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WHAT'S UP IN THE VINEYARD AND CELLAR

The impact of wine cellars on global warming

Charl Theron

"Unchecked climate change will be an environmental and economic catastrophy but above all it will be a human tragedy. It is absolutely vital that international action is taken now to avoid dangerous climate change."
Achim Steiner, Executive Director of the UN Environment Program

Global warming occurs as a result of gases such as carbon dioxide and methane that are released into the atmosphere, thereby increasing atmospheric temperature. Industry has to shoulder the blame, but our daily lives are also responsible, whether the impact is direct or indirect. In the USA 21% of carbon dioxide pollution, for example, occurs as a result of actions that have to be taken to supply the domestic energy consumption. Emission gases of motor vehicles also contribute to global warming and cars differ in their contribution to the release of global warming gases. A well-known car such as a 2006 C230 manual Mercedes Benz "produces" 4.268 tons of carbon dioxide if it clocks 20 000 km per annum (www.lenntech.com).

A recent UN report predicted the following shocking consequences if global warming should continue:

  • Food shortages for 130 million people by 2050.
  • Drought and higher sea levels in Australia and New Zealand by 2030.
  • Threatened survival of eco-rich sites such as the Great Barrier Reef.
  • Approximately 100 million people will be exposed to oceanic floods each year, if the sea level rises by 1 to 3 mm annually.
  • Veld fires and heatwaves will occur with greater frequency.
  • Coral reefs and fishing will undergo drastic changes (www.livescience.com).
These statistics appear to be far removed from the wine industry, but closer investigation reveals shocking facts. Temperature increases have obvious implications for cultivar suitability and viticultural practices, but it is not the purpose of this article to deal with such matters.

Wine cellars are already and will be held more and more accountable for their environmental standards. The cultivation of grapes and subsequent vinification use considerable resources such as water, electricity, fuel, chemicals and vehicles and consumers increasingly question the impact thereof and of the so-called "food miles", the distance from the cellar to the consumer, on the environment. A recent report by the British Department for Environmental, Food and Rural Affairs calculated that the "food miles" increased by 15% between 1992 and 2002. Supermarket groups are urged to buy from so-called "carbon neutral" suppliers (The Age, 2007).

Just such a "Carbon Neutral" programme was initiated in Australia in 2001 and producers and wine cellars were requested to plant specially selected plants so as to neutralise the influence of the global warming gases that had been emitted (Corsey, 2007).

Backsberg Estate, which recently acquired carbon dioxide neutral status, has an emission of 1 590 tons of carbon dioxide annually to the atmosphere as a result of its activities. This was calculated taking into account the energy consumption on the estate, wine fermentation, transportation of products, marketing trips, transport of packaging material and other resources. To neutralise the influence of these carbon dioxide emissions, one tree will be planted for each 2 tons of emitted carbon dioxide (Nellie Brand, 2007).

The alcoholic fermentation process of wine obviously has a significant influence on the release of carbon dioxide into the atmosphere, seeing that carbon dioxide is one of the natural by-products of the process. The extent thereof in South Africa only becomes apparent when the following calculations are done:

The alcoholic fermentation process is formulated as follows by the Gay Lussac formula of 1810:

1 Molecule Glucose or Fructose > 2 Molecules Ethanol + 2 Molecules Carbon dioxide + Energy - 180 g Glucose or Fructose will theoretically produce 88 g Carbon dioxide.

The relationship between °Balling and actual sugar content in g/litre can be obtained from tables and 20°B for example is the equivalent of 191 g sugar/litre.

If one ton of grapes is pressed at a sugar content of 22°B and 750 litres of juice thus recovered, ca 79 kg of carbon dioxide are formed during the alcoholic fermentation process.

If the South African industry produces 710 million litres of drinkwine, 82 million litres of wine for brandy and 150 million litres of distilling wine at an average alcohol content of 12% A/V per annum, ca 94 000 tons of carbon dioxide will be formed annually during the alcoholic fermentation (Sawis statistics, 2007).

One could argue that the consumption of carbon dioxide by the vines during photosynthesis theoretically neutralises this formation of carbon dioxide, but it is doubtful whether this is likely to be achieved in practice (The Age, 2007).

The above facts are not intended as a threat or a warning, but rather to raise awareness among wineries about this topic. Actions that should receive attention from cellars, are the following:

  • A planting programme of indigenous trees that could also contribute to the image of cellars. More or less five trees are required to neutralise the influence of one ton of carbon dioxide. There are, however, differences of opinion as to the number of trees to be planted per ton of carbon dioxide.
  • An optimal cellar waste management programme.
  • The use of cold air outside the cellar in cooling systems.
  • The reduced use of plastic.
  • The use of thinner glass bottles and consequently smaller cartons thus implying more bottles per export container.
  • The more effective and economical consumption of electricity in the cellar.
  • The use of energy saving bulbs.
  • The more frugal use of fuel during the transport of the grapes to the cellar.
  • The possible use of biofuel.
  • The use of more environmentally friendly sources of electricity such as solar power where applicable.
Discussions are currently under way to investigate the establishment of a South African wine industry "Carbon Neutral" programme.

References:

1.Brand, Nellie. 2007. Backsberg se bome help vergoed vir CO2. Sake 24, Friday, 30 March 2007.
2.Corsey, Lauren. 2007. Carbon neutrality creating a rejuvenated landscape. Austr Viticulture, March/April 2007: 62 - 63.
3.Sawis statistics. 2007. Personal communication.
4.The Age, Australia. 2007. Red, white and green, 27 February 2007.
5.www.lenntech.com.
6.www.livescience.com.

Wynboer is incorporated in WineLand, magazine of the SA wine producers.

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