Table of Contents Introduction an Objectives ................................................................................................................................ xix

1

Mashing Objectives and Methodology ............................................................................................. 1 1.1

The key objectives of mashing ............................................................................................ 1 1.1.1

Mash filterability ..................................................................................................... 1

1.1.2

Wort clarity ............................................................................................................. 1

1.1.3 Starch conversion rate and mash extract yield ............................................................. 1 1.1.4

Attenuation limit ...................................................................................................... 1

1.1.5

Fermentability .......................................................................................................... 2

1.1.6

Beer filterability ...................................................................................................... 2

1.1.7 Wort composition ...................................................................................................... 2 1.2

Traditional and Modern methods and procedures of mashing ............................................. 4

1.2.1

2

“In situ” mashing and “stirred and transferred mashing ............................................... 4

1.2.2

“In situ” mashing-classic pale ale brewing ................................................................. 4

1.2.3

Stirred and transferred mashing.................................................................................. 4

1.2.4

Pale lager malts ........................................................................................................ 4

1.2.5

Adjunct brewing........................................................................................................ 5

1.2.6

Wort composition requirements .................................................................................. 6

Mashing lngredients ....................................................................................................................... 7 2.1

Malt ..................................................................................................................................... 8 2.1.1 Pale lager malts ......................................................................................................... 11 2.1.2

Pale ale malts .......................................................................................................... 12

2.1.3

Dark and speciality barley malts ............................................................................... 13

2.1.4 Wheat malt ............................................................................................................... 13 2.1.5 Naked (hull-less ) barley malt ..................................................................................... 14 2.2

Adjuncts .............................................................................................................................. 14 2.2.1

Definition and types of adjunct ................................................................................. 14

2.2.2 Main reasons for using adjuncts ................................................................................. 14 2.2.3 Biochemical and technological aspects of mash tun adjuncts......................................... 15 2.2.3.1

The carbohydrate fraction ............................................................................ 15

2.2.3.2

The nitrogen fraction .................................................................................. 18

2.2.3.3

The lipid fraction ......................................................................................... 18

2.2.3.4

Polyphenols, tannins and anthocyanogens ...................................................... 18

2.3

Exogenous Enzymes ............................................................................................................. 18

2.4

Brewing Water .................................................................................................................... 18 2.4.1 Introduction .............................................................................................................. 18

vii

2.5

2.6

3

2.4.2

Water and types of beer ............................................................................................. 19

2.4.3

Effect of mashing water composition ......................................................................... 20 2.4.3.1

Hardness .................................................................................................... 20

2.4.3.2

General reactions of ions in water ................................................................ 21

2.4.3.3

Water alkalinity ........................................................................................... 22

2.4.3.4

Effect of decreasing acidity on the process .................................................. 23

2.4.3.5

Influence of different ions on wort and beer properties .................................. 24

Brewing salts and acids ....................................................................................................... 27 2.5.1

Conditioning of mashing water................................................................................... 27

2.5.2

Acidification ............................................................................................................ 27

Biological acidification of wort ........................................................................................... 27

The Biochemistry and Procedures of Mashing................................................................................. 28 3.1

Mashing Procedures ............................................................................................................ 28 3.1.1 100 %, Malt mashes .................................................................................................. 28 3.1.2 Malt adjunct ratios above 50% .................................................................................... 32 3.2.3 Barley, sorghum and adjunct brewing with less than 20% malt, or exclusively with exogenous enzymes ........................................................................................... 32

3.2

Description of the mashing process (stirred and transferred mashing) ............................... 33 3.2.1 Hydration , mashing in and mash-vessel filling ........................................................... 35 3.2.2 Mashing (after mash-vessel filling) ............................................................................ 36 3.2.3 Mash heating above 75°C, mash-vessel emptying and transfer to lauter tuns Or thin-bed filters ...................................................................................................... 37

3.3

Enzymes involved in malt mashing ...................................................................................... 37 3.3.1 Endogenous enzymes of plant origin ........................................................................... 38 Endogenous enzymes of microbial origin ................................................................. 40 3.3.3 Exogenous enzymes .................................................................................................. 40 3.3.3.1

Thermostable α-amylases ............................................................................ 40

3.3.3.2

Thermostable β-glucanases .......................................................................... 41

3.3.4 Malt enzymes that interfere in lipid metabolism and lipid-polyphenol oxidation ............ 41 3.4

Enzyme extraction , activity and inactivation ..................................................................... 41 3.4.1 Enzyme extraction .................................................................................................... 41 3.4.2 Enzyme activity ........................................................................................................ 42 3.4.3 Enzyme inactivation .................................................................................................. 43

3.5

Substrates involved in malt mashing and substrate enzyme interaction .............................. 43 3.5.1

Proteins ................................................................................................................. 44

3.5.2

Starch ................................................................................................................... 44

viii

3.5.2.1

Gelatinizaion .............................................................................................. 45

3.5.2.2

Liquefaciton ............................................................................................... 45

3.5.2.3

Starch hydrolysis ........................................................................................ 45

3.5.3 Pentosans and β-Glucans ........................................................................................... 46

3.5.4 3.6

3.7

Phyntosans ................................................................................................. 46

3.5.3.2

β-Glucans ................................................................................................... 46

Phytates ................................................................................................................... 48

Process Parameters ............................................................................................................. 48 3.6.1

Particle size reduction, particle size distribution and method of milling ...................... 49

3.6.2

Mash rates .............................................................................................................. 51

3.6.3

Shear and stirring .................................................................................................... 53

3.6.4

Oxygen entrainment ................................................................................................ 54

3.6.5

pH Management ...................................................................................................... 56

3.6.6

Time - rate limiting steps ......................................................................................... 56

Control of unwanted reactions in malt mashes ...................................................................... 57 3.7.1 3.7.2

3.7.3

4

3.5.3.1

Excessive polyphenol oxidation ................................................................................ 57 Lipid oxidation and trans - 2- nonenal in pale lager malt mashes ................................. 58 3.7.2.1

Lipid oxidation ........................................................................................... 58

3.7.2.2

Trans-2-nonenal .......................................................................................... 59

3.7.2.3

The nonenal potential .................................................................................. 59

Strecker degradation ................................................................................................. 60 3.7.3.1

Relation to FAN levels ................................................................................ 60

3.7.3.2

Interaction of Strecker degradation and liquid oxidation ................................. 60

3.8

Conversion of adjuncts in a malt mashing operations .......................................................... 60

3.9

References ........................................................................................................................... 62

Mashing Equipment ....................................................................................................................... 64 4.1

Single Temperature Infusion mashing ................................................................................. 64

4.2

Stirred and transferred mashes ........................................................................................... 65

4.3

Mash Conversion and Cooking Vessels ............................................................................... 68

4.4

4.3.1

Adjunct pre-mashing in a mash cooker. ...................................................................... 68

4.3.2

Mash Conversion Vessel (MCV) design ..................................................................... 68

Malt storage to completion of mashing-in/mash-vessel filling ............................................. 70 4.4.1

Separated operations ............................................................................................... 70

4.4.2

Integrated operations ............................................................................................... 70

4.5

Mashing from mash-vessel filling to saccharification at ≥ 72 °C ......................................... 71

4.6

Mashing-off and mash transfer ........................................................................................... 72

ix

4.6.1

Mashing-off .............................................................................................................. 72

4.6.2

Mash transfer ........................................................................................................... 72 4.6.2.1

Stirring during mash transfer ........................................................................ 72

4.6.2.2

Mash transfer to lauter tuns and thin-bed filters ............................................ 72

4.6.2.3

Mash-transfer and mash distribution before entering lauter tuns or thin-bed filters............................................................................................. 73

5

Theory of Mash Separation ............................................................................................................ 74 5.1

Objectives of mash separation ............................................................................................ 74

5.2

Existing Techniques............................................................................................................. 74 5.2.1

5.2.2

5.3

Mash tuns and lauter tuns ............................................................................ 74

5.2.1.2

Mash filters ................................................................................................ 76

5.2.1.3

Comparison of lauter tuns and thin-bed filters ............................................... 84

Problem areas and solutions ...................................................................................... 86 5.2.2 1

Sparging ..................................................................................................... 86

5.2.2.2

Mash distribution during mash transfer and filling ........................................ 88

5.2.2.3

Milling and mashing in ................................................................................ 88

Conditions required for trouble-free mash separation ......................................................... 88 5.3.1

5.3.2

5.4

Historical Development- ........................................................................................... 74 5.2.1.1

Mash filterability ..................................................................................................... 88 5.3.1.1

Intrinsic mash filterability ........................................................................... 88

5.3.1.2

Engineering design and filterability .............................................................. 90

The theory of mash separation ................................................................................... 91

5.3.3

Extract yields ......................................................................................................... 92

5.3.4

Effluent and spent grain removal ................................................................................ 94

Specific requirements as regards the form and size of the husk fraction of pale lager malt ......................................................................................... 94

5.5

Husk-free mashes ................................................................................................................. 97

5.6

The impact of malting, milling, mashing-in, mashing and mashing-of on mash separation .......................................................................................... 98

5.7

The impact of milling, mashing and mash separation on downstream operations.......................................................................................................................... 101

5.8 6

Conflicting targets for wort production .............................................................................. 101

Mash Separation Equipment ........................................................................................................... 102 6.1

The British infusion mash tun ……………………………………………………………………….. 102 6.1.1

Introduction ............................................................................................................ 102

6.1.2

Description of the mash tun ...................................................................................... 102

x

6.2

6.1.3

Operational description ............................................................................................. 103

6.1.4

Operating and control principles ............................................................................... 105

6.1.5

Limits of application ................................................................................................ 107

6.1.6

Why is this technique described although considered superseded? ................................ 107

The Lauter tun ................................................................................................................... 108 6.2.1

The lauter tun used in combination with conditioned steep wet milling Huppman AG ........................................................................................................... 108

6.2.2

6.2.3

6.2.1.1

Working principles ...................................................................................... 108

6.2.1.2

Operational description ............................................................................... 110

6.2.1.3

Automatic control principles ........................................................................ 113

6.2.1.4

Typical performance .................................................................................... 114

6.2.1.5

Special design features ................................................................................. 115

6.2.1.6

Troubleshooting .......................................................................................... 118

6.2.1.7

Safety ......................................................................................................... 119

6.2.1.8

Application fields and limits of application .................................................. 119

6.2.1.9

Development areas ....................................................................................... 119

Mash separation by lauter tun - Briggs of Burton PLC………………………………………120 6.2.2.1

Working principles ..................................................................................... 120

6.2.2.2

Specific preset operating conditions .............................................................. 122

6.2.2.3

Briggs lauter tun, operational description ..................................................... 124

6.2.2.4

Typical lauter performance .......................................................................... 128

6.2.2.5

Process automation principles ....................................................................... 130

6.2.2.6

Safety ......................................................................................................... 130

6.2.2.7

Special design features, Briggs lauter tun ..................................................... 130

6.2.2.8

Potential process improvements ................................................................... 133

Mash separation by "ring" lauter tun (Pegasus) Krones AG Steineker Plant ....................................................................................... 134

6.3

6.2.3.1

Working principles ..................................................................................... 134

6.2.3.2

Specific operating conditions........................................................................ 135

6.2.3.3

Pegasus lauter tun - Operational description ................................................ 136

6.2.3.4

Typical lauter performance ......................................................................... 137

6.2.3.5

Process automation .................................................................................... 138

6.2.3.6

Safety ....................................................................................................... 138

6.2.3.7

Applications and limits .............................................................................. 138

The mash filter ................................................................................................................... 139 6.3.1

Membrane assisted thin-bed filters - Meura SA ……………………………………………. 139 6.3.1.1

Working principles ..................................................................................... 139

6.3.1.2

Technical Description .................................................................................. 139

6.3.1.3

Filtration Process: Overview ....................................................................... 140

6.3.1.4

Preset conditions for mash separation using a membrane mash filter. .............. 140

6.3.1.5

Operational description of the membrane assisted filter .................................. 142

6.3.1.6

Automatic process control principles ............................................................ 148

6.3.1.7

Typical performance figures for optimal pre-set conditions ........................... 148

6.3.1.8

Construction and design features of a membrane

6.3.1.9

Troubleshooting .......................................................................................... IS3

assisted mash filter ..................................................................................... 151

xi

6.3.1.10

Safety ........................................................................................................ 153

6.3.1.11 Application fields and Limits of application ................................................. 154 6.3.2

The recessed chamber plate mash filter - Nordon & Cie………………………………….. 154 6.3.2.1

Introduction ................................................................................................ 154

6.3.2.2

Materials of construction ............................................................................. 155

6.3.2.3

Mash filter design ....................................................................................... 155

6.3.2.4

Specific preset conditions ............................................................................ 156

6.3.2.5

Operational description ............................................................................... 158

6.3.2.6

Typical performance characteristics ............................................................. 162

6.3.2.7

Troubleshooting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163

6.3.2.8

Process control and automation .................................................................... 163

6.3.2.9

Safety ......................................................................................................... 164

6.3.2.10 Specific design features .............................................................................. 165 6.3.2.11 Applications and limits ............................................................................... 165 6.3.3

7

8

Mash separation by thin layer chamber mash filter - Ziemann TCM mash filter ............. 165 6.3.3.1

Working principles and technical description ................................................ 165

6.3.3.2

Specific operating conditions........................................................................ 166

6.3.3.3

Ziemann TCM mash filter-Operational description ........................................ 167

6.3.3.4

Automation ................................................................................................ 169

6.3.3.5

Typical performance figures ........................................................................ 169

6.3.3.6

Safety ......................................................................................................... 170

6.3.3.7

Application fields ....................................................................................... 170

Research and development ................................................................................................................. 171 7.1

Malt .................................................................................................................................... 171

7.2

Modelling mashing ............................................................................................................. 171

7.3

Release of β -glucans at temperatures exceeding 62° - 64 °C ................................................ 17l

7.4

The nonenal- and carbonyl-potential of wort ...................................................................... 171

7.5

The foam potential of wort ................................................................................................. 172

7.6

Continuous mashing ............................................................................................................ 172

7.7

Mash separation.................................................................................................................. 173

7.8

De-emulsification and flocculation during mash filtration .................................................. 173

Mashing and mash separation -Troubleshooting and potential conflicts ............................................ 174 8.1

Troubleshooting ................................................................................................................. 174

8.2

Potential conflicts during mashing ...................................................................................... 175

xii