The Vine Growth Cycle

Question 1

Dormancy

Answer 1

Nov - March (northern hemisphere) May - Sept (Southern Hemisphere) when average air temps go below 50 degrees. Typically starts with leaf falls in autumn and ends with budburst in spring. Since leaves fall, photosynthesis cannot occur and the vine sustains itself through the carbohydrates stored in the roots, trunk and branches.

Question 2

Budburst

Answer 2

March - April (northern hemisphere), September - October (Southern Hemisphere). When air temps are around 50 degrees, compound buds begin to develop.

Question 3

Shoot and leaf growth

Answer 3

March - July (northern hemisphere), September - January (southern hemisphere). Occurs during spring to early summer where shoots continue to grow and leaves and inflorescence (cluster of flowers on a stem) mature.

Question 4

Vigour

Answer 4

Term used to describe the vegetative vine growth, including growth of the shoots, leaves and lateral shoots.

Question 5

Flowering

Answer 5

May - June (northern), November - December (souther) Flowering describes the opening of each individual flowers within an inflorescence. Pollen lamen stamens are shed onto the stigma surface (cross pollination). Each pollen grain produces a pollen tube, which penetrate the stigma and then the ovule in the ovary. The tube delivers the sperm cells needed to create a grape, usually 4 per pollen tube.

Question 6

Fruit Set

Answer 6

Term used to describe the process from flowering to grape. Typically requires warm temperatures 79-90.

Question 7

Bud fruitfulness

Answer 7

The number of inflorescence that will develop from a bud.

Question 8

Pollination

Answer 8

Process where the pollen lamen stamens fall onto the stigma surface.

Question 9

Coulure

Answer 9

When fruit set has failed and there are more flowers than grapes. Can occur in cloudy, cold conditions when photosynthesis is less successful to produce the required carbohydrates needed to flower.

Question 10

Millerandage

Answer 10

Condition when there is a high proportion of seedless grapes, usually smaller than normal grapes and negatively effect the volume production of the wine. Can be the result of cold, wet and windy conditions during fruit set.

Question 11

Early grape growth

Answer 11

Stage right after fruit set. Hard green grapes grow in size and develop tartaric and malic acid. Some aroma compounds and aroma precursors occur during this stage.

Question 12

Methoxpyrazines

Answer 12

Aroma precursor that contributes to herbaceous aromas/flavors in some wines such as Sauvignon Blanc, Cab sav, cab franc.

Question 13

Veraison

Answer 13

Stage of the process when grape growth slows and where green colored chlorophyll in skin cells are broken down. Black grapes start to turn red.

Question 14

Ripening

Answer 14

Cells in the grape expand rapidly and sugar and water accumulate and acid levels fall. Tannins color and aroma compounds and aroma precursors develop. Typically occurs in temps 64-92 degrees.

Question 15

Extra ripening

Answer 15

When grapes are left on the vine to shrivel. Water loss through grape transpiration result in more concentrated sugars in grapes.