1

Water in Bread

Draft version

January 2016

Water Feasibility Project for

Local Nexus Network of Food, Energy and Water

Kourosh Behzadian, Raziyeh Farmani, David Butler Centre for Water Systems, University of Exeter

Abstract

This report presents a detailed description of water used in bread production with a particular focus

on the perspective of localised food manufacturing. The report is divided into the following principal

sections. Water footprint of wheat-based production including bread is first analysed and their

values are presented and comparisons are made between values in the world and the UK in different

scales including both case studies (Oxfordshire and Cambridgeshire). Wheat production and

associated water demand is then compared in different scales along with its distribution in the UK.

Water used in bread manufacturing is analysed in two sections of milling and bread making

processes. Other aspects of water in bread manufacturing including water quality, environmental

impacts and nexus between water and energy in bread making are also discussed. Then, potentials

and opportunities for conservation of water use in localised bread manufacturing along with its

impact on energy footprint and other environmental categories are identified and discussed.

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Introduction Water is considered as an inseparable component for all types of food production especially in

different steps of bread basket. There are three main steps for producing wheat bread including 1)

agriculture i.e. wheat cultivation, 2) flour milling and 3) bread making. Water is a raw material which

is necessary for all these steps especially for wheat cultivation. On the other hand, water supply for

different purposes (e.g. agriculture, industry and domestic) is becoming a serious issue in most part

of the world in this century. If there is a real stress on water resources and limited water needs

cannot be allocated for all users, the sequence of priority water uses for the above purposes in most

of the countries are domestic, industry and agriculture1. In addition, supplying clean water is going

to be under serious stress in large areas in the UK especially centre, south east and east as shown in

Fig 1 for three time periods in England and Wales. The plausible reasons for the increased water

stress will be likely due to increased water demands as a result of population growth and climate

change. As water priority for industry and agriculture are low, they are more vulnerable and hence

planning and developing appropriate strategies for water conservation are becoming a primary need

for these sectors. Bread production which includes both agriculture and industry should inevitably

consider this into account for both new development and existing businesses.

This report presents water used in different steps of bread production from wheat growing to bread

making in bakeries and in particularly focuses on the case studies. The report has a particular

attention on identifying the key factors on water footprint and water demand of bread production.

The report also investigates opportunities for improvement of water use and particularly explores its

nexus with energy use and how this nexus can be developed and effectively improved in localised

bread production. This report only focuses on water sides of bread production and, when necessary,

water-energy nexus. This report will be part of the LNN (local network nexus) project2 deliverable

which is called water feasibility report. This report has been prepared with respect to two

complementary bread reports (i.e. “Bread” by the University of Oxford and “Energy in Bread” by the

University of Surry) in the LNN project. Readers are also recommended to read those reports for

further studies.

1 OECD (2015), Water Resources Allocation: Sharing Risks and Opportunities, OECD studies on Water, OECD

publishing, Paris, 2 http://localnexus.org/about-the-local-nexus-network/

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Fig. 1 Projection of environmental Agency about deteriorating conditions for water stress areas in

the three periods of baseline, 2020s and 2050s1

Water footprint

The water footprint was introduced in 2002 by Arjen Hoekstra2 as an alternative indicator water use.

Water footprint concept involves quantifying the potential environmental impacts related to water

and offers a useful method to identify where and how risks related to water availability might arise

in the chain of production and import. The water footprint concept is one of the three larger

dimensions of footprint indicators (i.e. carbon footprint, ecological/land footprint and water

footprint). Management of water footprint in food production can have an impact on sustainable

food production and influence public policy between the nations as recognised by European

Commission3 and UNEP4. Therefore, analysis of concurrent impacts of the nexus between water,

carbon and land footprints on each other is crucial when considering various intervention options or

1 http://www.ukrma.org/wp-content/uploads/2015/01/Guide-2-Rainwater-Harvesting.pdf

2 Hoekstra, A.Y. (2003) (ed) Virtual water trade: Proceedings of the International Expert Meeting on Virtual

Water Trade, IHE Delft, the Netherlands 3 European Resource Efficiency Platform. (2012). Manifesto and Policy Recommendations

4 IISD. (2014). Sustainable Consumption and Production (SCP): Targets and Indicators and the SDGs

4

configurations (e.g. as demonstrated in the LNN project changing from centralised to localised food

production). In fact, integration of water footprint with carbon footprint and life cycle analysis can

be considered as effective tools for identifying bottlenecks of the environmental impacts in food

production especially the implications of localised food production and therefore improving their

effectiveness.

The water foot print is closely related to the notion of virtual water trade, introduced by John Allan1,

which refers to the idea that countries can save domestic water by importing food. Water footprint

is beyond the idea of the water volume and is a multidimensional indicator which make explicit the

type of water use (e.g. evaporation or rainwater, surface water or groundwater, or pollution of

water) and the location and timing of water use2. The idea of international trade of virtual water

suggests that the countries (especially arid and semi-arid ones) can save their water resources for

domestic and industrial consumptions by importing water-intensive products (especially agricultural

ones) from the counties with more abundant water supplies3. This trade however cause the

countries with water abundant to lose virtual water when exporting crops and livestock products4.

Some researchers suggest the main difference of virtual water and water footprint is the different

views at how water is used for production or consumption. More specifically, while virtual water

deals with water volumes used in production only, water footprints explore the volumes of water

used from both viewpoints of production and consumption5. For example, the virtual water of wheat

incorporates the total of rainfall and irrigation water consumed to produce crop. However, the

water footprint of a wheat consumer includes the water used required to produce wheat, process

wheat into bread, transport, distribute final products and other supply chain. In other words, water

footprint can be viewed from both side of water footprint of production and water footprint of

consumption6. Furthermore, water footprint of a product as an empirical indicator is the sum of the

water consumed to produce a product/commodity over the entire steps of the supply chain of a

product. For example, the water footprint of wheat is the water used for growing wheat that is no

longer actually contained in the wheat but it is virtual water used at the place where the product

was actually produced.

Table 1 compares the average amounts of water footprint for various wheat-based products and for

the world, UK and two case studies (i.e. Oxfordshire and Cambridgeshire). More importantly, the

global average of water footprint for wheat bread is 1608 m3/tonne. The water footprint of a

product may be highly variable in different countries depending on climate conditions and

agricultural practice. This is especially true with agriculture with the climate directly acting on

1 "Looming water crisis simply a management problem" by Jonathan Chenoweth, New Scientist 28 Aug., 2008,

pp. 28-32. 2 http://waterfootprint.org/en/water-footprint/frequently-asked-questions/#CP1

3 Wichelns, D. (2011). Do the virtual water and water footprint perspectives enhance policy discussions?.

International Journal of Water Resources Development, 27(4), 633-645. 4 Chapagain, A. K., Hoekstra, A. Y. & Savenije, H. H. G. (2006) Water saving through international trade of

agricultural products, Hydrology and Earth System Science, 10(3), pp. 455–468 5 Vela´zquez, E., Madrid, C. & Beltra´n, M. J. (2009) Rethinking the concepts of virtual water and water

footprint in relation to the production–consumption binomial and the water–energy nexus, Water Resources Management, 25(2), pp. 743–761. 6 Vanham, D., & Bidoglio, G. (2013). A review on the indicator water footprint for the EU28. Ecological

Indicators, 26, 61-75.

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evapotranspiration. A good commercial value for the global average yield of grain under irrigation

scheme is 6 to 9 tonne/ha. As such, the water utilization efficiency for harvested yield of grain varies

then between 0.8 and 1.6 kg/m3 1. As such, the water footprint for growing wheat is between 625

and 1250 m3/tonne.

Table 1 water footprint (m3/ tonne) of product for various wheat-based products2

Product World UK Oxfordshire Cambridgeshire

Duram wheat 1826 593 596 574

Wheat or meslin flour 1849 600 602 581

Wheat bread 1608 522 524 505

Dry pasta 1849 600 602 581

Wheat groats and

meal

2036 661 664 639

Wheat pellets 2036 661 664 639

Wheat starch 1436 466 468 451

Wheat gluten

(whether or not dried)

4189 1358 1365 1316

More specifically, wheat yield in the UK is amongst the highest in the world (i.e. an average of 6.2

tonne/ha compared to the global average of 2.2 tonne/ha over the period of past 50 years3). Thus,

the water footprint for producing wheat bread in the UK substantially reduces to a total of 522 m3

water per tonne of bread based on the data collected between 1996 and 20054. Oxfordshire has

almost similar water footprint for all of the wheat-based products especially for wheat bread (524

m3/tonne) while water footprint of wheat bread in Cambridgeshire is fairly lower than UK average

1 http://www.fao.org/nr/water/cropinfo_wheat.html

2 Mekonnen, M. M., & Hoekstra, A. Y. (2010). The green, blue and grey water footprint of crops and derived

crop products, Volume 2: Appendices, Research Report Series No 47, UNESCO-IHE Institute for Water Education 3 FAOSTAT 2015, Food And Agriculture Organization Of The United Nations Statistics Division,

http://faostat3.fao.org/home/E 4 Mekonnen, M. M., & Hoekstra, A. Y. (2010). The green, blue and grey water footprint of crops and derived

crop products, Volume 2: Appendices, Research Report Series No 47, UNESCO-IHE Institute for Water Education

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(505 m3/tonne). Also, note that over 95% of lifecycle water of wheat bread in the UK is used in

agriculture for growing wheat1.

How to calculate water footprint

There are two main approaches for calculating water footprint of a product2: (1) volumetric

approach using water footprint network (WFN)3 approach; (2) life cycle analysis in which a weighted

water footprint approach is used. As most of the existing water footprint studies follow the first

approach, it is briefly described here. Essentially, calculation of water footprint incorporates three

categories of blue, green and grey water. Blue water footprint refers to the volume of surface water

(e.g. lake, river and etc.) and groundwater consumed. Domestic and irrigation water are examples of

blue water footprint. The green water footprint refers to the rainwater and natural soil moisture

consumed. Green water is more renewable than blue water. Grey water footprint refers to the

volume of freshwater that is required to assimilate the load of pollutants based on existing ambient

water quality standards. In fact, grey water footprint is the volume of clean water required for

diluting polluted water resulted from agricultural, industrial and domestic usages. Calculation of

water footprint of a product takes into account the water that is abstracted from a water catchment

and does not return to the same water catchment or is altered (polluted). This abstracted water is

considered in the water footprint when it is used in different ways such as evaporation, incorporated

in the product, discharge to the sea or another water catchment or even the same water catchment

but at a different time period. Also note that as blue water abstraction usually requires energy (e.g.

from wells, river or other surface water resources), the products with high rate of blue water have

more energy/carbon footprint compared to those with high percentage of green water. In other

words, changing the crop or geographical position of a crop to attain a product with high rate of

green water would be highly beneficial to reducing energy footprint.

Table 2 compares the share of these water footprint categories in wheat bread production between

the global average, UK and both case studies (see also Table A.1 for details of water footprint

categories for wheat-based products). As it can be seen, the global share of bread water footprint is

70% for green water, 19% for blue water and 11% for grey water. Due to the climate in the UK

including Oxfordshire and Cambridgeshire, wheat is not irrigated (i.e. uses no blue water) and is a

rain-fed crop over the length of growing period4. This can be recognised as an advantage with

respect to energy footprint when compared to the shares of the categories in the global average of

water footprint. In addition, the sum of the three categories of water footprint for the global

1 WRAP (2013) ‘Hotspots, opportunities & initiatives: Bread & rolls’, see

http://www.wrap.org.uk/sites/files/wrap/Bread%20&%20rolls%20v1.pdf 2 Vanham, D., & Bidoglio, G. (2013). A review on the indicator water footprint for the EU28. Ecological

Indicators, 26, 61-75. 3 Hoekstra, A.Y., Chapagain, A.K., Aldaya, M.M., Mekonnen, M.M., 2011. The Water Footprint Assessment

Manual: Setting the Global Standard. Earthscan, London, UK. 4 Mekonnen, M. M., & Hoekstra, A. Y. (2010). The green, blue and grey water footprint of crops and derived

crop products, Volume 2: Appendices, Research Report Series No 47, UNESCO-IHE Institute for Water Education

7

average is similar in either irrigated or rain-fed agricultural lands per tonne of the product1. In

Oxfordshire for example, the share of these categories is made up of 385 m3 (74%) green water and

139 m3 (26%) grey water. This reduced water footprint compared to the global average value can be

attributed to some factors such as increased fertilisers as well as reduced water demand of growing

wheat during irrigation in Oxford and Cambridge areas, which is directly linked to climate

parameters such as temperature, humidity, sunshine and wind speed. This considerable reduced

water footprint (around one third of global average) can be taken as an advantage for local bread

production in Oxford and Cambridge in which no surface water resources would be required for

growing wheat and the required water can be supplied through only rainfall.

Table 2 Three categories of water footprint (m3/ tonne) of product for wheat bread

Green water

footprint

Blue water

footprint

Grey water

footprint

Total water

footprint

World 1124 301 183 1608

UK 380 0 142 522

Oxfordshire 385 0 139 524

Cambridgeshire 374 0 131 505

Out of the total crop water consumption in the EU, the share of green water is 93% and blue water is

7% while these rates in the worldwide scale are 86% for green water and 14% for blue water2. In this

statistic, Wheat is accounted for the crop with the most green water consumption in the EU with an

average of 103 km3 and production of 131 Mt per year. As such, the water footprint of wheat is 928

m3/tonne in the EU which is considerably lower than the average global water footprint of wheat

(1826 m3/tonne). Even, water footprint of wheat is variable between the EU countries. Generally,

water footprint of wheat is lower in western and northern Europe (e.g. Denmark 788 m3/tonne and

UK 607 m3/tonne) than southern and eastern Europe (e.g. Spain 1476 m3/tonne and Romania 1779

m3/tonne).

Wheat growth

Wheat growth is one of the three top agricultural products (i.e. maize, rice and wheat) that is grown

almost all over the world. Based on FAO statics in 2012, the world production of wheat is about

1 Mekonnen, M. M., & Hoekstra, A. Y. (2010). The green, blue and grey water footprint of crops and derived

crop products, Volume 1: Appendices, Research Report Series No 47, UNESCO-IHE Institute for Water Education 2 Vanham, D., & Bidoglio, G. (2013). A review on the indicator water footprint for the EU28. Ecological

Indicators, 26, 61-75.

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670.9 million tonnes from 215.5 million ha with the average yield of 3.11 tonnes/ha1. Among this

amount of production, the biggest wheat producer in the world is China followed by USA, India, USA,

Russia, France, Canada, as the top six counties by wheat production as shown in Fig. 2 as percentage

wheat production in 2014 and average between 1961 and 2014. As it can be seen, the share of

global wheat production in the UK is only slightly over 2%. However, wheat yield in the UK is

considerably higher than those in the top six counties, the EU and global average in both year 2014

and average wheat production over the past 50 years between 1961 and 2014 (see Figs. 3-5). More

specifically, the overall wheat yield in the UK is greater than the global average as much as 2.5 times

up to 3 times over this period. Also, the UK is self-sufficient in supplying national wheat and flour

demands. In the UK, the area of winter wheat planted for harvest in 2015 is expected to fall slightly

to 1.80 million hectares. Approximately 40% of this area is varieties with bread or biscuit making

potential (nabim Groups 1 – 3) 2. Note that for bread making, Group 1 varieties are preferred since

they contain high levels of appropriate quality proteins (13%). It is difficult to predict national

production but the 5-year average yield of 7.9 tonne/ha would produce a wheat crop of 14.2 million

tonnes in the UK3.

Fig. 2 % of production for top wheat producing countries in the world

1 "World Wheat, Corn and Rice". Oklahoma State University, FAO Stat. Archived from the original on [Access on

10 Dec 2015] 2 UK Flour Milling Industry 2015 http://www.nabim.org.uk

3 UK Flour Milling Industry 2015 http://www.nabim.org.uk

2.1

4.65.5

9.09.8

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7.6

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12

14

16

18

20

UK Canada France Russia India USA China

Perc

enta

ge o

f w

hea

t p

rod

uct

ion

(%)

Average 2014

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Fig. 3 Wheat yield for top wheat producing countries and global average

Fig. 4 Variation of wheat yield over the last 50 years in the UK, Europe and World1

1 http://faostat3.fao.org/home/E

8.6

3.1

7.4

2.53.0 2.9

5.0

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UK Canada France Russia India USA China World

Wh

eat

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d (

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0

2

4

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1961 1971 1981 1991 2001 2011

Wh

eat

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d (

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Year

United Kingdom World Europe

0

100

200

300

400

500

600

700

800

1961 1971 1981 1991 2001 2011

Wh

eat

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1961 1971 1981 1991 2001 2011

Wh

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Fig. 5 Comparison of variations of wheat production and area harvested for growing wheat between

the UK, EU and the World over the past 50 years1

The spread of arable lands of growing wheat (Fig. 6) shows that growing wheat in Oxford and

Cambridge (located in northwest of London, southwest and east regions) has a lot of potential for

intensive wheat growth. According to Defra data in 2013, the total area being grown for wheat were

42,822 ha in Oxfordshire and 91,984 ha in Cambridgeshire2.

Fig. 6 spread of arable lands for growing wheat in England in 2010

1 http://faostat3.fao.org/home/E

2 Bread Report, LNN project, Oxford University, November 2015

0

50

100

150

200

250

300

1961 1971 1981 1991 2001 2011

Are

a h

arve

sted

(mill

ion

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Year

World Europe

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0.5

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1.5

2.0

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1961 1971 1981 1991 2001 2011

Are

a h

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Year

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The variation of wheat yields across the regions in England is also shown in Fig. 71. Oxfordshire and

Cambridgeshire account for high yield region in the UK with a yield of around 9 tonne/ha. As wheat

sowing is conducted during winter in the UK, yields are aided by the favourable conditions

throughout the spring and summer.

Fig. 7 Wheat yield by England region

Bread manufacturing

Bread manufacturing is generally divided into two parts: milling process and bread baking. During

the milling process, water is added to soften the wheat, making it easier to process. Based on the

information collected in the interviews from two mills in Oxfordshire, the amount of water used

within the process is approximately 1% of total wheat by weight. For baking bread, water is

combined with flour to form a dough and accounts for the second most important ingredient by

weight (i.e. around 36%) after flour as the main ingredient. While water is the second most

important ingredient of bread making process, the total water used in baking bread is insignificant

compared to the amount used for growing wheat.

Harvested wheat is transported to a mill for producing flour before sending to bakeries. Most of

typical flour and bread types produced in the UK are entirely from UK grown wheat. Hence, the UK is

self-sufficient in flour and UK wheat used for milling will be almost 80% in 2015 although it used to

be up to 87% several years ago. The remaining flour is imported from Germany, Canada, France and

USA due to different qualities used for producing stronger flours especially high protein and specific

baked production. According to the nabim database, there are currently 30 nabim member

companies operating 50 flour mills located throughout England, Wales, Scotland and Ireland in

which two mills are located in Oxfordshire and one in Cambridgeshire. Many smaller millers have

developed niches ranging from retail flour mixes to flours for specific uses such as flours for

speciality or ethnic breads. As a result of advances in technology and the skill of the miller, the

industry produces more than 400 different types of flour2.

1 Farming Statistics Final crop areas, yields, livestock populations and agricultural workforce At June 2015 -

United Kingdom at https://www.gov.uk/government/collections/structure-of-the-agricultural-industry#2015-publications 2 UK Flour Milling Industry 2015 http://www.nabim.org.uk

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Fig. 8 Distribution of mills in the UK and Ireland1

Water is one of the primary requirements in bakery product manufacturing. The water used in this

industry varies depending on the end product across different baking products, processes and

equipment as well as domestic uses such as washing the site and rinsing/cleaning equipment.

According to the study of National Business Water Efficiency Benchmarking (NBweb) in Australia,

water use benchmarks of bakery product manufacturing range between 0.43 and 16.97 m3/tonne

with an average of 5.323 m3/tonne of bread produced2. The information of these benchmark values

are collected from different bakery products including bread, cake, pastry and biscuit manufacturing.

The highly variable range can be attributable to some influencing factors such as size of bakery, type

of end products and technologies and equipment for water consumption. Furthermore, some

localised bakeries have some other food activities and for example serve similar to cafes and small

restaurant (e.g. Cornfield bakery visited in Oxfordshire) and thus use a lot of water for the purposes

other than bread making and so their water consumption per tonne of bread will be high.

Given that finished bread product (loaf) has 12% reduction in weight during baking/cooling

processes3, each tonne of bread requires 1.136 tonnes of dough. Assuming water content in the

dough is 36.1% of the total weight4, water required for this amount of dough is 0.41 m3/tonne of

bread. Comparing this water use with the benchmark values shows that the rest of water

consumption (i.e. ranging from 0.03 m3/tonne to 16.56 m3/tonne with an average of 4.82

m3/tonne) are used for other usages (e.g. rinsing, washing, cleaning and hygienic purposes). This

1 Nabim Wheat Guide 2015 http://www.nabim.org.uk

2 http://www.nbweb.com.au/Useful-resources/Factsheets.aspx

3 http://www.thefreshloaf.com/node/4140/one-pound-loaf-flour-weight-or-dough-weight;

4 Oxford University, Bread report, LNN research project, internal report, November 2015

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value can be either quite high representing inefficient use of water in bakery or reasonable/low

showing operating targets of water use have been obtained in bakery. The benefit of comparing real

water use in a bakery with benchmark values shows how water is efficiently consumed in the site

and potentials for reducing water and thus saving money can be further investigated by bakery

manufacturers. United Utilities as a water company in the UK, considers 12% domestic sewerage

return in the water supplied to National bakeries in the North West of England1. Given 5% water loss

in domestic consumption, the share of domestic water use in bakery is 12.6% although the detailed

analysis of a research in the bakeries in Northwest of England shows that domestic water use

accounts for 7.3% of total water use in bakery2. The share of this percentage for domestic waster

use are 2.3% for tap outlets, 2.57% for WC flushing, 1.75% for urinal flushing and 0.7% for

showering.

Role of water in baking bread

Water is one of the primary materials (i.e. flour, water, salt and yeast) in bread baking. More

specifically, among the primary and primary materials in most of the recipes for baking bread, water

is the second ingredient with around 60% of flour compared to other ingredients such as fat and salt

and yeast with around 3, 2 and 1% of flour by weight3. The percentage of added water can be higher

or lower depending on the type of flour-made products (e.g. around 100% of flour for pikelets or

30% of flour for pie pasty or sweet biscuits). Water is an essential requirement for yeast metabolism

in the dough because yeast and enzymes can only work when dispersed in water and yeast can only

absorb food which is in solution. When a dough is mixed some of the water (around 6%) is absorbed

by the flour proteins and some by the starch. The rest of free water forms the water phase of the

dough. In the water phase, the yeast cells are dispersed and soluble products such as salt, sugar,

soluble proteins are dissolved. Water has also impact on the stiffness (harshness) of the dough plus

the fermentation speed. Maximum possible use of water can reduce the price of raw materials and

make doughs to be processed effectively by softening the dough and increasing fermentation speed.

In stiff dough there is little free water so the carbon dioxide gas production by yeast is slow. In a

weak dough there is too much free water and therefore too little binding between the dough

constituents and a too fast fermentation process and the carbon dioxide production is fast. A lot of

water (weak dough) will give an increased enzyme activity. Less water will reduce the enzyme

activity. The dough temperature and hence fermentation process can also be adjusted by changing

the water temperature.

The correct amount of water used in a dough is important to ensure the correct consistency and

plasticity of the dough and withstand moulding and form easily to the desired shape. In order to

reduce water evaporation, fat is added to soften the dough during dough processing. The amount of

fat is dependent on the type of bread but if the level of fat in a dough increases, the dough water

level is decreased to counteract the dough softening effect of the fat. Water content in the dough

1 http://www.watermanagementsolutions.co.uk/wp-content/themes/water_management_solution/national-

bakeries.pdf, Water and Effluent Survey Report, National Bakeries, North West, England 2 http://www.watermanagementsolutions.co.uk/wp-content/themes/water_management_solution/national-

bakeries.pdf 3 http://www.bakersassist.nl/rawmaterials.htm

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within specific limits has also impact on the softness of the finished bread. For example, adding more

water to a dough would result in a softer bread plus more loaves out of the same amount of flour.

The specific limits of water content in a particular dough also depends on other factors such as flour

quality, bread type and shape, bread making process, processing equipment.

During baking and cooling, the main weight loss usually occurs mainly due to the evaporation of

water1. Energy in the oven/cook is required to first heat the dough and then evaporate the water.

The energy required for these steps are calculated based on the difference of the average

temperature of the dough (around 40 ⁰C) and internal temperature of the bread (around 95 ⁰C). The

water loss is typically around 50g for producing an 800g loaf of bread. The bread is then cooled for

approximately two hours with the temperature maintained around 20 ⁰C and the humidity of 85-

90%. The air circulation fans in the cooling process use the main part of energy to maintain humidity

levels by injecting water into the air stream where necessary. If the bread is not sufficiently cooled,

the water content is not evaporated enough and condensed on the inside of the packaging and the

bread will collapse when sliding.

Water quality

Water quality is very important in bread making processes and water used must be controlled for

organic, inorganic impurities and bacterial content. Residual chlorine which is injected to disinfect

clean water supply needs to be rigorously analysed and controlled to ensure it is within standard

limits. Other water contaminants are known to adversely impact the processes in bakeries. The

water used during all stages of bread manufacturing (i.e. milling and baking processes) intended for

human consumption needs to be as high quality as drinking water. Due to these requirements, both

milling and baking companies interviewed in the Oxford area reported they use mains water to

supply the necessary water for their processes. This is because mains water is easily accessible and

drinking water quality is regularly tested and rigorously checked by the UK water companies and

Drinking Water Inspectorate to ensure drinking water standards are met2. In addition, water charge

is approximately around £2.5/m3 in Oxfordshire3 and £3.5/m3 in Cambridgeshire4 considering fixed

charges. It can be argued that this relatively cheap price of clean water and thus water bills as well as

acceptable quality of water might be the main reasons that bakeries and mills prefer to use mains

water compared to other alternative water resources.

However, if raw water for bread making is going to be supplied from other sources (e.g.

groundwater), water needs to be treated before it can be used for processes. Part of the water used

for different purposes in bread making factory may become wastewater. Typical types of

wastewater generated are wastewater from domestic water use (typically 5-10% water loss due to

evaporation, garden watering and etc.) and wastewater from washing floor, equipment, trays and

pans. Bakery manufacturing is usually charged for returning both domestic water use and food

1 Industrial Energy Efficiency Accelerator Guide to the industrial bakery sector, CARBON TRUST, 2008

2 DWI 2015, Drinking water quality in England: the position after 25 years of regulation, Chief Inspector of

Drinking Water Report 3https://www.thameswater.co.uk/tw/common/downloads/literature-water-waste-water-

charges/Our_Charges_2015-16_(web).pdf 4 http://www.cambridge-water.co.uk/customers/metered

15

processing water to sewer systems. The return of wastewater from the food processes is known by

water companies as “trade effluent return” which is around 20% of the metered water usage. Some

water companies require treatment of trade effluent from food manufacturing before discharging to

sewer systems or receiving water bodies. This might be an expensive process and needs some

appropriate measures to avoid or minimise this process in food manufacturing.

Water availability

Water abstraction in England and Wales is granted by the Environment Agency (EA) based on an

abstraction licensing system for a term duration of 12 years, which is linked to cyclical reviews of

water availability in a catchment with the expectation of periodic renewal. Based on regulation set

out by the EA, water abstraction of more than 20 m3/day by a business from either a surface or an

underground source needs an abstraction licence (although some cases such as trickle irrigation are

exempt)1. The availability of water resources for abstraction is assessed by the EA through the

Catchment Abstraction Management Strategy (CAMS) approach. The EA uses CAMS based on 16

different mapped groundwater catchment areas in the UK for water abstraction licencing. Most

areas in Oxfordshire are grouped in the three catchments of West Thames map area2 including 1-

Cherwell, Thame and Wye catchment (i.e. Oxford city and the northern and eastern parts of the

county), 2- Kennet and Vale of White Horse Catchment (i.e. southern parts of the county) and 3-

Cotswolds Catchment (i.e. western part of the county). These areas are predominately rural and

semi-rural, grassland and the remainder woodland and small urban areas. These lands are used

extensively for agriculture such as arable farming and grazing. For most of the areas in this case

study, the Environment Agency will grant an abstraction licence only during periods of high flow.

Consumptive groundwater licences, which do not have a direct and immediate impact on river flow,

may be permitted all year, providing the level of resource use allows it, but may have restrictions

such as prescribed groundwater level. Further details of water availability in both case studies can be

found in the “Water in Tomato Report”3.

Based on the interviews with local milling and bakery businesses in Oxfordshire, the water they use

in manufacturing is supplied via mains water at present, and consequently it has energy embedded

in it as a result of this water being abstracted, transported, stored, treated and distributed to their

premises by the water company (Thames Water). As their water demand is less than the threshold

of 20 m3/day, an abstraction licence would not be required if these businesses decided to opt for

direct abstraction from a local surface or groundwater source. However, locally sourced water (as

distinct to mains drinking-quality water) would need to be pumped, stored and treated before being

used in milling and baking. These steps are energy demanding which needs further analyses in

relation to water and energy nexus issues.

1 Environmental Agency (2014a). Water management: abstract or impound, Environmental management –

guidance, https://www.gov.uk/guidance/water-management-abstract-or-impound-water 2 Environmental Agency (2014b). Abstraction licensing strategies (CAMS process), Environmental management

– collection, https://www.gov.uk/government/collections/water-abstraction-licensing-strategies-cams-process 3 Water in Tomato Report, LNN research project, Internal report, University of Exeter, September 2015.

16

Potentials for water-energy-carbon nexus in localised bread production There are some potentials and opportunities for improvement of water, energy and carbon nexus in

the main steps of bread production especially in the agriculture and bakery parts. For example, once

alternative water sources (e.g. rainwater harvesting or greywater recycling schemes) are used to

replace the existing sources (e.g. mains water) in the localised bread manufacturing, additional

energy is required to collect, abstract and prepare water for reuse. Further details and different

aspects of potential improvements for water and energy nexus are outlined and discussed below.

Historically, water and wind used to have a strong nexus with energy for generating power in water-

driven mills. However, it has now replaced with high technology and automated industry in modern

flour mills to function as continuous-flow operations. For example, if water mills were dependant on

water flows to generate power for milling process (i.e. they are off sometimes due to lack of water

or wind), model flour mills can operate continuously and even large mills operate over 360 days per

year.

The Carbon Trust conducted the IEEA programme in 2008 to explore innovative opportunities for

reduction of carbon emissions from industrial bakery sector as an industry with energy-intensive

operations and major source of carbon emissions1. The Carbon Trust finally developed a list of

innovative opportunities for significant reduction of carbon emissions. During the bread baking,

there are some potentials for reducing energy which are related to baking and cooling processes in

which water content can have a major role. More specifically, bread will lose around 12% of its

weight (i.e. from 900-930g to 800g for a loaf) predominantly due to the evaporation of water during

the processes of bread baking and cooling. For example, cooling process of bread baking and typical

cooler especially is an energy-consuming part in bread baking. More specifically, air circulation fans

use around 90% of the total energy used in a cooler plant operation2. The main function of the air

circulation fans in the bread cooler is to maintain 1) temperature by controlling the proportion of

fresh and recycled air and 2) humidity levels by injecting water into the air stream. The power

required for a typical bread cooler plant is around 30-60 KW. There are some potential for

improvement the technology of cooler plants in order to reduce energy requirements while

maintaining temperature and humidity levels.

More specifically, Fig. 9 shows the breakdown of the energy/CO2 emissions in the processes of a

typical bread bakery in the UK. The oven step (bread baking) is the most energy-intensive process in

a typical bread bakery (around 40% of total energy). Reduction of baking time is therefore a financial

and environmental benefits. Given that the target bread remains similar moisture levels to existing

bread, a shorter baking time can be achieved by lowering water evaporation by the oven that can be

obtained by reducing water levels in the recipe. Reduction of water content can also be offset by

using warmer dough (higher temperatures) during mixing to achieve the dough as soft as equivalent

high water levels. As a result, 20% reduction (around 6 minutes) in bake time can be achieved in

bread in which the starch was gelatinised and all other textural and structural parameters were

similar to those for the full bake time3. Further energy reductions can be achieved in mixing and

1 Industrial Energy Efficiency Accelerator Guide to the industrial bakery sector, CARBON TRUST, 2008

2 Industrial Energy Efficiency Accelerator Guide to the industrial bakery sector, CARBON TRUST, 2008

3 http://www.campdenbri.co.uk/news/energy-reduction-in-baking.php

17

proofing when using lower water content and warmer dough. All this would result in the reduction

of both energy and water consumptions.

Fig. 9 Breakdown of energy/CO2 emissions from a typical bread bakery site1

Among the processes of a typical bread bakery site (Fig. 9), around 5% of total energy

consumption/CO2 emissions is also used for washing baking trays and plans. Saving in the amount of

washing of trays can lead to reducing energy and CO2 emissions. Using water-efficient appliances

and equipment (e.g. ice and dishwashing machines with energy-efficient standards) can be useful for

this purpose. One successful example of these water saving appliances in local bakeries is the

innovation of a small bakery in Ohio State of the US that reduced its water use by 51% through

replacing its three-compartment sink with a high-temperature warewasher2. Note that the

warewashers which are typically energy and water efficient can provide opportunities for water and

energy saving as well as reducing operating costs and increasing profit. Applying water-efficient

appliances and fittings for domestic water consumptions in the bakery which accounts for around 7-

12% of total water consumption would be beneficial. The result of a research on Northwest of

England bakeries shows this that domestic water use which accounts for 7.3% of total water use can

be reduced by %29 by using water-efficient appliances and fittings3.

1 Industrial Energy Efficiency Accelerator Guide to the industrial bakery sector, CARBON TRUST, 2008

2http://www.sustainablefoodequipment.com/Water-Savings/Learn-Best-Practices/Articles/Water-

Conservation-Starts-in-the-Dishroom/ 3 http://www.watermanagementsolutions.co.uk/wp-content/themes/water_management_solution/national-

bakeries.pdf

18

Water heating accounts for 14% of energy use in bakeries1. There are some potential for heating

water other than mains gas/electricity such as providing energy through renewable energy (e.g.

solar panel energy, geothermal heating and etc.).

Another opportunity for improving water and energy consumption in bakeries is to design new

buildings or retrofit existing ones to meet the LEED, BREEAM, Code of Sustainable Home standards.

LEED (Leadership in Energy and Environmental Design), which is voluntary environmental

certification system by the US Green Building Council for buildings in 20002, refers to sustainable

design in five important areas: site development, water and energy efficiency, material selection and

indoor environment quality. LEED is similar to BREEAM (Building Research Establishment’s

Environmental Assessment Method) in the UK in 19903. BREEAM sets best practice standards for the

environmental performance of buildings through design, specification, construction and operation.

Similarly, BREEAM evaluates projects against nine criteria including water and energy efficiency. The

Code of Sustainable Home is a national standard in the UK and similarly measure and rate the

sustainability of design categories in which water, energy and water run-off are within the main

categories4. Some clients (e.g. public sectors) may require the use of BREEAM or LEED for developing

new local bakeries or retrofitting existing ones.

Rainwater harvesting (RWH) systems can also be suggested as a new alternative water resource. In

addition to water saving in this option, it requires energy and has some environmental impacts

especially GHG emissions/carbon footprint which needs to be analysed concurrently. The research

works show that the RWH systems has around 0.5kWh more energy than mains water per cubic

metre delivered5. This may be realised that the RHW system is an inefficient-energy element in the

bakery manufacturing. This is against the future needs of the water available that makes necessary

building water reuse and recycling due to water shortages. Therefore, improvement of reliability and

resilience of water supply should be recognised and included as performance metrics along with

carbon footprint and other environmental impact categories in the analyses of alternatives.

As outlined above, all opportunities for reducing water consumption in different steps of the bread

products (i.e. wheat growth, milling processes and bread baking) may have some implications and

impact on energy consumption. Therefore, there is strong nexus between water and energy

consumption the food manufacturing and especially here in bread manufacturing which needs to be

seen concurrently when developing strategies for reducing water use or water reuse/ recovery/

recycling.

Opportunities for improvement of water use in local bakery

Improvement of water utilisation in baking processes efficiently not only reduce energy

consumption but it can have impacts on some other factors such as reducing wastewater discharge

1 http://www.bakersjournal.com/business-operations/bakeries-and-energy-2179

2 http://www.usgbc.org/leed

3 http://www.breeam.com

4 http://www.planningportal.gov.uk/uploads/code_for_sust_homes.pdf

5 Parkes, C., Kershaw, H., Hart, J., Sibille, R., & Grant, Z. (2010). Energy and carbon implications of rainwater

harvesting and greywater recycling. Environment Agency, Almondsbury, SC090018.

19

to sewer systems and the costs to bakery manufacturers (e.g. water/energy bills). Also, bakeries use

water for other purposes in addition to water use as the main ingredient of bread and pastry

products. In particular, local and small bakeries (e.g. Cornfield bakery visited in Oxfordshire) are

similar to restaurants and often serve a variety of foods, sandwiches and beverages. Generally,

water consumptions in a bakery shop include: 1) product ingredient; 2) baking processes such as

cooling products; 3) washing equipment, containers, vessels, and the raw food products; 4) cleaning

and sanitizing floors; and 5) other sanitary appliances and fittings (e.g. hand basin, toilet flushing and

shower). Therefore, designing and building equipment in a bakery can particularly consider different

aspects of water saving. Some of these design principles and measures to be taken for reducing

water consumptions in bakeries are suggested below:

Design/provide equipment with minimal or no water use and ease of washing and cleaning

(e.g. use high pressure cleaning equipment).

Install metering equipment for major water appliances and fittings to monitor and control

processes.

Consider alternative water resources (e.g. rainwater harvesting from roofs and groundwater

abstraction) as secondary water consumption in which high quality water may not be

necessary such as hand basin and toilet flushing. Environment Agency in the UK provided an

information guide about how to install a rainwater harvesting system and associated

requirements for non-potable water usages such as toilet flushing, garden watering and

washing machine1. Thames Water which covers Oxfordshire advised that rainwater

harvesting systems must be properly designed and installed in accordance with the

requirements of BS 8515 and the manufacturer’s instructions2.

Consider potential water recovery, recycling and reuse from the baking processes (e.g.

filtration and membrane processes and capturing condensate drain water from air-

conditioning and refrigeration systems) and other consumptions (e.g. grey water recycling

for toilet flushing). For this purpose, special care of water reuse should be taken for heating

systems (e.g. steam boilers and hot-water boilers for providing heat and hot-water,

respectively). For example, closed-loop systems can save both water and energy by

returning and thus reusing water and steam condensate in these systems. Also, water as

heat transfer agent is relatively clean and can be reused for different applications in the

bakery.

Consider leakage reduction in pipe systems and frequent openings of water

temperature/pressure relief valves through regular inspection of plumbing and make

discharge pipes visible and easy to control valve activation and monitor/repair leaks.

Consider water-efficient operation in the bakery activities. For example, dishwashing which

is a water-intensive practice should be used only with full loads to conserve water and

energy. Water treatment of raw water or alternative water sources should only be used

when and if it is necessary due to saving energy of treatment. Also, water-efficient

appliances and fittings (e.g. low-flush toilet, automatic-shutoff taps, water efficient nozzles

1http://webarchive.nationalarchives.gov.uk/20140328084622/http:/cdn.environment-

agency.gov.uk/geho1110bten-e-e.pdf 2https://www.thameswater.co.uk/tw/common/downloads/water%20efficiency/5_steps_to_sustainable_wate

r.pdf

20

on hoses for washing) should be used. Floor cleaning should be done by using low-flow,

high-pressure nozzles and when water is needed.

Consider some priority steps to establish an effective program for water conservation. For

example, it might be a good plan to establish a reward and personal recognition program for

employees who contribute significantly to water conservation. The establishment of work

teams and employee instruction to help conserve water in bakeries has also been shown to

be very successful.

Consider and apply recommendations and initiatives presented by water companies and

NGOs for water conservation. For example, wastewater in the food and beverage industry in

Canada typically accounts for 8% of production costs according to the Alliance of Ontario

Food Processors (AOFP)1. AOFP has developed a resource, available on CD-ROM, called

“Toolbox for Water and Waste Conservation” to help companies develop waste and

wastewater reduction initiatives.

1 http://www.bakersjournal.com/business-operations/bakeries-and-energy-2179

21

Summary and conclusions Water is a primary ingredient for all steps of bread production although water used in agriculture for

wheat cultivation accounts for over 95% of lifecycle water use of bread in the UK. Water footprint

for wheat bread in the UK is 522 m3/tonne which is around 3 times smaller than global average

(1608 m3/tonne) due to high amount of wheat yield in the UK. Oxfordshire has similar wheat bread

(524 m3/tonne) whereas Cambridgeshire has a fairly lower value (505 m3/tonne) of the UK average.

During the milling process, water is added to soften the wheat, making it easier to process. Based on

the information collected from two mills in Oxfordshire, the amount of water used within the

process is approximately 1% of total wheat by weight. For baking bread, water is combined with

flour to form a dough and accounts for the second most important ingredient by weight (i.e. around

36%) after flour as the main ingredient. Approximately 7% of the total water use in bakery is

consumed as domestic water. While water is the second most important ingredient of bread making

process, the total water used in baking bread is insignificant. Due to relatively low water bill in

Oxfordshire (around £2.5/m3) and Cambridgeshire (around £3.5/m3) as well as acceptable quality of

water, it has been selected as the main source of water by bakeries and mills and preferred to other

alternative water sources.

Regardless of small water bills in bread manufacturing compared to energy bills and other costs,

employing water management strategies (e.g. water-efficient appliances and fittings) to reduce

water use has a number of benefits especially for local bakeries. Water saving for domestic water

use in bakeries can be achieved by around 30%. There are some potentials for reducing water use in

the bread making processes (e.g. warewashers). The main benefits of reducing water use in bakeries

are 1) reduction of water use and thus water bill; 2) reduction of sewage discharge and hence sewer

charges because most water companies calculate those charges as a percentage of the metered

water use; 3) energy use and consequent energy bills.

Providing raw water from alternative water sources (e.g. rainwater harvesting and groundwater

abstraction) for replacing some water uses although has some advantages (e.g. financially as water is

free), they have some implications on energy and environmental impact categories. The nexus of

water and energy for different scales of alternative water use/reuse would also be important. In

addition, supplying clean water, locally sourced water (as distinct to mains drinking-quality water),

would need to be pumped, collected and treated before being used. These steps are energy

demanding which needs further analyses for nexus issues and compared with mains water and

associated energy impacts.

When considering only energy and environmental impacts, some water reuse options (e.g. rainwater

harvesting scheme) are more energy-intensive compared to energy required in mains water and

therefore they seem to be inefficient-energy intervention in the bakery manufacturing. However,

taking other performance metrics (e.g. reliability or resilience of water supply) into consideration

may be able to show the advantages of these intervention options in local bakery manufacturing

along with carbon footprint and other environmental impact categories in the analyses of

alternatives.

22

Appendix A- Water footprint data

Table A.1 water footprint categories (m3/ tonne) of product for various wheat-based products

Product World UK Oxfordshire Cambridgeshire

Duram Wheat Green 1277 432 438 426

Blue 342 0 0 0

Grey 207 161 158 148

Wheat or meslin flour Green 1292 437 443 431

Blue 347 0 0 0

Grey 210 163 159 150

Wheat bread Green 1124 380 385 374

Blue 301 0 0 0

Grey 183 142 139 131

Dry pasta Green 1292 437 443 431

Blue 347 0 0 0

Grey 210 163 159 150

Wheat groats and meal Green 1423 481 488 474

Blue 382 0 0 0

Grey 231 180 176 165

Wheat pellets Green 1423 481 488 474

Blue 382 0 0 0

Grey 231 180 176 165

Wheat Starch Green 1004 339 344 334

Blue 269 0 0 0

Grey 163 127 124 117

Wheat gluten (whether or

not dried)

Green 2928 989 1004 975

Blue 785 0 0 1

Grey 476 369 361 340