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Q U A L I T Y I N N O V A T I O N S E R V I C E

Canadian Grain Commission, 2009

How malt quality influences sensoryproperties of beer

Dr. Michael J Edney

Research Scientist, Applied Barley Research

INNOVA 2009

Montevideo, Uruguay

September 30

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Beer drinking habits are changingBeer drinking habits are changing

Past: QuantityPast: Quantity



3/43

Beer drinking habits are changingBeer drinking habits are changing

Present: Quality and varietyPresent: Quality and variety



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Outline of presentationOutline of presentation

Review malting and malt quality

How malt quality affects visual perception of beer

Effects of malt quality on mouth-feel of beer

Malt quality factors affecting beer flavour

Safety of beer as related to malt quality



5/43

A need for maltingA need for malting

Yeasts require simple sugars

and free amino acids

Barley only has starch and

protein embedded in the

endosperm



6/43

The process of maltingThe process of malting

A Steeping

- aim for 45 % moisture

- 36 48 hours

B Germination

- adequate modification

- 96 hours

C Kilning

- dry green malt

- aroma and flavour development

- 24 hours



7/43

Laboratory analysis of malt qualityLaboratory analysis of malt quality

Simulated conditions of

first brewing phases

(mashing)

Ground malt mixed with

water, mashed at 45 and

then 70 degrees C

Resulting extract

separated and analysed



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Laboratory analysis of malt qualityLaboratory analysis of malt quality

Extract

- potential beer quantity

Soluble protein

- foam, hazes, colour

FAN free amino nitrogen

Starch-degrading enzymes

beta-Glucan (Viscosity)- filtration, hazes, mouth feel



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Ranges in malt quality dataRanges in malt quality data

< 100 ppmbeta-Glucan

> 50.0 DUalpha-Amylase

120 175 LDiastatic power

150 220 ppmFAN

4.6 5.6 %Soluble protein

80 82 %Extract

Typical Canadian levelsAnalysis



10/43

BeerBeer wide range of sensorywide range of sensory

propertiesproperties

Visual

- foam

- beer colour

- beer clarity

Mouth feel

Flavour



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Beer foam is always a concernBeer foam is always a concern

Some beer types demand

a dominant head that can

take time to pour

Other beers, notably

British ales, are known

for their lack of foam

In general adequatefoam is dependent on the

consumer and beer-type



12/43

Malt factors affecting beer foamMalt factors affecting beer foam

Promote foam:

- specific proteins (LPT1 & Z4)

- hordeins

- non-starch polysaccharides

Inhibit foam:

- lipids

- basic amino acids

- ethanol

Measurement of malt factors

- ELISA for specific proteins

- soluble protein (4.6 - 5.6 %)- malt modification



13/43

Beer colour can be quite distinctiveBeer colour can be quite distinctive

Most common beers are light

straw colour requiring special

attention to malt quality

Coloured beers require maltswith extensive colour

Colour achieved with more

intense kilning conditions

(time and temperature)

higher levels of Maillard products



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Beer colour traditionally predictedBeer colour traditionally predicted

from wort colour or soluble proteinfrom wort colour or soluble protein

Comparator with discs

Discs inconsistent and

subjective

Standard method now

relies on prediction from

absorbance of wort



15/43

Beer colours for someBeer colours for some

traditional beerstraditional beers

20-30

10-15

Amber

Ale

4-8

2-4

Straw

Light

lager

BlackGoldenColour

35-703-9ASBC Colour

units

StoutAll-malt

lager

6-18 70-140EBC Colour

units



16/43

Beer clarity can be extremelyBeer clarity can be extremely

importantimportant

Consumers demand clear lager beers

Haziness can be associated with

damaged beer

Brewers go to great lengths to produce

the required clarity



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Beer clarity is dependentBeer clarity is dependent

on a range of factorson a range of factors

Soluble protein chill haze

- interaction with polyphenols most

important

beta-Glucan

Microbial contamination

- avoided with a good HACCP



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Controlling beer hazesControlling beer hazes

Barley variety

- protein content (


19/43

Body or fullness of beerBody or fullness of beer

Dependent on processing- how

much malt in the recipe Malt quality

- starch-degrading enzymes

- degree of endosperm modification



20/43

Action of -amylase on starch

amylose

amylopectin



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Action of beta-amylase on starch

amylose

amylopectin



22/43

Action of limit dextrinase on starch

Small branched dextrins



23/43

Fermentable versusFermentable versus

unfermentable sugarsunfermentable sugars

Fermentable sugars

glucose fructose sucrose

maltose maltotriose

Unfermentable sugars

maltotetrose higher dextrins

branched dextrins

Starch-degrading enzymes (diastatic power)

alpha-amylase beta-amylase limit dextrinase



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Malt quality as related to mouth feelMalt quality as related to mouth feel

Starch-degrading enzymes decrease dextrin levels

(reduces mouth feel)

Soluble protein increases with endosperm modification

(increases mouth feel)

beta-Glucan and viscosity decrease with more

endosperm modification (reduces mouth feel)

Ethanol content increases with extract and levels of

starch-degrading enzymes



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Factors contributing to beerFactors contributing to beer

flavourflavour

Hops is the major source of flavours

- bitterness and hoppy aroma

Malt is also a direct source of flavour

- nutty/toasted/caramel flavours from Maillard

reactions during kilning

Malt also affects flavour indirectly

- yeast metabolism and supply of nutrients

Microbial contamination

Pesticides



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Higher alcohols, aldehydes andHigher alcohols, aldehydes and

estersesters wort fermentationwort fermentation

2-Phenylethanol

Acetaldehyde

Isoamyl acetate

Ethyl acetate

Decisive effect on beer

flavour

100s of these

compounds can be

found in beer

Byproducts of yeast

fermentation



27/43

Mechanisms for production of higherMechanisms for production of higher

alcohols, aldehydes and estersalcohols, aldehydes and esters

Dependent on the supply of

specific amino acids for

yeast metabolism

Supply of amino acids from

malt predicted with free

amino nitrogen (FAN)

not specific

Individual amino acids tendnot to be monitored



28/43

Free amino acids in wort:Free amino acids in wort:

UPLC analysisUPLC analysis

SampleName: ML 2007 1 B Injection: 1 Date Acquired: 7/24/2008 5:58:56 PM CDT

AMQ-

1.0

94

NH3-

1.33

2

His-

1.5

50 A

sn-

1.7

71

Ser-

2.4

11

Gln-

2.5

83

Arg-

2.6

69

Gly-

2.7

84

2.9

65 A

sp-

3.1

34

Glu-

3.7

52

4.0

34

Thr-

4.2

31

Ala-

4.6

65

GABA-4.

849

Pro-

5.3

40

Deriv

Pea

k-

6.2

53

Lys-

6.5

05

Tyr-

6.5

48

6.5

88

Me

t-

6.7

06

Va

l-

6.8

58

Ile-

7.6

25

Leu-

7.7

06

Phe-7

.809

Trp-

7.9

04

AU

-0.010

0.000

0.010

0.020

0.030

0.040

0.050

0.060

0.070

0.080

0.090

0.100

Minutes

0.00 0.50 1.00 1.50 2.00 2.50 3.00 3.50 4.00 4.50 5.00 5.50 6.00 6.50 7.00 7.50 8.00 8.50 9.00 9.50

one-week analysis time in 1960s

versus

10-minutes between injections



29/43

FAN versus the specific aminoFAN versus the specific amino

acid, valineacid, valine

Industry standards

FAN - traditional brewing > 150 ppm

- high gravity brewing > 200 ppm

Valine 130 - 140 ppm

y = 1.6154x + 25.295

R2

= 0.8781

100

140

180

220

260

300

10.0 30.0 50.0 70.0 90.0 110.0 130.0 150.0

Val (ug/ml)

FAN(mg/L)



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DiacetylDiacetyl -- butterscotchbutterscotch off flavouroff flavour

Undesirable in most lagers

Desirable in some ales

Yeasts synthesize and secrete an organic

acid which is then oxidized to diacetyl

Yeast then takes up the diacetyl and

converts it to inconsequential compounds

conversion not always complete

Diacetyl structure



31/43

Controlling and measuring diacetylControlling and measuring diacetyl

Adequate levels of valine inhibit the

yeasts synthesis of the organic acid

Yeast strain plays a role

Diacetyl levels can be reduced withlonger fermentation times (diacetyl rest)

GC with headspace analysis

Diacetyl levels in beer

0.02 0.08 ppm

Lager beer

0.06 0.30 ppm0.08 ppm

Ale beerThreshold



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Dimethylsulphide (DMS)Dimethylsulphide (DMS)

-- canned corncanned cornoff flavouroff flavour

Undesirable in most ales

Acceptable to some extent in lagers

S-methylmethionine (SMM) produced

enzymatically from methionine

Heat converts SMM to DMS (kilning, brewing)

Methionine S-methylmethionine(SMM) Dimethylsulphide(DMS)



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Avoidance and measurement of DMSAvoidance and measurement of DMS

Barley varieties can be genetically

predisposed to production of DMS

Avoided with adequate kilning and boiling

(volatile) GC with chemiluminescence

14 ppb16 27 ppb33 ppb

British aleBritish lager beerThreshold

DMS levels in beer



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TransTrans--22--nonenalnonenal

-- cardboardcardboardoff flavouroff flavour

Undesirable in all beer

Especially apparent in over-aged beer

Byproduct of malt lipids

Final oxidation occurs in the beer bottle

Triglyceride Linoleic acid hydroperoxides trans-2-nonenal

lipases lipoxygenase autoxidation



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Avoidance ofAvoidance of transtrans--22--nonenalnonenal

Lipoxygenase-free barley varieties have

recently been developed

Linolenic acid levels controlled by limiting

endosperm modification during malting

Oxidation in the bottle avoided by limiting

oxygen-uptake throughout brewing

0.10 ppb0.35 ppb0.11 ppb

Lipoxygenase-free barleyNormal barleyThreshold

Hirota et al 2006 MBAA TQ 43:131135

trans-2-nonenal levels in beer (after storage)



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Food safety and beerFood safety and beer

Food safety has become very important for

consumer acceptance even though not sensory

Examples

- Byproducts nitrosamines

- Mycotoxins and bacterial/fungal infections

- Pesticide residues



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Laboratory analysis of nitrosaminesLaboratory analysis of nitrosamines

in maltin malt

Some 30 years ago,

Nitrosamines (NDMA)

were shown to be

carcinogenic

Beer was found to be

high in NDMA, enhanced

by direct kilning

Routinely analysed in

commercial malts

customer specifications http://www.brauwesen.tu-berlin.de/


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Grain safely maintained throughGrain safely maintained through

avoidance of contaminated grainavoidance of contaminated grain

Ergot

- avoided with visual inspection

- toxins

Fusariuminfection

- avoided with ELISA testing

- mycotoxins

- gushing


C i i i id id iC i i i id id i


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Containing pesticide residues inContaining pesticide residues in

barleybarley

Restricted use of pesticides

on malt barley

Barley is routinely

monitored for residues

Specific testing required to

validate contract specifications for

minimum levels of contaminates



40/43

Summary of presentationSummary of presentation

Beer consumption is changing from quantity to

quality and as a result the importance of sensory

perception of beer has increased

Visual perception is the first and possibly most

important perception of beer (foam/colour/clarity)

closely related with malt quality

Mouth feel is also closely related to malt quality



41/43

Summary of presentation (cont.)Summary of presentation (cont.)

Beer flavour is much more subtle and is complicated

by mixtures of hop components, malt components

and a multitude of yeast metabolites

Some aspects of sensory perception of beer can be

controlled through malt quality

However, changes in processing can often

compromise other aspects of beer



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Summary of presentation (cont.)Summary of presentation (cont.)

Excess modification during malting

- less beta-glucan improves filtration and beer clarity

- more protein degradation results in poorer foam,

more hazes and excess beer colour

Higher kiln temperatures give

- reduced levels of DMS (canned corn)

- but increase beer colour and other flavours

Consumers more aware of food safety- not directly a sensory factor

- maltsters and brewers must address their concerns



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