WSET Advanced Chapter 2 The Growing Environment AKC2 Flashcards
Climate and Weather
Climate is the pattern of rainfail, temperature and sunlight averaged out over several years, and it can change over decades. Weather is the annual variation in those averages. In Bourdeaux, there is great variation in rainfall from year to year, while in California’s Central Valley, it is always dry and hot.
Vine Temperatures
Ideal average growing temperature is between 16 and 21 Celsius. Vines go dormant at 10C and begin to die over 22C. Temperature dictates which varietals to grow – Riesling thrives in cool locations, while Grenache needs it to be hot.
Temperature’s Affect on Vine Growth
Cooler: Later budburst, shorter growing season for grapes to ripen, flowering and fruit set can be disrupted, higher acid / lower sugar production. Black grapes may produce bitter/astringent flavors. Better for whites.
Factors Affecting Annual Temperature
Latitude: Vines grow between 30 and 50 degrees latitude, North and South of the equator.
Factors Affecting Continentality
The variation between summer and winter temps is mitigated by large bodies of water. Inland areas suffer larger swings. Niagara viticulture would not be possible without Lake Ontario.
Factors Affecting Diurnal Range
Water: Seas and lakes are the biggest factors that limit the temperature change between day and night, but rivers and streams also have an impact.
Importance of Diurnal Range
Cool Nights help the vine rest and extend the growing season. They also help slow the loss of volatile aromas during ripening.
Characteristics of Wines from High and Low Diurnal Range Regions
High Diurnal Range Wines: Fresher and More Aromatic
Winter Freeze
If the temp falls below -20C, vines can be seriously damaged or killed, particularly the Graft Callus. One solution is to bury the callus, or the whole vine.
Spring Frosts
Occur when air below 0C collects at ground level, freezing water vapor and killing newly-burst buds and shoots, impacting yields significantly.
Four Types of Spring Frost Protection
Burners: Generating heat through combustion, creates movement in the air and prevents frost. Smudge pots create smoke that stays on the ground and acts as insulation.
Mild Winters
Mild Winters can prevent vine dormancy, resulting in multiple low-quality crops per year. The vine’s life will be shortened and vineyard pests will multiply year-round.
High Temperature Summers
Accelerate the ripening of grapes, altering the composition of the grape and the style of the wine. There is also drought risk, which would cause the vine to shed leaves and even die.
Sunlight - Importance and Hazards
Importance: Sunlight is needed for photosynthesis, and the more of it there is, the more glucose is generated.Grapes ripen better if exposed to direct sunlight.
Factors Affecting Sunlight
Seas And Lakes: Bodies of water create cloud cover. Landlocked regions are sunnier. Some bodies of water will reflect sunlight.