There are some great tasting food recipes people can eat that are both healthy for the body and good for an increasingly water stressed planet. Why go to the trouble? Because how we choose to eat right here and right now will affect the lives of people and habitats elsewhere on the planet and in years ahead. Take the following numbers, estimated by from Waterwise... Importance of embedded water in food
Water embedded in food represents the majority
(65%) of total water use. While the exact figure may be
disputed it is clear that significant amounts of water are used in the
production and processing of food products. The amounts vary by food
category. By way of illustration, a number of common food products are
presented below with an estimate of their embedded water for a given
weight or volume.
Estimates of water embedded in different products
| Portion |
Litres |
Portion |
Litres |
Portion |
Litres |
| Pint of beer, 568ml |
170 |
Cup of coffee, 125ml |
140 |
Glass of orange juice, 200ml |
170 |
| Glass of milk, 200ml |
200 |
Cup of instant coffee, 125ml |
80 |
Glass of apple juice, 200ml |
190 |
| Cup of tea, 250ml |
35 |
Glass of wine, 125ml |
120 |
Orange, 100g |
50 |
| Slice of bread, 30g |
135 |
Bread with cheese, 30g + 10g |
90 |
Bag of potato crisps, 200g |
185 |
| Egg, 40g |
135 |
Tomato, 70g |
13 |
Hamburger, 150g |
2400 |
| Potato, 100g |
25 |
Apple, 100g |
70 |
Bovine leather shoes |
8000 |
| Sheet of A4, 80 g/m² |
10 |
Cotton tee-shirt, medium 500g |
4100 |
Microchip, 2g |
32 |
Source: Waterwise
It is clear that different types of food require different amounts
of water to produce them and so embedded water differs greatly by
category. It is important to understand how these figures have been
calculated. The hamburger is taken as the example. Example of embedded water in beef production

Source: Waterwise
Again, while the actual figures may be challenged water is clearly
required in producing cattle feed (grain and roughage in this case),
providing drinking water for cattle and in other services during
production and processing.
The water embedded in products is a growing area of awareness. In
the UK the Food Industry Sustainability Strategy Champions’ Group on
water concludes that “Both retailers and manufacturers should have
regard to the ‘embedded water’ in the products they source, the
associated carbon, and the potential environmental impact these factors
may have, particularly on the products’ countries of origin”. And from GDRC
- Water Footprint
A water footprint is quite simply the volume of water used. At the
individual level, this is expressed in litres. But at the national
level, this becomes complex - The water footprint of a nation is equal
to the use of domestic water resources, minus the virtual water export
flows, plus the virtual water import flows.
The total ‘water footprint’ of a nation is a useful indicator of a
nation’s call on the global water resources. The water footprint of a
nation is related to dietary habits of people. High consumption of meat
brings along a large water footprint. Also the more food originates
from irrigated land, the larger is the water footprint. Finally,
nations in warm climate zones have relatively high water consumption
for their domestic food production resulting in a larger water
footprint. At an individual level, it is useful to show the footprint
as a function of food diet and consumption patterns.
Ten litres of orange
juice needs a litre of diesel fuel for processing and transport, and
220 litres of water for irrigaton and washing the fruit. The water may
be a renewable resource, but the fuel is not only irreplaceable but is
a pollutant, too.
Behind that morning cup of coffee is 140 litres of water used to grow, produce, package and ship the beans.
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1 cup of coffee needs 140 litres of water.
1 litre of milk needs 800 litres of water.
1 kg of wheat needs 1100 litres of water.
1 kg of rice needs 2300 litres of water.
1 kg maize needs 900 litres of water.
- The production of one kilogram of beef requires 22 thousand litres of water.
- To produce one cup of coffee we need 140 litres of water.
- The
water footprint of China is about 775 cubic meter per year per capita.
Only about 3% of the Chinese water footprint falls outside China.
- Japan
with a footprint of 1100 cubic meter per year per capita, has about 60%
of its total water footprint outside the borders of the country.
- The USA water footprint is 2600 cubic meter per year per capita.
Source: UNESCO-IHE - Water Footprint
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- Virtual Water
Virtual water is the amount of water that is embedded in food or other
products needed for its production. Trade in virtual water allows water
scarce countries to import high water consuming products while
exporting low water consuming products and in this way making water
available for other purposes [World Water Council].
For example, the virtual water content (in m3/ton) for potatoes is 160. Others examples - maize=450; milk=900;
wheat=1200;
soybean=2300;
rice=2700;
poultry=2800;
eggs=4700;
cheese=5300;
pork=5900; and beef=16000.
Showing people the ‘virtual water’ content of various consumption goods will increase the water awareness of people.
People
consume water not only when they drink it or take a shower. In 1993,
Professor John Allan (2008 Stockholm Water Prize Laureate), strikingly
demonstrated this by introducing the "virtual water" concept, which
measures how water is embedded in the production and trade of food and
consumer products.
Behind that morning cup of coffee are 140 litres of water used to grow,
produce, package and ship the beans. That is roughly the same amount of
water used by an average person daily in England for drinking and
household needs. The ubiquitous hamburger needs an estimated 2,400
litres of water. Per capita, Americans consume around 6,800 litres of
virtual water every day, over triple that of a Chinese person.
Virtual water has major impacts on global trade policy and
research, especially in water-scarce regions, and has redefined
discourse in water policy and management. By explaining how and why
nations such as the US, Argentina and Brazil 'export' billions of
litres of water each year, while others like Japan, Egypt and Italy
'import' billions, the virtual water concept has opened the door to
more productive water use.
National, regional and global water and food security, for example, can
be enhanced when water intensive commodities are traded from places
where they are economically viable to produce to places where they are
not. While studying water scarcity in the Middle East, Professor Allan
developed the theory of using virtual water import, via food, as an
alternative water "source" to reduce pressure on the scarcely available
domestic water resources there and in other water-short regions. [SIWI
- www.siwi.org]
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