From Field to Bottle: Water Footprint Estimation …
109
reaching the berries [17], which also has the effect of reducing transpiration. Despite
this, a minimum leaf surface area is required to support grape berry production,
estimated to be between 7 and 14 cm
2 /g of fruit [25]. Water from both rain and
irrigation is also lost to direct evaporation from the soil to the atmosphere. The
combined losses due to transpiration and evaporation are often reported as a combined
Evapotranspiration (ET) value. The majority of the water loss in the vineyard is lost
to ET [27]. Finally, overland losses due to surface runoff can occur during heavy
rains [7]. Given the fact that most vineyards are on relatively flat or terraced ground,
such overland losses are often minimal [25]. In sloping vineyards, the presence of
grass cover reduced runoff rates by as much as 40% [7].
For wineries equipped with an on-site wastewater treatment system, it is sometimes possible to utilize treated effluent as a source of irrigation water, reducing the
burden on surface and groundwater resources. The quality of the treated effluent can,
however, impact soil quality and grape berry yield and quality. These factors must
be taken into account when assessing the volume and location of effluent discharges
[13]. This is discussed in more detail in Sect. 4.4.
Finally, water can be used to dilute full-strength industrial chemicals, such as
pesticides and herbicides, prior to their application in the vineyard. Water aspersion
systems can also be used for frost protection in the spring season. By spraying and
coating buds with water prior to an anticipated frost while temperatures are still above
freezing, the resulting ice layer provides protection to the buds, which can mitigate
frost damage [61].
3.2 Water Usage During Vinification
The water in the grape berry pulp provides the liquid in the grape must needed for
wine production. This differentiates wine from other types of beverages, such as beer
and soft drinks, that require substantial volumes of water as direct ingredients in the
production process, representing up to 70% of the total water use in the bottling plant
[20]. Water is not generally used as an ingredient in the wine-making process unless
dilution of the grape must is needed to reduce high sugar concentrations [59]. While
some jurisdictions, such as Australia, allow the addition of water to grape must under
certain circumstances [5], others, including most of Europe, have banned the practice
[58].
Despite this, large volumes of water are used during vinification for equipment
and facility cleaning and sanitizing. Water use estimates range from approximately 1
L/L of wine to 10 L/L of wine [16, 25]. Larger wineries tend to have lower water use
rates, with values reported by Storm [56] ranging from as low as 4.2 L/L for wineries
with a production capacity of more than 1,000,000 cases per year, to as high as 10.6
L/L of wine for those with a capacity of less than 50,000 cases per year.
Annual wine production volumes can also impact normalized water use values (L
water/L wine produced). A benchmarking study conducted by the Beverage Industry
Environmental Roundtable [6] reviewed water use at 27 wineries over a 3-year period
109
reaching the berries [17], which also has the effect of reducing transpiration. Despite
this, a minimum leaf surface area is required to support grape berry production,
estimated to be between 7 and 14 cm
2 /g of fruit [25]. Water from both rain and
irrigation is also lost to direct evaporation from the soil to the atmosphere. The
combined losses due to transpiration and evaporation are often reported as a combined
Evapotranspiration (ET) value. The majority of the water loss in the vineyard is lost
to ET [27]. Finally, overland losses due to surface runoff can occur during heavy
rains [7]. Given the fact that most vineyards are on relatively flat or terraced ground,
such overland losses are often minimal [25]. In sloping vineyards, the presence of
grass cover reduced runoff rates by as much as 40% [7].
For wineries equipped with an on-site wastewater treatment system, it is sometimes possible to utilize treated effluent as a source of irrigation water, reducing the
burden on surface and groundwater resources. The quality of the treated effluent can,
however, impact soil quality and grape berry yield and quality. These factors must
be taken into account when assessing the volume and location of effluent discharges
[13]. This is discussed in more detail in Sect. 4.4.
Finally, water can be used to dilute full-strength industrial chemicals, such as
pesticides and herbicides, prior to their application in the vineyard. Water aspersion
systems can also be used for frost protection in the spring season. By spraying and
coating buds with water prior to an anticipated frost while temperatures are still above
freezing, the resulting ice layer provides protection to the buds, which can mitigate
frost damage [61].
3.2 Water Usage During Vinification
The water in the grape berry pulp provides the liquid in the grape must needed for
wine production. This differentiates wine from other types of beverages, such as beer
and soft drinks, that require substantial volumes of water as direct ingredients in the
production process, representing up to 70% of the total water use in the bottling plant
[20]. Water is not generally used as an ingredient in the wine-making process unless
dilution of the grape must is needed to reduce high sugar concentrations [59]. While
some jurisdictions, such as Australia, allow the addition of water to grape must under
certain circumstances [5], others, including most of Europe, have banned the practice
[58].
Despite this, large volumes of water are used during vinification for equipment
and facility cleaning and sanitizing. Water use estimates range from approximately 1
L/L of wine to 10 L/L of wine [16, 25]. Larger wineries tend to have lower water use
rates, with values reported by Storm [56] ranging from as low as 4.2 L/L for wineries
with a production capacity of more than 1,000,000 cases per year, to as high as 10.6
L/L of wine for those with a capacity of less than 50,000 cases per year.
Annual wine production volumes can also impact normalized water use values (L
water/L wine produced). A benchmarking study conducted by the Beverage Industry
Environmental Roundtable [6] reviewed water use at 27 wineries over a 3-year period