Appendix A: The Grapevine

Question 1

Within what latitude does the grapevine thrive?

Answer 1

Between 30 & 50 degrees north & south latitude.

Question 2

What are the 3 major nutritional needs of the grapevine?

Answer 2

1) Nitrogen
2) Phosphorus
3) Potassium

Question 3

What are the 6 minor nutritional needs of the vine?

Answer 3

1) Boron
2) Copper
3) Iron
4) Magnesium
5) Manganese
6) Zinc

Question 4

What happens if soils are nitrogen deficient?

Answer 4

It results in nitrogen deficient musts.
The yeast needed to ferment grape must into wine are 75% nitrogenous. Yeasts need nitrogen to multiply.
Lacking sufficient nitrogen in the juice, yeasts end up scavenging for it. They break apart amino acids (the building blocks of proteins) in order to release the nitrogen bound within these molecules. In so doing, sulfur is also released, which ends up incorporated into light sulfides as fermentation continues.

Question 5

What characteristics are produced in wines that are made from nitrogen deficient musts resulting in the creation of light sulfides?

Answer 5

Unmistakable aromas of toasted almond and roasted hazelnut.

Question 6

How do Old and New World winemakers approach winemaking with nitrogen deficient musts?

Answer 6

Old World winemakers allow this natural process to occur as it represents the signature of their soil.

Many New World winemakers opt to add yeast nutrients so as to avoid light sulfides, making a subtle yet significant change to the natural flavour profile of the finished wine.

Question 7

What soils are nutrient deficient?

Answer 7

Limestone/chalk