Viti 4: The Grape

Question 1

Skin also known as…

Answer 1

Epidermis

Question 2

Thin waxy layer known as…

Answer 2

Cuticle

Question 3

Pulp:

Answer 3

Large cells with thin walls. Vacuoles with juice inside.

Question 4

Peripheral pulp:

Answer 4

Coloured pigments, tannins and flavour constituents.

Question 5

Intermediate pulp:

Answer 5

For sparkling wines (clear, low flavour, low tannin).

Question 6

Seeds:

Answer 6

Embryo and albumen (feeds embryo in germination). Tannins present.

Question 7

Constituents:

Answer 7

Water (ca. 80%), sugars and other carbs (ca. 20%), acids (ca. 1%) and phenolic compounds (ca. 0.1%).

Question 8

Preference of most yeasts:

Answer 8

Glucose. Fructose lifts in late harvest, fermentation can be difficult.

Question 9

Pectins:

Answer 9

Complex carbs. Makes clarification and extraction difficult. Pectolytic enzymes needed. High in aromatics like Gewürz and Viognier.

Question 10

Main acids:

Answer 10

Tartaric and malic (organic because they contain carbon atoms). Stop microbial spoilage and make wine taste ‘crisp’.

Question 11

Other acids in must:

Answer 11

Citric, ascorbic and acetic.

Question 12

Phenolic compounds:

Answer 12

Catechins and epicatechins can be astringent, waxy. Tannins are antioxidants and preservatives. Anthocyanins in reds.

Question 13

Grape development phases:

Answer 13

1. Herbaceous. 2. Véraison (skin becomes elastic, berry itself stops photosynthesising). 3. Maturation (40-60 days, maximum diameter and sugar). 4. Sur-maturation (shrivelling with loss of water, max water and vascular bundles stop working).