The Role of Oak in Maturation

Question 1

What effect does the age of an oak vessel play in maturation?

Answer 1

New oak contains extractable flavor compounds. It loses 50% during the first use, and by its fourth uses, it adds no flavor.

Question 2

What size is a barrique oak vessel?

Answer 2

225L

Question 3

What impact does the size of a barrel have on wine as it matures?

Answer 3

Smaller barrels have a higher wood to wine ratio.

Extraction of flavors from the wood and exposure to oxygen will be greater.

Question 4

Why is oak favored as the wood material for wine vessels?

Answer 4

• it can be easily shaped into a barrel
• it is strong
• it makes water-tight containers
• it gives positive flavors
• it has positive effects on the structure of the wine

Question 5

What are the main species of oak?

Answer 5

• American
• European

Question 6

Which compound, common to both American and European oak, contributes a key part of the oaked wines’ flavor profile?

Answer 6

Vanillin (the same compound is found in vanilla pods)

Question 7

Which type of flavor compounds does American oak typically have more of than European oak?

Answer 7

Lactones: give a coconut flavor

Question 8

What structural component does European oak give to the wine more than American oak?

Answer 8

Tannin

Question 9

Why are European oak barrels more expensive than American oak barrels?

Answer 9

The production process is more costly for European oak. European oak must be split, whereas American oak can be sawn, which wastes less wood.

American oak trees grow more quickly than European oak.

Question 10

How does the grain of the wood play a part in the way oak vessels interact with the wine?

Answer 10

The tighter the grain of the wood (from trees that grow more slowly), the slower the release of flavor compounds into the wine.

Question 11

What other woods can be used to make wooden wine vessels?

Answer 11

Chestnut, cherry, and Acacia are occasionally used.

Question 12

How long is oak usually seasoned before it is turned into barrels?

Answer 12

2-3 years

Question 13

What effect does seasoning have on the oak?

Answer 13

• reduces bitter flavors
• reduces humidity
• increases desirable flavors like clove

Question 14

What effect does heating the wood have?

Answer 14

• allows for the wood to be bent into the shape of a barrel
• transforms the tannins and aroma compounds in the oak
• produces desirable flavors in the oak

Question 15

What effect does the temperature and length of heating have on the oak?

Answer 15

This is called toast level.

Toasting contributes spice, caramel, roasted nuts, char, and smoke flavors.

Toast level can be light, medium, or heavy.

Question 16

What effect does the length of maturation time in wood have on the wine?

Answer 16

The longer a wine is aged in a wooden vessel, the greater the extraction of compounds and the greater the exposure to oxygen.

The longer the wine is aged in wood, the greater variety of flavors extracted.

Question 17

Why is maturation in oak vessels expensive?

Answer 17

• barrels themselves are expensive
• small barrels do not contain a lot of liquid, and so more are required
• monitoring the wines in individual barrels is labor intensive
• higher risk of contamination with spoilage organisms
• slow process, so slow return on investment

Question 18

What are alternatives to oak vessels for maturation?

Answer 18

Producers of inexpensive wines might use oak chips or staves.

Question 19

What are disadvantages of oak staves and chips for maturation?

Answer 19

There is no oxygen penetration, which is possible from the use of oak barrels, so micro-oxygenation is often used to replace this.