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Biscuit Baking Technology, 2nd Edition

Biscuit process and engineering manual – now available for Pre-Order at www.store.elsevier.com/9780128042113

For author’s 30% discount use code: ATR30

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Author: Iain Davidson

Expected release: 01 February 2016

Imprint: Academic Press

Print book ISBN: 9780128042113

Pages: 384

Dimensions: 229 x 152

Print Book: GBP 106.25

Paperback: GBP 125.00

 

 

 

 

 

A manual for designers and operators on the biscuit oven – baking technology

Table of Contents

INTRODUCTION

1 THE BISCUITS

2 BAKING PROCESS

3 BISCUIT DESIGN AND OUTPUT

4 HEAT TRANSFER

5 OVEN DESIGNS

6 OVEN SPECIFICATIONS: hybrid ovens

7-1 CONSTRUCTION: Direct Gas Fired Ovens

7-2 OVEN CONSTRUCTION: Indirect Fired Ovens

7-3 HEAT RECOVERY SYSTEM

8 OVEN CONVEYOR BANDS

9 OVEN CONVEYOR DESIGN

10 PROCESS CONTROL SYSTEMS

11 OVEN SAFETY MONITORING AND ALARM

12-1 OVEN OPERATION: Direct Gas Fired Oven

12-2 OVEN OPERATION: Indirect radiant Oven

13 OVEN EFFICIENCY

14 OVEN INSPECTION AND AUDIT

APPENDIX 1 Ingredients for biscuits

APPENDIX 2 Oven maintenance

APPENDIX 3 Oven manufacturers

APPENDIX 4 Oven band manufacturers

Pre-order at  www.store.elsevier.com/9780128042113 

For 30% author’s discount use code: ATR30

 

Baker Pacific Ltd. 3905 Two Exchange Square, 8 Connaught Place, Hong Kong

Tel. +852 2522 1114       email: bakerman@dircon.co.uk      

LOGO 2014

Training courses

Baking process and engineering – baking by infrared

  Individual company programs 

Button    The training programs are designed to suit each company’s requirements. Especially valuable for production management, engineering, maintenance staff  and oven operators.

Button    The programs include class work with Power Point presentations, discussion and  questionnaires. The training may also includes on-site training by our senior engineer. This can cover trouble shooting, oven operation, maintenance, planning oven up-grades and efficiency improvements

Button    Normally 2 – 3 modules are presented each day and the complete course is delivered in a 5 day week

Button    Each of our technicians has over 35 years experience as engineers in the biscuit industry in factories in Europe, Asia, North and South America

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Baker Pacific oven installations baking by infrared radiation

Training Modules

Complete course in one week

Day 1   Introduction / the biscuits / baking process / biscuit design and output

Day 2   Heat transfer / oven designs and specifications

Day 3   Oven bands and conveyor design

Day 4   Oven control / safety systems / oven operation

Day 5   Oven maintenance / inspection and audit / oven efficiency / heat recovery

 

Our training program has exclusive information on:

Button   All types of oven designs / direct and indirect fired / radiant / convection / re-circ ovens

Button   Specifying ovens for different applications for biscuits, cookies and crackers

Button   Setting standards and guarantees for suppliers

Button   Oven bands: types, tracking, cleaning, supporting on skids and rollers

Button   Oven efficiencies with actual data from trials

Button   Energy usage and energy loss

Button   Heat recovery system to save capital and operating costs

Button   Oven operation and maintenance

Button   Oven inspections and audits

 500 Power Point presentation slides

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Complete course given by a senior Baker Pacific engineer USD 4,500.00

(excluding travel and living expenses)

Alternative: complete course materials for in-house presentations USD 240.00

To order please contact Baker Pacific at bakerman@dircon.co.uk

 

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Heat transfer for baking

Three modes of heat transfer are used in baking biscuits: radiation, conduction and convection.

Heat transfer - ovens   

1. Direct Gas Fired / Indirect Radiant oven        2. Conduction from steel band          3. Convection oven 

 Radiation

All objects above a temperature of absolute zero radiate energy to their surroundings. This energy or radiation is emitted as electromagnetic waves which travel at the speed of light. The waves may travel through a vacuum or other medium. When they impact an object, they are partially absorbed and partially reflected. Good emitters are also good absorbers of thermal radiation.

Infra-red radiation is in the wavelength band of 0.7-300 microns (above visible light). Higher temperatures produce shorter wave lengths. Typical wavelengths in a radiant oven are around 4.6 – 6.4 microns, which provides good heat penetration of the dough pieces. Infrared radiation for baking is emitted principally by the DGF burner flames and by the radiant tubes in an Indirect Radiant oven.

Radiant tubes and burners

Radiant tubes in an Indirect Oven                                        High rate direct gas fired burners

The most important mode of heat transfer for baking is infrared radiation, which has the following advantages:

  • Penetrative heat transfer: Infrared radiation penetrates biscuit doughs by approximately 4mm, (depending on wavelength and moisture content). It is the only heat transfer mode to truly bake the product from the centre. This is the key advantage of baking by infrared radiation
  • Biscuit structure: because radiation penetrates the dough pieces, it is essential to achieving good structure with optimum volume and texture and is always the main mode of heat transfer in the first part of the baking process
  • Even moisture content: radiant baking ensures a low moisture gradient from centre to the outer surface of the biscuit. It is the best heat transfer mode to  avoid “checking” (cracks appearing in the biscuit after baking)
  • Efficiency: heating of the surrounding air in the baking chamber is not necessary, which lowers energy consumption
  • Colouring: radiation enables highlighted colour contrasts for crackers and rotary moulded products, whereas convection gives an overall, bland, even colour
  • Versatile: infrared baking is suitable for all types of biscuit

Conduction

Conduction transfers heat from the oven band directly to the base of the dough pieces. The heat transfer is dependent on the temperature and heat mass of the oven band and the surface area of the band in contact with the dough piece. With steel bands and heavy mesh bands this approximates to full contact and is very effective.

Ovens with band pre-heat can quickly transfer heat into the base of the dough pieces and achieve rapid development of the biscuit structure and texture; this is particularly valuable for cracker baking.

Convection

Convection baking uses hot air jets which impinge directly on the top of the dough pieces and the underside of the oven band. This system effectively dries and colours the surface of the dough pieces. However it produces a hard, dry skin on the dough pieces and will prevent good expansion and “lift” of the product if used at the start of the baking process. Also it is a cause of a moisture gradient between the surface (very dry) and the centre of the biscuit (more moist). This may result in “checking”, (cracking of biscuits after baking), unless the moisture gradient is reduced after baking.

Convection v Radiation v Conduction

 

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