Biscuit Baking Technology: Processing and Engineering Manual

Biscuit Baking Technology
Introduction
Copyright
Contents
About the author
	Iain Davidson, Director, Baker Pacific Ltd.
	Baker Pacific Ltd.
	Experience in the biscuit industry
Acknowledgements
1 The biscuits, cookies and crackers
	1.1 The biscuits, cookies and crackers
	1.2 Crackers
	1.3 Soda crackers: process for sponge and dough
		1.3.1 Description
		1.3.2 Product specification
		1.3.3 Formulation
		1.3.4 Critical ingredients
		1.3.5 Mixing and fermentation
		1.3.6 Dough forming
		1.3.7 Baking
		1.3.8 Oil spray
		1.3.9 Cracker breaking
	1.4 Cream crackers: process for laminated crackers
		1.4.1 Description
		1.4.2 Product specification
		1.4.3 Recipe
		1.4.4 Dough mixing on a horizontal high-speed mixer
		1.4.5 Preparation of the fat/flour for dusting
		1.4.6 Lamination
		1.4.7 Baking
	1.5 Snack crackers
		1.5.1 Process for snack crackers
		1.5.2 Description
		1.5.3 Product specification
		1.5.4 Formulation
		1.5.5 Critical ingredients
		1.5.6 Mixing
		1.5.7 Standing time
		1.5.8 Forming
		1.5.9 Baking
		1.5.10 Baking band
	1.6 Semi-sweet biscuits
		1.6.1 Process for semi-sweet biscuits
		1.6.2 Description
		1.6.3 Product specification
		1.6.4 Formulation
		1.6.5 Critical ingredients
		1.6.6 Mixing
		1.6.7 Forming
		1.6.8 Baking
		1.6.9 Cooling
	1.7 Process for Golden Maria or Dorada
		1.7.1 Description
		1.7.2 Product specification
		1.7.3 Formulation
		1.7.4 Mixing
		1.7.5 Dough forming
		1.7.6 Baking
	1.8 Short doughs: rotary moulded biscuits
		1.8.1 Process for moulded short dough biscuits
		1.8.2 Description
		1.8.3 Product specification
		1.8.4 Formulation
		1.8.5 Critical ingredients
		1.8.6 Mixing
		1.8.7 Standing time
		1.8.8 Rotary moulding
		1.8.9 Baking
		1.8.10 Cooling
		1.8.11 Process for ginger biscuits
		1.8.12 Description
		1.8.13 Product specification
		1.8.14 Formulation
		1.8.15 Process for ginger crunch biscuits
	1.9 Cookies
	1.10 Process for a chocolate chip cookie
		1.10.1 Description
		1.10.2 Product specification
		1.10.3 Formulation
		1.10.4 Mixing
		1.10.5 Forming
		1.10.6 Baking
		1.10.7 Cooling
	1.11 Sandwich biscuits
		1.11.1 Description
		1.11.2 Recipes for creams
		1.11.3 Process for sandwich production
	1.12 Long shelf life cakes, snack cakes
		1.12.1 Process for Jaffa cakes
		1.12.2 Product specification
		1.12.3 Mixing
		1.12.4 Baking
		1.12.5 Cooling and jam depositing
		1.12.6 Recipes
	1.13 Summary
	References
2 Baking process
	2.1 From the dough piece to the biscuit
		2.1.1 Biscuit structure
		2.1.2 Moisture content
		2.1.3 Colour
	2.2 Ingredients
		2.2.1 Wheat flour
		2.2.2 Wheat flours: typical specifications
			2.2.2.1 Wheat gluten
			2.2.2.2 Starch
		2.2.3 Sugar
		2.2.4 Leavening agents
			2.2.4.1 Yeast
			2.2.4.2 Sodium bicarbonate (“soda”)
			2.2.4.3 Ammonium bicarbonate (“vol”)
		2.2.5 Fats
	2.3 Baking process
		2.3.1 Development of the biscuit structure and texture
		2.3.2 Moisture removal
		2.3.3 Colour
		2.3.4 Summary
	References
3 Baking profiles
	3.1 Crackers
		3.1.1 Structure
		3.1.2 Moisture content
			3.1.2.1 Latent heat of evaporation: 539kcal/kg
		3.1.3 Colour
		3.1.4 Oven specification
		3.1.5 Baking profile
	3.2 Snack crackers
		3.2.1 Structure
		3.2.2 Baking process
		3.2.3 Moisture content
		3.2.4 Colour
		3.2.5 Baking times and temperatures
		3.2.6 Baking profile
	3.3 Semi-sweet biscuits
		3.3.1 Structure
		3.3.2 Moisture content
		3.3.3 Colour
		3.3.4 Oven specification
		3.3.5 Baking profile
	3.4 Short dough biscuits
		3.4.1 Structure
		3.4.2 Moisture content
		3.4.3 Colour
		3.4.4 Oven specification
		3.4.5 Baking profile
	3.5 Cookies
		3.5.1 Structure
		3.5.2 Moisture content
		3.5.3 Colour
		3.5.4 Oven specification
		3.5.5 Baking profile
	References
4 Biscuit design and output
	4.1 Cutter and moulding roll layouts
	4.2 Scrap and scrapless designs
	4.3 Semi-sweet biscuits
	4.4 Short dough biscuits and cookies
	4.5 Docker pins
	4.6 Oven band loadings
	4.7 Oven size and output
		4.7.1 Output calculation
	4.8 Summary
	Further reading
5 Heat transfer
	5.1 Radiation
		5.1.1 Wavelength
		5.1.2 Radiant heat transfer
		5.1.3 Distance
		5.1.4 Effect of radiation on the dough pieces
		5.1.5 Radio-frequency baking
		5.1.6 Near-infrared baking
		5.1.7 Microwave
	5.2 Conduction
		5.2.1 Baking with conduction
		5.2.2 Oven insulation
	5.3 Convection
		5.3.1 Convection baking
	5.4 Summary
		5.4.1 Radiation
		5.4.2 Conduction
		5.4.3 Convection
	Further reading
6 Oven designs
	6.1 Heat transfer methods
		6.1.1 Radiant heating
		6.1.2 Conduction heat transfer
		6.1.3 Convection baking
	6.2 Radiant heating
		6.2.1 Direct gas-fired ovens
		6.2.2 Conversion to electrical heating
		6.2.3 Summary
		6.2.4 Electric ovens
		6.2.5 Summary
		6.2.6 Indirect radiant ovens
		6.2.7 Summary
	6.3 Turbulence systems
	6.4 Conduction heat transfer
	6.5 Convection baking
		6.5.1 Direct convection ovens
		6.5.2 Indirect convection ovens
		6.5.3 Summary
		6.5.4 ‘Re-circ’ ovens
		6.5.5 Summary
	6.6 Hybrid ovens
		6.6.1 Direct gas-fired/indirect radiant ovens
		6.6.2 Direct gas-fired/convection ovens
	Further reading
7 Oven specifications
	7.1 Specifications for ovens: crackers
		7.1.1 Development of structure and texture
		7.1.2 Reducing moisture content
		7.1.3 Colour
		7.1.4 Final moisture content
		7.1.5 Recommended specification for a cracker oven
	7.2 Recommended oven specification for light carrier products, for example crispbreads, rusks
	7.3 Recommended oven specification for semi-sweet biscuits, for example Marie
	7.4 Recommended oven specification for short dough biscuits
	7.5 Specifications for ovens: soft dough cookies
	7.6 Danish butter cookies
	7.7 Modular oven design
	7.8 Calculation of oven zone lengths
		7.8.1 Example 1: Direct gas-fired oven for baking crackers (1.5×100m long)
			7.8.1.1 Heat input
		7.8.2 Example 2: Indirect radiant oven for baking a short dough biscuit, glucose type (1.25m×100m long)
			7.8.2.1 Heat input
		7.8.3 Example 3: Multipurpose oven 1.25m×91.0m
	Additional information on sources
		Biscuit oven manufacturers
		Oven band manufacturers
		Oven burner manufacturers
		Heat flux technology
8 Oven construction: direct gas-fired ovens
	8.1 Direct gas-fired baking chamber
		8.1.1 Baking chamber construction
		8.1.2 Conversion of gas-fired oven to electric
		8.1.3 Materials
		8.1.4 Dimensions
		8.1.5 Expansion joints
		8.1.6 Insulation
		8.1.7 Oven return band covers
		8.1.8 Explosion relief
		8.1.9 Inspection doors
		8.1.10 Cleanout doors
	8.2 Extraction system
		8.2.1 Fan specification
		8.2.2 Extraction: oven end hood
	8.3 Direct gas-fired oven: gas burner system
		8.3.1 Gas train
		8.3.2 Combustion air
		8.3.3 Temperature control system
		8.3.4 Flynn burners for direct gas-fired oven
		8.3.5 Infrared metal fibre burners
		8.3.6 Flynn infrared profile 7 distributor burner
	8.4 Control panels
		8.4.1 Main control panels
		8.4.2 Control panel construction
	Further reading
9 Oven construction: indirect radiant ovens
	9.1 Indirect radiant baking chamber
		9.1.1 Baking chamber construction and dimensions
		9.1.2 Expansion joints
		9.1.3 Heater module
		9.1.4 Radiant tubes
		9.1.5 Return ducts
		9.1.6 Circulation fan
		9.1.7 Extraction and turbulence
		9.1.8 Heat exchanger flue (chimney)
		9.1.9 Explosion relief
		9.1.10 Insulation
		9.1.11 Inspection doors
		9.1.12 Cleanout doors
	9.2 Indirect fired ovens: burners
		9.2.1 Weishaupt burners
			9.2.1.1 Technical description
			9.2.1.2 Specification: Weishaupt burner WG30N/1-C ZM LN (for 1.25m wide indirect radiant oven)
		9.2.2 Maxon burners
			9.2.2.1 Specification for 1.2m wide indirect radiant oven
				9.2.2.1.1 Maxon OVENPAK 515 gas/oil burner
				9.2.2.1.2 Maxon gas pipe trains
				9.2.2.1.3 Pilot gas train
				9.2.2.1.4 Oil pipe train
				9.2.2.1.5 Compressed air train
	Further reading
10 Heat recovery system
	10.1 Heat recovery system
		10.1.1 Calculations of hot air flow to the HRS zone
	Further reading
11 Oven construction: convection ovens
	11.1 Direct and indirect convection systems
	11.2 Baking chamber
		11.2.1 Baking chamber construction
		11.2.2 Convection plenums
		11.2.3 Return air
		11.2.4 Circulation fan
		11.2.5 Heater module
	Further reading
12 Oven construction: electric ovens
	12.1 Electric oven construction
	12.2 Electrical elements
	12.3 Conversion of direct gas-fired oven to electrically heated oven
	12.4 Oven efficiency
	12.5 Ovens with hot air circulation
		12.5.1 Indirect radiant oven
		12.5.2 Convection ovens
	12.6 Control systems
	Further reading
13 Oven conveyor bands (belts)
	13.1 Rolled wire-mesh bands (belts)
		13.1.1 Z-type bands
		13.1.2 Wire-mesh bands: skid bar supports
		13.1.3 Wire-mesh bands: support rollers
		13.1.4 Return band supports
		13.1.5 Wire-mesh oven band cleaning
		13.1.6 Wire-mesh oven band tracking
		13.1.7 Joining wire-mesh bands
		13.1.8 Dimensions of rolled wire-mesh belts
	13.2 Compound balanced weave bands
		13.2.1 Compound balanced weave band supports
		13.2.2 Band tracking for compound balanced weave bands
		13.2.3 Joining Ashworth bands
		13.2.4 Dimensions of compound balanced weave bands
	13.3 Steel bands
		13.3.1 Steel band supports
		13.3.2 Joining steel bands
		13.3.3 Steel band cleaners
		13.3.4 Steel band greasing
		13.3.5 Steel band tracking
	Further reading
14 Oven conveyor design
	14.1 Oven conveyor
	14.2 Feed end
		14.2.1 Oven terminal drums
	14.3 Delivery end
		14.3.1 Delivery end drum
		14.3.2 Oven drive
		14.3.3 Sprag clutch
		14.3.4 Uninterruptible power supply
		14.3.5 Stripping conveyor
		14.3.6 Oven end hood design
		14.3.7 Calculation of oven band tension
		14.3.8 Calculation of torque required for the conveyor drive
		14.3.9 Calculation of electric motor power
	Further reading
15 Process control systems
	15.1 Temperature control
		15.1.1 Direct gas-fired ovens
		15.1.2 Indirect radiant ovens
		15.1.3 Convection ovens
		15.1.4 Electric ovens
		15.1.5 Temperature monitoring and control
		15.1.6 Temperature controllers
		15.1.7 PID control
		15.1.8 Top and bottom temperature control
	15.2 Baking time
	15.3 Humidity
	15.4 Colour control
		15.4.1 Direct gas-fired ovens
		15.4.2 Indirect radiant ovens
		15.4.3 Colour measurement
	15.5 PLC control
		15.5.1 Specification for a PLC control system
	Further reading
16 Oven safety monitoring and alarm
	16.1 Oven band safety systems
		16.1.1 Oven band tracking
		16.1.2 Detection of the oven band position
		16.1.3 Oven band drive
		16.1.4 Emergency stops
		16.1.5 Emergency oven band drive
		16.1.6 Oven band tension system
	16.2 Oven burners and gas system
		16.2.1 Gas trains
		16.2.2 Gas system
		16.2.3 Main gas solenoid valves
		16.2.4 High-/low-pressure switch
		16.2.5 Zero gas governor
		16.2.6 Purge system
		16.2.7 Over-temperature safety
	16.3 Direct gas-fired ovens: manual control of top and bottom burners
		16.3.1 Air system
		16.3.2 Burner flame supervision
		16.3.3 Gas/air mixture
	16.4 Indirect-fired ovens: Weishaupt burners
		16.4.1 Excess temperature
	16.5 Extraction, combustion air and circulation fans
		16.5.1 Damper controls
	16.6 General safety equipment and instructions
		16.6.1 Guards and safety devices
		16.6.2 Operation safety precautions
		16.6.3 Cleaning and maintenance safety precautions
		16.6.4 Commissioning safety precautions
		16.6.5 Running the equipment without safety systems
		16.6.6 Protection of employees
		16.6.7 Emergency shutdown
	Further reading
17 Manufacture of biscuit ovens
	17.1 Why build the oven locally?
	17.2 Building baking ovens locally: the tasks and team
		17.2.1 The team and experience required
	17.3 Manufacturing drawings
	17.4 Control and safety systems
	17.5 Contractors
	17.6 Purchasing
	17.7 Shipping
	17.8 Installation
	17.9 Summary
	Further reading
18 Oven operation: direct gas-fired oven
	18.1 Starting the direct gas-fired oven: preparation
		18.1.1 Baking programme
		18.1.2 Burner pattern
		18.1.3 Before starting the oven
	18.2 Lighting the burners – direct gas-fired zone
	18.3 Heating up/start of production
	18.4 Shutting down the direct gas-fired oven
		18.4.1 When temperature drops to 100°C
	18.5 In the event of power failure
	18.6 In an emergency
	Further reading
19 Oven operation: indirect radiant oven
	19.1 Preparation
		19.1.1 Baking programme
		19.1.2 Before starting the oven
	19.2 Starting the oven
		19.2.1 Controls and settings
		19.2.2 Lighting the burners
		19.2.3 Heating up/production
		19.2.4 Damper controls
		19.2.5 Zone heating controls
		19.2.6 Extraction and turbulence dampers
	19.3 Shutting down the indirect radiant oven
		19.3.1 When temperature drops to 100°C
	19.4 In the event of power failure
	19.5 In an emergency
	19.6 Control of the heat recovery system
	Further reading
20 Oven efficiency
	20.1 Energy use
	20.2 Example of energy usage
		20.2.1 Product and oven
		20.2.2 Data from independent test results
		20.2.3 Energy to bake the product
		20.2.4 Heat loss from extraction from baking chambers
		20.2.5 Heat loss from return band
		20.2.6 Heat loss from the insulation and outer covers of the oven
		20.2.7 Heat loss from oven delivery end
		20.2.8 Heat loss from burner flues
		20.2.9 From the calculations above, the energy consumption of the oven per hour
	20.3 Comparison of oven efficiency for different oven types (based on actual installations)
	20.4 Calculations for the energy required to bake biscuits
		20.4.1 Rotary moulded biscuit
		20.4.2 Semi-sweet biscuit
		20.4.3 Cracker
	References
21 Energy for biscuit baking
	21.1 Combustion data: natural gas
		21.1.1 Combustion process
		21.1.2 Carbon dioxide emission from burning natural gas
	21.2 The biscuit industry carbon footprint
		21.2.1 Climate change and greenhouse gases
		21.2.2 Energy usage for baking
		21.2.3 Consumption of gas for baking
		21.2.4 The carbon footprint
		21.2.5 Energy sources for biscuit baking
	21.3 Generating electricity from renewable energy sources
		21.3.1 Power generation costs for renewable energy
		21.3.2 Development of electricity generation from renewables
		21.3.3 Future developments for biscuit baking
	21.4 Solar energy
		21.4.1 New biscuit bakeries
		21.4.2 Solar energy for a new bakery
	Further reading
22 Oven inspection and audit
	22.1 Oven performance
		22.1.1 Output
		22.1.2 Product specification/compliance
		22.1.3 Energy usage
	22.2 Oven band
	22.3 Baking chamber
	22.4 Gas and oil trains
	22.5 Gas burners
		22.5.1 Burners: direct gas-fired ovens
		22.5.2 Burners: indirect-fired ovens
	22.6 Temperature and humidity control systems
		22.6.1 Heat flux
		22.6.2 Measurement of heat flux
		22.6.3 Baking temperature and humidity
	22.7 Controls and electrical panels
	22.8 Reporting
	Further reading
23 Oven maintenance
	23.1 Preparation
	23.2 New equipment
	23.3 Routine maintenance
		23.3.1 Safety devices
	23.4 Mechanical components
		23.4.1 Welded components
		23.4.2 Driving chains and belts
		23.4.3 Motors and drives
		23.4.4 Steam lines and fittings
		23.4.5 Air lines and fittings
		23.4.6 Seal and gaskets
		23.4.7 Bearings
		23.4.8 Conveyor belts
		23.4.9 Oven band tension
		23.4.10 Pneumatic tension arrangement
		23.4.11 Band pressure switch
		23.4.12 Oven band tracking
		23.4.13 Bearings for oven band support rollers
		23.4.14 Explosion panels
		23.4.15 Oven flues
		23.4.16 Pulleys for fans
		23.4.17 Fans
	23.5 Electrical maintenance
		23.5.1 General
		23.5.2 Cleaning
		23.5.3 Relays
		23.5.4 Inspection schedule for relays
		23.5.5 Temperature controllers
		23.5.6 Connections and leads
		23.5.7 Fuses
		23.5.8 Earth leakage protection devices
		23.5.9 Clutches and brakes
		23.5.10 Transistor/solid-state devices
		23.5.11 Limit switches
		23.5.12 Proximity detectors (inductive or capacitive)
		23.5.13 Plug-in timers
		23.5.14 Battery safety
	23.6 Maintenance schedule
		23.6.1 Each day
		23.6.2 Each week
			23.6.2.1 Driving belts
			23.6.2.2 Fan filters
			23.6.2.3 Inspection and access doors
			23.6.2.4 Oven lamps
			23.6.2.5 Dampers
			23.6.2.6 Emergency drive
			23.6.2.7 Oven ignition
			23.6.2.8 Oven band
		23.6.3 Every 12 months
			23.6.3.1 Burners and gas equipment
	23.7 Oven cleaning
	23.8 Standard lubrication
		23.8.1 Ball/roller bearings with provision for lubrication
		23.8.2 Sealed ball bearings
		23.8.3 NSK-RHP self lube bearings
		23.8.4 Recommended lubricants
		23.8.5 Every 200 h
		23.8.6 Every 2500 h
		23.8.7 Every 5000 h
		23.8.8 Each year
	23.9 Maintenance log or record
	23.10 Recommended spare parts
		23.10.1 Gas system
		23.10.2 Weishaupt burners
		23.10.3 Maxon burners
		23.10.4 Flynn burners
		23.10.5 Electrical/temperature control parts
		23.10.6 Mechanical parts
	References
Appendix 1 Ingredients for biscuits: an introduction
	1 Flour
		1.1 Wheat flour
		1.2 Corn flour
	2 Sugars and syrups
		2.1 Sucrose
		2.2 Glucose syrup
		2.3 Cane syrup 80%
		2.4 Invert syrup 70%
		2.5 Fructose syrup 80%
		2.6 Malt extract 80%
	3 Fats
		3.1 Dough fat
		3.2 Butter
		3.3 Palm oil
		3.4 Coconut oil
	4 Dairy products
		4.1 Whole egg powder
		4.2 SMP, FCMP—skimmed milk powder, full cream milk powder
	5 Leavening agents
		5.1 Yeast (fresh)
		5.2 Ammonium bicarbonate (“Vol”) (NH4)HCO3
		5.3 Sodium bicarbonate (“Soda”) NaHCO3
		5.4 ACP—acid calcium phosphate
		5.5 SAPP or PURON—sodium acid pyrophosphate
	6 Emulsifiers
		6.1 Lecithin
		6.2 GMS—Glycerol monostearate
	7 Flavour enhancers
		7.1 Salt
		7.2 Monosodium glutamate (MSG) C5H8NO4Na
		7.3 SSL—sodium stearoyl lactylate
	8 Preservative
		8.1 SMS—Sodium metabisulphite Na2S2O5
	9 Enzymes
		9.1 Proteolytic enzymes
	Bibliography
Appendix 2 Specification of a multi-purpose oven 1.27×91.9m
	1 Oven feed end
	2 Direct gas fired zone 31.9m long with three heat control zones
	3 Direct gas fired burners and gas equipment
		3.1 Gas train
		3.2 Air supply
		3.3 Burner system
		3.4 Automatic temperature control
	4 Indirect radiant oven
		4.1 Oven burners
		4.2 Gas train
		4.3 Automatic temperature control
		4.4 Turbulence/convection system
		4.5 Thermocouples and pressure gauges
	5 Oven band
		5.1 Oven band cleaner
	6 Delivery end section
		6.1 Oven end extraction hood
	7 Control panels
	8 Oven safety systems
		8.1 Oven band
		8.2 Ignition
		8.3 Purge system
		8.4 Over temperature
		8.5 Power failure
	9 Components and finishes
		9.1 Electrical installation
		9.2 Components
		9.3 Finishes
	Bibliography
Appendix 3 Oven manufacturers
	1 China
		1.1 Dongguang Furong Food Machinery Factory
		1.2 Evergrowing Food Machinery Co. Ltd
		1.3 Shanghai Kuihong Food Machinery
		1.4 Sinobake, Guandong Shunde Huaji Industrial Co
		1.5 Skywin Foodstuff Machinery Co. Ltd
		1.6 Zhongshan Dingson Food Machinery Ltd
		1.7 Zhuhai Hong Fu Mechanical Manufacturing Co. Ltd
	2 EUROPE
		2.1 Aasted ApS
		2.2 Baker Perkins Ltd
		2.3 Baker Perkins Inc
		2.4 Bühler Group
		2.5 GEA IMAFORNI INT'L S.p.A
		2.6 Laser Srl
		2.7 Pek Makina
		2.8 Polin, Ing POLIN E C. SpA
		2.9 Senius Equipment Aps
		2.10 Spooner Vicars Bakery Systems
		2.11 TMFCT – Bonnand Lornac
		2.12 Werner & Pfleiderer
	3 India
		3.1 Bake-o-Nomic Corp
		3.2 Besto Oven Industries
		3.3 Esspee Engineers, Kolkata
		3.4 New Era Machines
		3.5 Ovenman Industries Private Ltd
	4 Japan
		4.1 Misuzu Koki Co Ltd
		4.2 Naigai-Vicars
	5 Korea
		5.1 Dong Yang Food Machinery Co. Ltd
	6 United States
		6.1 Baker Perkins Inc
		6.2 Reading Bakery Systems
Appendix 4 Oven band manufacturers
	1 Agrati La Bridoire Sarl
	2 Ark Engineers
	3 Ashworth Bros. Inc
	4 Audubon
	5 Berndorf Band Gmbh
	6 Bharat Wire Mesh Company
	7 Cambridge Engineered Solutions
	8 Consol Machinery (Canton) Co. Ltd
	9 Durgesh Industries
	10 Heights Wire Belt Factory
	11 IPCO
	12 Rexnord Inc
	13 Shri Jai Maharani Industry
	14 Steinhaus GmbH
	15 Yangzhou Jiangdu Huada Metal Mesh Belt Factory
	16 Yangzhou Jinrun Mesh Belt Manufacturing Co
Index