Biophysical Constraints

Factors affecting the nature, spatial patterns and future directions of the global viticulture and winemaking industry

There a number of biophysical factors that plays an influential role when determining the character of a specific wine.

Characteristics such as soil, slope, aspect and climate influence the types of wine produced and its character.

Climate (refer to sheets written in class also)
  • Climate factors determine the spatial distribution of grape growing on a global scale. Climate determines the length of grape growing season, the rate of plant growth and the quantity and quality of the fruit. Within the range of suitable climates, particular species are best able to tolerate more specific climate types.
  • Temperature:
    - Ideal temp. Is 19 degrees for white grapes and 21 degrees for red grapes
    - If the average is below 10 degrees Celsius the vines may not produce grapes suitable for winemaking.
    - At ideal temp. the grapes produce sugar needed for plant growth, which influences flavor and colour.
  • Sunlight:
    -The level of solar radiation determines the rate of photosynthesis that occurs.
    - Plant growth is influenced by sunlight that a plant recieves.
    - The aspect of the slope is crucial on which grapes are grown. In southern hemisphere north facing and west facing slopes receive more direct sunlight than slopes facing east and south.
    - This case is opposite in the northern hemisphere.
  • Wind:
    - Excessive wind speeds have the ability to severely damage grapes.
    - Winds cause erosion, which removes topsoil, exposing root systems. This exposure inhabits the vine’s ability to obtain moisture from the soil, stunting vine growth.
  • Frost:
- Vines are damaged by frost when temp. drop below -1 degrees celcius.
- This often occurs in late autumn and early spring, or bud burst period.
- Best time for frost to occur is when vines are dormant, during winter.
- Soil management, irrigation and vine training patterns can be used to eliminate frost damage.
  • Rainfall:
- Vines generally need an average rainfall of approx. 700mm a year
- Majority of wine areas in Australia receive less than this
- Irrigation is widely used to replace natural rainfall
- A reliable supply of water is crucial to its viability.
- Heavy rainfall, especially in summer can cause major problems: erode soil, damage and even strip the ripening fruit from the vines and promote the development of disease.
- The water budget of any wine growing region depends on the rate of evaporation, hours of sunlight, aspect and topography
- A reliable supply of water, especially in dry regions is a problem via the use of irrigation technologies.
- Irrigation water can come from rivers, streams, bores, wells, springs, dams or in public supply.

Topography
  • In relation to topography climate plays a crucial role in determining the minor character of the grapes and thus the wine.
  • Elevation, aspect and inclination of the vineyard plays a crucial role.
  • Many vineyards are located on undulating to steeply sloping land.
  • They are planted on contour banks to prevent erosion and to reduce the intake of water from rainfall.
Soil
  • The nature of soil depends on the parent material and the physical chemical and biological processes of weathering.
  • The composition of the parent material will influence the properties of soil and thus the character of the wine.
  • Soils suitable for viticulture are generally fertile of deep.
  • The depth of the soil assists with development of the wine’s root system.
  • Shallower and dryer soil is better for producing quality wines.
  • Soil determines the character and quality of a wine by influencing the water supply and temperature in and above the soil. In hot dry areas the criteria for evaluting soil differs from those in cool wet areas.

Pests and Diseases
  • APHID
    - The aphid that was the central source of the damage in France was first noted following the growing of the European vine Vitis vinifera by French colonists in Florida in the 16th century.

    - These plantations were a failure, and later experiments with related species of vine also failed, although the reason for these failures appears to have been a mystery to the French colonists.
    - It is known today that it was a species of North American grape phylloxera that caused these early vineyards to fail; the venom injected by the Phylloxera causes a disease that is quickly fatal to the European varieties of vine.
    - The aphids went relatively unnoticed by the colonists, despite their great numbers, and the pressure and difficulty of successfully starting a vineyard in America at the time.
    - It became common knowledge among the settlers that their European vines, of the vinifera. variety, simply would not grow in American soil, and they resorted to growing native American plants, and established plantations of these native vines.
    - Exceptions did exist; vinifera plantations were well-established in California before the aphids found their way there.
  • Phylloxera
    - There have been several theories proposed for why the phylloxera was ignored as the possible cause of the disease that resulted in the failure of so many vineyards, most of which involve the feeding behaviour of the insect, and the way it attacks the roots.

    - The proboscis of the grape phylloxera has both a venom canal from which it injects its deadly venom and a feeding tube through which it takes in vine sap and nutrients.
    - As the toxin from the venom corrodes the root structure of a vine, the sap pressure falls and, as a result, the Phylloxera quickly withdraws its feeding tube and searches for another source of food.
    - Thus, anyone digging up a diseased and dying vine will not find Phylloxera clinging to the roots of the plant.
  • Journey to Europe
    - For a few centuries, Europeans had experimented with American vines and plants in their soil, and many varieties were imported from America without regulation, disregarding the possibility of pest transfer, and related problems.
    - Jules-Emile Planchon, a French biologist, who identified the Phylloxera in the 1860s, maintained that this transfer of American vines and plants into Europe greatly increased between roughly 1858 and 1862, and this is how the Phylloxera was accidentally introduced to Europe around 1860, although the aphid did not enter France until around 1863.
    - It is believed that the introduction of the blight-causing Phylloxera was not a problem before the advent of steamships, which were faster and hence allowed the Phylloxera to survive the quicker ocean voyage.

Socio-cultural factors
  • The global pattern of wine consumption is changing per captia consumption is falling in the traditional wine consuming countries (France, Italy, Spain) while increasing countries such as the UK, US, Canada, Russia and Asia.
  • The increase in wine consumption has largely been at the expense of beer and spirits rather than a net increase in alcohol consumption/per person.
  • Level and rate of income growth
    - Rising incomes and changing preferences incourage depend in the UK and the US
    - Demand in Russia and China is driven by the mergants of the middle class, improving living standerds and rising disposable incomes and the gradual “Westernisation” of the lifestyle of younger consumers.
    - French Italian and Spanish consumers have cut wine consumption over several decades despite rising incomes.
    - In France annual per capita wine consumption has declines from 160 Litres in 1965 to 70L in 2005. The decline has been noticeable in the 19-24 year old age group. Proportion of this age group who are regular wine drinkers fell from 24% in 1980 to 4% in 2000.
  • The process of cultural convergence:
    - The process is of advances of global communication and trade.
    - Increasing globalised industry users advance marketing techniques to sell branded wine to a global market.
  • The age structure of the population:
    - Rates of wine consumption are highest in 35-65 years age group.
    - The number of younger people and proportion of people who drink wine are critical to the future of the industry.
    - This explains the difficulties being experienced in the traditional win markets where young people seem to have it preference for alternative alcoholic beverages.
  • Changing consumer tastes and life style expectations
    - Wien is increasingly being adopted as the most appropriate alcoholic beverage to drink at home and in restaurants.
    - Increase proportion of young couple without children are eating out more often and are spending more on wine.
  • Marketing and licensing laws:
    - In the UK the promotion of new world wines has seen a decline in sales of French and Italian wines and a growth in those in Australia, California and Chile.
    - Less stringent licensing laws, introduced in 2005, are expected to increase win sales through bars and restaurants.
  • Potential health benefits:
    - Increasing consumer interest in its potential health benefits has also driven growth in wine consumption.
    - Polyphenols occurring in red wine reduce the risk of heart disease, stroke and cancer, with possible beneficial effects for those suffering from muscular degeneration and Alzheimer’s disease.