Modernization of malt quality analysis to better inform brewers, maltsters and barley breeders - functional tests and

future opportunities

Dr Evan Evans

School of Plant Science

University of Tasmania

AustraliaAustralian Barley Biochemistry & Brewing Research

Barley Malting Quality … from Grass to Glass.

Introduction• If it is not malting quality it is feed!

Big $ implications for grower profits - gross margins

• Malting quality specifications are the basis commercial transactions in the malt quality value chain

• Good malt quality reduces maltster and brewer risk - $ premiums

Grower Grain trader Maltster Brewer

How accurately do current malt quality specifications predict malt quality?

What is the malt quality risk premium? Can we lower it?

$$$ $$$

Lower risk

Higher risk

What does the brewer really want to know?• How much does it cost?

• How consistent & predictable is the malt quality?

• How much beer will a tonne of malt make?

• Will there be any brewing/fermenting difficulties (ie PYF)?

• Will there be any production difficulties (ie lautering, filtration)?

• Will the beer quality match specifications (ie color, foam, flavor)?

A Typical Malt Quality Specification Report

“Functional” Malt Quality Specifications: Barry Axcell, SABMiller

1. Mashing procedure - how relevant is the Congress mash?

2. Mash filtration performance: lautering and mash filter?

3. The value of spectrophotometric measures of malt quality ie NIR?

4. DP enzymes, individual testing and fermentability prediction?

5. Modification of proteins and non-starch polysaccharides?

6. Lipids, lipoxygenase, flavor and foam?

7. Microbial assessment, the good, the bad and PYF?

8. Beer clarity - haze

Malt Quality Specifications Considered

“New Malt Quality Specifications must be “accurate” “rapid” and “cost efficient”

Mashing Procedure?

Extract, KI, Color, WBG, AAL, FAN…

How relevant is the

Congress mash?

Congress vs modern commercial mashes

The influence of mash in temperature on AAL and

sugar composition

5.7%

Grist grinding - disc mill vs 6 roller mill

Conclusion: Brewers consider 0.7mm grind “closer”to reality

6 roller mill Disc mill with setting:

Commercialgrist

0.2 mmgrind

0.7 mmgrind

1.0 mmgrind

Sieve Proportions

1.25 mm 46.4% 2.1% 9.8% 27.2%

1.0 mm 8.5% 1.8% 14.6% 20.2%

0.50 mm 16.4% 9.1% 41.5% 24.1%

0.25 mm 9.5% 37.9% 13.0% 9.7%

0.125 mm 6.0% 17.1% 6.5% 5.2%

Pan 13.3% 32.1% 14.6% 13.7%

Grist MillingMash in 65°C 50 min, 1:4 ratio, finish 74°C,

0.22mM CaSO4

Conclusion:Substantial impact,select 0.7mm as closerto brewers reality

Grist to water ratioMash in 65°C 50 min,

0.7mm grind, finish 74°C

0.22-0.3 mM CaSO4

Conclusion: Grist : water important, choose 1:3 as closer to commercial practice

Mash durationMash in 65°C, 1:3 ratio

0.7mm grind, finish 74°C

0.3 mM CaSO4

Conclusion: Mash duration important.use 60min as this givesclose to max fermentabilityand same as IoB protocol

Mashing protocol comparison summary

Comparison Congress and Final 65°C protocols

n= 29, * LSD (P<0.05) calculated upon duplicate samples of a selection of nine of the malt samples

Extract and AAL Comparison (n=29):Congress and Final 65°C Protocols

MLR - AAL comparison of mashing protocols

Mash filtration performance:

lautering and mash filters?

As simple 25min test of lautering performanceA bolt on to mash extract evaluation

As simple 25min test of lautering performanceA bolt on to mash extract evaluation

The Value of Spectrophotometric

Measures of Malt Quality?

Such as NIR and IR

• NIR regularly used for grain/malt protein and moisture - good accuracy• Wort and alcohol in beer (ie Anton Paar Alcolyzer - very accurate)• Breeders use for culling of inferior lines for:

- whole grain (barley - ads and limits) vs whole malt- extract- DP/ -amylase- -glucan / viscosity- FAN and soluble protein- parameters such as husk content and grain color- LOX?

Spectrophotometric Measures of Malt Quality

Future?• NIR and image analysis?• IR combined with statistical evaluation - new opportunities?

- Lipids in wort?• Other components?

DP Enzymes, Individual Testing

and Fermentability Prediction?-amylase,

-amylase, limit dextrinase(thermostability LD and -amylase)

ß-amylase

limit dextrinase

-amylase Reducingend

-glucosidase

Starch is degraded by the four diastase enzymes

201510500

20

40

60

80

100Sd1Sd2-HSd2-LSd3

Time (min)

Res

idua

l act

ivity

(%)

Relative Rates of Irreversible Thermal Inactivationof ß-amylase in Barley Extracts at 60 °C

Sd2L: low -amylasethermostability ie Schooner

Sd1: intermediate -amylase thermostability, ie Baudin, Gairdner AC Metcalfe, Harrington, Morex

Sd2H: high -amylase thermostability, ie Buloke, Flagship,Haruna nijo.

828078760

10

20

30

40

Fermentability (AAL %)84828078

40

60

80

100

120Sd1Sd2-HSd2-L

Fermentability (AAL%)

Sd1Sd2-HSd2-L

DP (oL)

Residual-amylaseActvity (%)

Relationship between -amylase thermostability and wort fermentability in 42 commercial samples( Extracted from Eglinton et al., 1998)

2 % point AAL advantage forSd2H varieties

Evans et al., 2005, J. Am. Soc. Brew. Chem. 63:185-198

AAL = 69.9 + 0.017*a + 9.60*b + 0.195*c + 0.007*d + 0.538e - 0.001*d*e

r2 = 0.91

Parameters DP Enzyme MLR (multi linear regression): a = -Amylase activity, b = Total limit dextrinase activityc = KI (%)d = Total -amylase activitye = -Amylase thermostability (%)

Predicting AAL from malt characteristics

Case study 1:Commercial brewery fermentability variability

explained by DP enzymes

Commercial brewery fermentability variability explained by DP enzyme levels: Case study 2

An Improved malt description

Impact of Blending on Fermentability

varietySd

typeb-amy

%Thermb-amy

(U/g dw)a-amy

(U/g dw)LD

(U/kg dw)LD

%Thermb-glucanase (U/kg dw)

KI DP TotalProtein

Baudin Sd1 4.9 707 177 334 54.8 364 48.0 453 11.8Schooner Sd2L 0.7 350 165 318 47.4 118 48.3 184 11.0

Flagship Sd2H 16.3 537 208 323 54.2 293 46.0 365 11.2Schooner Sd2L 0.7 350 165 318 47.4 118 48.3 184 11.0

Combined testing of DP enzymes by

MegaZyme assays• Ceralpha• Betamyl• Limit DextriZyme

See: Evans, D.E., (2008) Journal American Society of Brewing Chemists, 66:215-222

Further development - Use of robots?

Lipids, Lipoxygenase,

Flavor and Foam?

Lipoxygenase (LOX 1 and LOX2) • Production of off flavours - beer flavour stability reduced

• Production of lipid hydroperoxides - beer foam stabilty reduced

• Lipoxygenase 1 null lines: Sapporo, Carlsberg-Heineken

Lipids, Lipoxygenase … Flavor and Foam

Lipids• Substrate for lipoxygenase (linoleic acid C18:2)

• Required for yeast viability and vitality

• Can reduce beer foam and flavour stability

Impact of mash in temperature on wort lipids: B.

Comparison of the fatty acid content & composition of the wort produced by the Final 65°C mashing protocol for 12 Gairdner malts

and the original 8 varieties

Modification of proteins and non-starch polysaccharides?

KI, FAN, wort -glucan, viscosity

Beer filtration (AAL and foam)

Proteins and proteases• Provision of FAN for yeast nutrition

• Some proteins impact lautering and beer filtration (gel proteins?)

• Some proteins valuable for foam stability (protein Z, LTP1 etc)

Modification of proteins and non-starch polysaccharides

Non-starch polysaccharides and viscosity

• -glucan and arabinoxylan (if large) viscosity …. Lautering filtrationcross-flow filtration!

• Source of fermentable extract (glucose)?

• Soluble fibre (size - not too big, not too small)?

varietySd

typeb-amy

%Thermb-amy

(U/g dw)a-amy

(U/g dw)LD

(U/kg dw)LD

%Thermb-glucanase (U/kg dw)

KI DP TotalProtein

Buloke Sd2H 14.7 823 251 450 55.8 523 47.6 383 10.7Gairdner Sd1 4.4 520 182 383 53.6 414 43.7 276 10.2

Buloke Sd2H 14.7 823 251 450 55.8 523 47.6 383 10.7Schooner Sd2L 0.7 350 165 318 47.4 118 48.3 184 11.0

BulokeBuloke

Microbial assessment,

the good, the bad and PYF?

Microbes - more good than bad?

• We tend to focus on the bad, PYF, taints, gushing, toxins

However!

• Will not exclude as barley and malt is not sterile

• Produce beneficial enzymes, hormones

• Some may exclude harmful microbes

• Future: DNA - PCR testing for specific taxa?Further discussion: Laitila A, More good than bad: microbes in the maltings.

Brewer & Distiller International, 2008, 4(8):52-54.

PYF• Premature yeast flocculation (PYF) is an intermittent

fermentation problem.• PYF results in incomplete wort fermentation. • PYF occurrence appears to be related to certain malt

batches. • However detection of problem batches is problematic• Is a significant problem for some breweries.

See for further:

Evans, D.E. and Kaur, M. (2009) Keeping “Sleepy” Yeast Awake Until “Bedtime”: Understanding and avoiding PYF The Brewer and Distiller International 5(5): 38-40.

The impact of PYF on fermentation

After van Nierop 2005 Thesis

TRFLP HaeIII chromatogram of suspected primary PYF malt HAEIII HAEIII

Beer clarity - haze?

Genetic solution or assistance?

Silica Eluate (SE) ImmunodetectionBarley

kDa

986450

36

30

16

6

Har

ringt

on B

arle

y

Stir

ling

Bar

ley

Lube

ron B

arle

y

Ann

abel

l Bar

ley

Pas

aden

a B

arle

y

Pre

stig

e B

arle

y

Ric

arda

Bar

ley

Cha

lice

Bar

ley

Jers

ey B

arle

y

Bris

e B

arle

y

Stir

ling

Mal

t

Uni

corn

Mal

t

Com

mer

cial

Lag

er

Uni

corn

Bee

r

Stir

ling

Bee

r

Haz

e

Haz

e

kDa

986450

36

30

16

6

kDa

986450

36

30

16

6

kDa

986450

36

30

16

6

Malt Beer Haze

Overall Classification of Varieties

SE -ve varieties

17%

SE +ve varieties

83%

SE +veExamplesAlexisArapilesBaudinDhowFranklinGairdnerManleyMetcalfeOpticScarlettSchoonerSloopSteptoeTriumph

SE -veExamplesAnnabellBarkeBowmanExcelHarringtonHaruna NijoKustaaLandlordMoravian IIIMorexPirkkaRobustSaanaUnicorn

219 varieties were screened - 181 were identified as SE +ve, while only 38 were identified as SE –ve.

Pilot Brewing Haze Stability Trial

55ºC Force Test

0

2

4

6

8

10

12

Uni

corn

Har

ringt

on

Stiri

ng

Scho

oner

Fran

klin

Gai

rdne

r

Variety

EBCHaze Units

SE (-)

SE (+)

The colloidal stability of beer produced from 6 (50L) pilot brewing trials withthe Tooheys chill haze force test (5 day 55oC/ 1 day 0oC).

Pilot brewing trial Sydney 2000 (50L)

Recent Novel Beer Haze Proteins?(Iimure et al. 2008, J. Cereal Sci. Sapporo, Japan)

Haze growth factors (proteomics approach)• Barley dimeric -amylase inhibitor (BDAI-I)• BTI-CMb• BTI-CMe

See also:Robinson, et al. (2007) Journal of Cereal Science, 45:335-342 and 343-352.

Brewer• Raw material more

predictable - consistent• Less problems - waste• Develop new products

User targets for improved malt quality specs

Maltster• Customer satisfaction• Reliability & consistency• New targets….

sustainability- reduce water use- reduce energy use

Still provide good malt!

Barley Breeder• Select specific genes• Customer satisfaction

- growers- maltsters

Co-authorsBrian Rossnagel, Alex Speers, Mike Edney,

Sophie Roumeliotis

Assistance:Very many people!

Funding:Grains Research and Development Corporation,

Grant: UT 00017.

Acknowledgments