Yield Flashcards
Past exam questions
2013: Many factors affect flowering and fruit set. Examine what effect these might have on quality and yield.
2004: Restricted yields have traditionally been an important requirement in the making of high quality wines. Have modern viticultural methods reduced this requirement?
1997: How do commercial objectives affect the yield of a vineyard? Describe the methods by which a viticulturist can control that yield.
1995: How important is the yield of a vineyard? Compare the relative significance of yield per hectare and yield per vine, and draw conclusions as to the best methods of controlling crop levels.
1991: Many vineyard regions have produced record harvests in recent years. What is the effect of yield on quality and life of the wine? Do you that modern viticultural improvements have superseded the need for smaller crops?
1991: You have recently planted a new vineyard on fertile soil. Early tastings reveal an excessively vegetal or herbaceous character in the wines. To what do you attribute this problem and how will you attempt to eliminate it?
Examples
NAPA:
- Screaming Eagle upped their yields to around 4 tons per acre, they find they don’t have to green harvest now and the wines have better natural freshness.
- Per Kelly Maher, for high quality wine, 2/1/2/1 clusters per shoot is ideal so long as none of the clusters are touching. - Sometimes Maher does 2x cluster per shoot with de-winging
- Maher says target for green drop is 5-10% (he debuds the lower bud for sap flow purposes)
- Harlan is 2 - 2.5 tons/acre
- Larkmead is 2.5 - 3 tons/acre
- Round Pond is a divided canopy with wires around 10 tons/acre
YIELDS AND PYRAZINE
- Steve Matthiasson says sometimes lower yields increase pyrazines because fewer buds = more shoot vigor (elaborates that it is not sufficient to fruit thin, you must divigorize the whole plant – deficit irrigation or dry farming, eliminating nitrogen fertilizer, more cover crops, more buds at pruning, higher yields)
- methoxypyrazines (MPs) a class of odorant that can be detected 1ppt
- MPs are located in skins, stems, and rachis (also beatles and ladybugs)
- light exposure lowers MPs
OREGON:
- Hiyu does not prune, but own-rooted old vines naturally regulate yield.
BORDEAUX:
- Michel Rolland famous for mandating one cluster per shoot
BURGUNDY:
- Grand Cru max yields run from 35 hl/ha 48z hl/ha
- Cotes de Beaune-villages max yield 50 hl/ha
Facts RE Yield
- water stress between bud burst and flower set can reduce cluster #s
- high density vineyard can have same overall yield as low density vineyard, but as there is less fruit per vine the quality will be higher
- Quadrilateral training that pushes vines for high yields can exhaust a vine and shorten its life span
