Week 2 - Grape growing, environment Flashcards
What 5 things do grape vines need to grow?
sunlight warmth water nutrients carbon dioxide
Describe photosynthesis:
Plant uses sunlight to combine CO2 (taken up by the leaves) and water (from the roots) to produce sugar
How are grape vine flowers pollinated?
By the wind
What is véraison?
The start of the ripening process (mid-summer), when grapes have grown larger and start to lose their dark green color. White grapes become golden and black grapes become red and purple.
What happens during the early stages of extra-ripening?
the grapes develop exaggerated ripe aromas and accumulate a higher level or sugar
What happens during the later stages of extra-ripening?
the grapes begin to turn into raisins because the water evaporates, which concentrates the acids and sugars, and dried fruit aromas start to develop.
What kind of wine is made from extra-ripe grapes?
Sweet wines, because the sugar levels are so high
Describe the grape qualities as ripening starts
high levels of acid, hardly any sugar, unattractive herbaceous flavor
Describe the grape qualities as ripening is well underway
grapes swell with water and become soft and fleshy
acidity falls and sugar rises
herbaceous flavors decrease and signature flavors develop
What is the progression of flavors in many white grapes as they ripen?
citrus fruit -> stone fruit -> tropical fruit
What is the progression of flavors in many black grapes as they ripen?
fresh fruit -> cooked fruit
True or False: European wines are made from a European species of grape, and wines in the Americas are made from a Native American species of grape.
False, only the European species of grape is used to make wine (in the vast majority of instances)
Why do grape vines go dormant in the winter?
Because they need heat and sunlight to grow
Describe what happens during flowering:
As the vine starts to grow it produces clusters of flowers. Each flower in a cluster needs to be pollinated in order to become grape.
Describe what happens during fruit set:
After it is pollinated, a grape flower grows seeds and begins to swell; at this point it is a grape. All newly formed grapes are small, hard dark green and unpleasant to taste.
What is botrytis and how does it affect grapes?
Botrytis is a fungus that causes noble rot. It makes tiny holes in the grape skin, causing the water to evaporate, thus concentrating sugars, acids and flavors of the grape.
Which of these conditions are necessary for botrytis to be beneficial?
- fungus must grow on ripe OR unripe grapes
- vineyard needs dry mornings OR damp mornings
- vineyard needs cool afternoons OR warm dry afternoons
- fungus must grow on RIPE grapes
- vineyard needs DAMP MISTY MORNINGS (so the fungus grows and spreads)
- vineyard needs WARM DRY AFTERNOONS (to limit fungus growth and prevent it from destroying the grapes)
Name 3 ways to concentrate grape sugars in the vineyard:
- extra-ripening
- Botrytis/noble rot
- Frozen grapes
Describe how icewine (eiswein) is made:
Grapes are left unpicked until they freeze in winter, then picked and pressed before they thaw. In the winery, the ice crystals and skins are separated from the remaining unfrozen liquid, which has high concentrations of sugars, acids, and flavors and produces a sweet wine with pure varietal characteristics.
What is the average growing season temperature for a “cool” climate?
62 degrees F (16.5 decrees C) or below
