Viticulture Expert Guide

Question 1

What is the “Ravaz Index”?

Answer 1

the ratio of fruit weight to pruning rate
-one of the metric systems used to measure vine balance
(vegetative versus fruit growth)

Question 2

Name 4 species of the Vitis genus.

Answer 2

Vitis Vinifera* 
Vitis Rupestris
Vitis Riparia
Vitis Berlandieri
Vitis Labrusca 
Vitis Amurensis

Question 3

What is “Koshu”?

Answer 3

Japan’s signature grape
-a vinifera dominant hybrid crossed with the East Asian
species vitis davidii

Question 4

What is significant about vitis arizonica?

Answer 4

Vitis Arizonica is a grapevine species native to the southwestern US and northern Mexico. It carries a single dominant gene for resistance to Pierce’s disease and was used by Dr. Andrew Walker of UC Davis to breed 5 new grape varietals that are 97% vitis vinifera and resistant to Pierce’s disease.

Question 5

What winemaking practices are permitted in the EU’s zones A & B climate classifications?

Answer 5

Chapitalization up to 3% ABV
deacidification
No acidification
(Germany, the Loire, Champagne, Alsace, and Austria)

Question 6

TDN

Answer 6

1,1,6,-trimethyl-1,2-dihydronapthalene

Question 7

Describe the climatic diversity caused by hills and mountains.

Answer 7

Roughly, for every 300-foot gain in elevation, the temperature will decrease by about 1 degree Fahrenheit, and for every 1,000-foot increase, there is a 2% increase in sunlight exposure.

Because cold air sinks, lower-elevation bowls trap cold air and may be more frost prone. Gravity causes soil and water to run downhill, so the bottom of the hill typically has deeper soil and more available water.

(Think Grand Cru Burgundy)
Mid-slope sites are often considered best for wine quality, as they seem to have an ideal balance of soil and water conditions, along with favorable airflow to prevent frost and disease.