14.2 The Role of Wood in Maturation

Question 1

Why do newly-made wood vessels have a significant influence on the wine?

Answer 1

1. slow exposure to oxygen (old + new wood)

2. contain various extractable compounds, including tannins and many aroma compounds

Question 2

What happens to the various extractable compounds from new wood after each time the vessel is used?

Answer 2

the amount of extraction decreases because fewer extractable compounds remain

Question 3

During the first year of use, approximately what percentage of new oak flavors does a vessel use?

Answer 3

50%

Question 4

On what usage round does an oak vessel lose its effects?

Answer 4

On the 4th usage

Question 5

With what types of wines might new oak flavors be too dominant or clash?

Answer 5

aromatic grape varieties

Question 6

Is it typical to age a wine 100% in new oak?

Answer 6

No, it is typically as a proportion of the blend with wine that has been stored in pre-used barrels

Question 7

What are 4 factors that determine the level and type of compounds extracted from wood vessels?

Answer 7

1. vessel age
2. vessel size
3. type of wood
4. production of the vessel

Question 8

What are barriques?

Answer 8

• small vessels (225 l)

Question 9

What effect does size of vessel have on the wine?

Answer 9

The smaller the vessel, the greater extraction fromt he wood and greater exposure to oxygen

Question 10

What are foudres?

Answer 10

• large vessels

Question 11

What is the most common type of wood used for winery vessels?

Answer 11

Oak

Question 12

What are the main benefits of using oak as a winery vessel?

Answer 12

• can easily be shaped into a barrel
• makes containers that are watertight
• positive effects on aroma/flavour
• positive effects on structure

Question 13

Where are most winery oak vessels made?

Answer 13

• European oak (typically French, also Hungarian, Russian, Slavonian)
• American oak

Question 14

What is vanillin?

Answer 14

• contributes aromas of vanilla
• key part of the aroma/flavour in oaked wines
• found in both European and American oak

Question 15

What is the key difference between European oak and American oak?

Answer 15

American oak

• contains higher levels of lactones (aromas of coconut)
• tends to impart a greater intensity of aromas/flavours

European oak

• said to be subtler
• tends to impart more tannin.

Question 16

Which are typically more expensive: European or American oak? Why?

Answer 16

European oak is more expensive

• European oak must be split to create staves, grows significantly slower
• American oak can be sawn (much more can be made), grows significantly quicker

Question 17

What is the typical cost of an American oak barrel?

Answer 17

€300–€600

Question 18

What is the typical cost of a French oak barrel?

Answer 18

€600–€1200

Question 19

What effect does the tightness of the grain have on the resulting wine?

Answer 19

Wood with a tight grain slows down the extraction of compounds compared with coarser grained wood, and can alter what particular compounds are most extracted

Question 20

How does a tree end up with a more tightly-grained wood?

Answer 20

the result of slower growth of the tree means more tightly-grained wood

Question 21

Where do trees with the tightest grains tend to come from?

Answer 21

Continental climates

- Russia, Hungary

Question 22

Why is Hungarian oak gaining popularity in New York State?

Answer 22

• tightly-grained wood
• allows very gradual extraction of oak aroma compounds and tannins for red wines (many of which are medium in alcohol, body, tannins and flavour intensity)
• resulting wines are not dominated by oak-derived characteristics

Question 23

What other types of wood are used in winemaking?

Answer 23

• chestnut
• cherry
• acacia

Question 24

What must be done to the wood before it’s used? How long does this take?

Answer 24

• must be seasoned
• typically outdoors
• lasts 2-3 years

Question 25

What effects does seasoning the wood have on the wine?

Answer 25

• lowers humidity levels in the wood
• reduces bitter flavours
• increases some aroma compounds (e.g. those that give flavours of cloves)

Question 26

How are the barrels formed?

Answer 26

involves heating the staves so that they can be bent into shape

Question 27

How is heat used and what is the effect on the barrel?

Answer 27

• heat staves to bend them into shape

- transforms the tannins and aroma compounds in the oak

Question 28

What is toasting?

Answer 28

Refers to the temperature and length of heat exposure when wooden vessels are heated

Question 29

What are the three categories of toasting?

Answer 29

light-, medium- or heavy-toasted

Question 30

What is the effect of more toasting on the wine?

Answer 30

contributes notes of

• spice
• caramel
• roasted nuts
• char
• smoke

Question 31

For what types of wines is barrel maturation used? Why?

Answer 31

• mid-priced, premium or super-premium

- very expensive

Question 32

Why is barrel maturation so expensive?

Answer 32

• barrels are expensive
• small barrels (barriques) do not hold much liquid so many are required
• monitoring the wine in each separate barrel and performing any winemaking operations is labour intensive
• spoilage microbes such as Brettanomyces like to live in wood and therefore meticulous cleaning and sanitation is also needed
• slow process, and therefore it is not uncommon to store the wine for 1–2 years or even longer

Question 33

What alternatives to barrel maturation might producers of inexpensive and mid-priced wines choose when oak flavors are desired?

Answer 33

• oak chips: generally placed in a permeable sack, which is left to soak in the wine
• oak staves: an be attached to the inside of the stainless steel or concrete vessel, or they can float in the wine

Question 34

What are the benefits of oak chips and staves?

Answer 34

• significantly cheaper
• can choose level of toasting and seasoning
• can choose wood species
• less labour intensive
• large surface area: quick to have an effect