14. Maturation

Question 1

What are some things that oxidation leads to?

Answer 1

• reduction in primary aromas, increase in tertiary
• change in colour
• better colour stability/intensity in young reds

Question 2

What is micro-oxygenation?

Answer 2

• 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
• usually used in cheaper wines

Question 3

What are benefits of micro-oxygenation?

Answer 3

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

Question 4

What temperatures are reds and whites stored at during maturation?

Answer 4

• whites - 8-12 degrees

- reds - 12-16 degrees

Question 5

What are some differences between European and American oak?

Answer 5

• both have high vanillin, but American has high lactones (coconut)
• European is more subtle, but imparts more tannin
• European is more expensive
• American grows quicker

Question 6

What are lees made up of?

Answer 6

• dead yeast, dying yeast/bacteria, grape fragments, precipitated tannins, nutrients, etc.

Question 7

What are gross and fine lees?

Answer 7

• gross: sediment that forms quickly after end of fermentation (within 24 hours)
• fine: smaller particles that settle more slowly

Question 8

What are some benefits of lees aging?

Answer 8

1) release compounds that contribute to flavours, body and texture
2) reduce colour and soften 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)

Question 9

What is racking?

Answer 9

• 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