specific type of oak barrel is used due to its grain-tightness (4):

A

Hungarian oak barrels are becoming more popular in NY State.

  • Hungarian oak tends to be tighter-grained, allowing for a very gradual extraction of oak aroma compounds and tannins.
  • This is appropriate for red wines produced in NY because they are usually medium in alc, body, tannins and flavor intensity.
  • This leads to them not being dominated by oak-derived characteristics.
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20
Q

What temperatures are reds and whites stored at during maturation?

A
  • whites: 8-12 C / 46-54 F
  • reds - 12-16 C / 54-61 F
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21
Q

Why does barrel maturation add to the cost of a wine (3)?

A

1) Expensive (small barrels = small amount of wine = more barrels must be paid for)
2) Monitoring each barrel / racking / cleaning = $$$for labor
3) V. slow process = wine can be stored for years = return on investment is slow, which increases premium.

22
Q

3 types of wood other than oak used for wine barrels:

A

Cherry / Chestnut / Acacia

23
Q

Why do some winemakers blend wine for BALANCE (3)?

A
  • to increase/moderate levels of characteristics w/intention to enhance quality.
  • e.g. a batch of wine from a warmer vineyard blended w/a cooler vineyard can fine tune acid/alcohol levels.
  • different grapes provide different qualities, e.g. in Bordeaux, Merlot = more body+riper, plummy fruit blended w/Cabernet Sauvignon = tannin+structure.
24
Q

Why do some winemakers blend wine to MINIMIZE FAULTS (2)?

A

e. g. a barrel of wine might show significant VA.
- therefore it may be sterile-filtered to remove acetic acid bacteria and blended w/un-faulty wine to lower concentration/perception of the VA.

25
Q

What is meant by “seasoning” wood used for barrels?

Why is this done (3)?

A
  • Wood is left outside to dry for 2-3 years.
  • This lowers humidity levels in wood, reduces bitter flavors and some aroma compounds.
26
Q

What are the different ways in which wines can be blended (6)?

A

1) different grape varieties.
2) different locations (vineyards/regions/countries)
3) different growers
4) different vintages
5) different methods of vinification (e.g. free run juice/press juice/oak-aged)
6) different vessels e.g. different barrels of wine

27
Q

Why is wine loss through wooden barrels undesirable from a winemaker’s perspective (3)?

For these reasons, how are maturing wines usually stored?

A
  • Reduces volume of wine to sell
  • Requires more frequent topping up = $$$ for labor + risk of oxidation.
  • Can lead to higher alcohol concentration in wine if humidty is low (alcohol loss rate is slower than water’s)

Wines are usually matured in cool, humid conditions e.g. underground cellars.

28
Q

Besides removing wine from its lees, what effect does Racking have on wine?

How can a winemaker respond to this effect (2)?

A
  • Racking can also be an oxidative process

Winemakers can:

  • increase oxygen exposure by purposely splashing wine
  • decrease exposire by using pressure from inert gas to push wine through a hose and into a new vessel (preferable for fruity/aromatic wines)
29
Q

How does the size of the barrel affect its level of extraction by the wine inside it (2)?

What are examples of a small and a large barrel?

A
  • Small barrels = more extraction of flavors
  • This is because it has a greater surface area : liquid ratio, meaning a higher proportion of the wine is in contact w/the wood.

Barrique (225L) vs Foudres (typically > 1000L)

30
Q

What are common pre-bottling maturation periods for red and white wines?

Why are they different (2)?

A

Red: 12-24 months

White 6-12 months

Red wines can withstand oxygen exposure for longer than white wines before showing signs of oxidation; this is due to their higher content of anti-oxidative phenolic compounds e.g. tannins.

31
Q

What is the most traditional, common method of gradual oxygen exposure?

A

Aging in small wooden vessels.

32
Q

Why are European oak barrels more expensive to produce than American (2)?

What is the general price range of each kind?

A

1) American oak trees grow significantly quicker, replaced faster.
2) European oak is tighter-grained = must be split, whereas American oak can be sawn. This means you can produce more American barrels than European from the same amount of wood.

European barrels are roughly DOUBLE the price (€300-€600 for US vs €600-€1200 for European.)

33
Q

Besides excessive oxidation, why must care be taken when increasing oxygen levels in wine?

A

Increased oxygen levels = more favorable environment for spoilage microbes, e.g. acetic acid bacteria + Brett.

34
Q

What factors influence the speed of oxidation (3)?

A
  • amount of oxygen exposure (fully-exposed vs large oak vats)
  • color of wine (red wines can withstand higher levels of oxy exposure than white wines)
  • temperature (warm temps increase rate of oxidation)
35
Q

What are 2 alternatives to oak barrel aging that still add oak flavor?

What are the advantages of these (5)?

A

Oak chips (placed in a permeable sack to soak)

Oak staves (floating / attached to inside of vessel.)

1) Much cheaper than barrels.
2) Less labor intensive
3) Quicker to take effect (large surface area)
4) Amount can be fine-tuned for desired effect.
5) Can be used in conjunction w/micro-oxygenation to mimic barrel aging.

36
Q

Why do some winemakers blend wine to increase VOLUME (2)?

A
  • areas w/small vineyard holdings = necessary to blend vineyards to produce a viable amount of wine.
  • in poor vintages, low yields may necessitate purchasing wine/must.
37
Q

Why do some winemakers blend wine for CONSISTENCY (2)?

A
  • to avoid bottle variation of the same product.
  • some styles require consistency across different years e.g. Sherry / NV Sparkling / inexpensive wines.
38
Q

What are some effects of lees aging on the character of the wine (6)?

A

1) releases compounds that contribute to flavours, body and texture
2) binds with and softens astringency of tannins
3) helps in stabilization of wine against proteins that cause hazes
4) provide nutrients for microbes (helps with Malo but can assist in development of spoilage microbes)
5) reduces color
6) helps to protect wine from oxygen

39
Q

What is the relationship of lees to microbial growth (2)?

A
  • Lees provides nutrients for microbes = growth of lactic acid bacteria.
  • Also encourages development of spoilage microbes e.g. Brett.
40
Q

What does “lees” refer to?

What is it made of (5)?

A
  • refers to the sediment that settles at the bottom of a wine vessel.
  • dead yeast, dying yeast/bacteria, grape fragments, precipitated tannins, nutrients, etc.
41
Q

What can happen if the layer of lees in a maturing wine is too thick (4)?

A
  • Volatile, reductive sulfur compounds can be produced.
  • At low concentrations can add complexity (e.g. notes of struck match/smoke)
  • If not controlled, these compounds = unpleasant aromas e.g. rotten eggs.
  • This is known as “reduction”
42
Q

How does the grain-tightness of an oak barrel affect its level of extraction on the wine maturing inside it (2)?

What regions produce barrels like this?

A
  • Slower, more gradual extraction of compounds + tannins vs coarser-grained wood.
  • Alters which particular compounds are extracted.
  • Barrels made from trees grown in continental climates e.g. Russia/Hungary.
43
Q

How does the blending process start?

What does it require?

What makes it challenging (2)?

A
  • Usually starts w/blending trials using small volumes of wines to distinguish proportions to be used.
  • Requires high level of skill/experience
  • Blending young wines meant for aging challenges winemaker to estimate how the blend will develop in the future.
  • money is lost if wines are not used/sold.
44
Q

Why do some winemakers blend wine for COMPLEXITY (2)?

A
  • blending of different parcels/barrels/varietals may lead to greater range of flavors

=> higher complexity + quality.

45
Q

In terms of legality, what determines whether wines can be blended or not (3)?

A
  • Different countries/regions have different restrictions regarding blending of different grapes/vintages, etc…
  • e.g. in EU, wine with a PDO can only contain grapes from that geographic area.
  • diferent PDOs allow/disallow blending, e.g. Brunello = 100% Sangiovese, Chianti Classico = min. 80% Sangiovese+20% other varieties.
46
Q

What are 2 examples of wines that might be finished and bottled immediately following fermentation, with no maturation?

How will they be stored between the end of fermentation and finishing?

Why?

A

NZ Sauvignon Blanc / Veneto Pinot Grigio

  • stored in impermeable tanks e.g. stainless steel, protected with SO2 and/or blanketed w/inert gas.
  • meant to preserve youthful, fruity aromatic style.
47
Q

Without going into details, what are 7 reasons for blending wine?

A

1) Balance
2) Consistency
3) Style
4) Complexity
5) Minimizing faults
6) Volume
7) Price

48
Q

What are differences btw/ European and American oak maturation in terms of:

FLAVORS

TANNIN

PRICE

GRAIN

A
  • both have high vanillin, but American has high lactones (coconut) - European is more subtle
  • European oak imparts more tannin
  • European oak is more expensive
  • European oak is tighter-grained
49
Q

Why might lees aging increase a wine’s cost (2)?

Give a specific example of where is this the case:

A
  • Increases time the wine is stored at the winery.
  • Needs to be monitored / stirred = $$$ labor
    e. g. acceptable / good inexpensive Rueda wine = packaged + released shortly after fermentation.
    vs. higher quality+$ Rueda = aged in tank on lees for a few months
50
Q

How is wine lost during maturation in wood vessels (2)?

What types of vessels lose more wine?

Why?

What other conditions can increase the rate of wine loss (2)?

A
  • water+alcohol impregnate wood.
  • they turn into vapor and diffuse to the air outside vessel.

Smaller barrels lose wine at a faster rate than large ones because the surface area : volume ratio is larger.

Low humidity + warm temps increase rate of wine loss.

51
Q

What are benefits of micro-oxygenation (5)?

A

1) increases colour intensity/stability
2) softens tannins
3) improves texture
4) reduces presence of unripe, herbaceous flavours
5) quicker / cheaper / more controllable than barrels