123rd MBAA Anniversary Convention

Fresh Beer, Fresh IdeasMBAA – New England

January 2014

Alastair PringlePringle –Scott LLC

Objective and Outline

• Objective– Identify practical solutions for keeping beer as fresh

as possible.

• Outline– Background – What is freshness? – Reactions in brewhouse, fermentation, & finishing – Practical steps to freshness improvement– Making decisions on freshness

2

Background - Factors that Affect Beer Shelf Life • Microbiological spoilage – Bacteria: lactic acid, diacetyl, H2S, etc – Yeast: over-attenuation, over carbonation–

• Physical stability – Chill-haze– Permanent haze

• Flavor stability – Changes in flavor

3This talk will focus on flavor stability

Background - Why Worry About Flavor Stability?

• Customers want a consistent flavor

• They accept consistent flavor, even if it includes off-flavors– e.g. DMS, oxidation, light-struck

• They reject variable flavors – Beer will not meet their expectations– Do not like surprises

4

Freshness in the Marketplace • Wide freshness variation – confuses the customer

• Narrow range – customer gets a consistent product

5

Fre

quen

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Stale Fresh

Fre

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Stale Fresh

WHAT IS FRESHNESS?

6

Freshness

• Freshness is how close a product is to when it was : – Picked from the field – Made in the bakery or

brewery

• Implied:– Better taste– Better nutrition – No artificial preservatives

7

Changes in Beer • Freshness begins to decline once beer is

packaged• The decline is accelerated by increased

temperature

8

0 50 100 150 200 250 3004

4.55

5.56

6.57

7.58

8.59

Days

80oF

70oF

36oF

Less

Fre

sh

Why Does Beer Lose Freshness?

9

Sulfite

Cardboard

Paper

Ester

Bitter

Harsh

Sweet

Staling is the sum of many flavor changes:- no single compound or mechanism is responsible- there is no single solution

Inte

nsity

Time

Where Should You focus? • Across the entire system

10

Brewery Wholesaler Retailer

Brewhouse Fermentation Finishing Packaging

We will first look at the brewing process

BREWHOUSE

11

First, a Word about Carbonyls • A class of compounds that contain a C=O group

C=O

• Include:– long-chain unsaturated aldehydes.• 1969 - trans-2-nonenal was shown to impart a stale,

cardboard, flavor when added to beer.– other volatile carbonyls: • ketones, esters

12

A

B

Brewhouse Chemistry - Mashing and Lautering -

13

Unsat. Fatty Acids

Carbonyls

Lipase

Polyphenols

Tannins

O2

Lipoxygenase

Malt polyphenols Malt LipidsMalt Protein

Amino Acids

Protease

Oxygen is important in carbonyl production

Brewhouse Chemistry- Boiling -

14

Polyphenols

Carbonyls

O2

Iso-alpha acids

Extraction

Isomerization

Tannins + Protein

Carbonyl-protein

Wort protein

From Mashing

Maillard Products

Unsat. Fatty Acids

Heat

Amino acids

Hops Sugar

Copper

Vessels & coils

Oxygen and heat drive complex reactions

Malt Tannins

FERMENTATION

15

Fermentation Chemistry

16

Carbonyls

Alcohols

Protein– carbonyl

SO2

SO2– carbonyl

Sulfate

H+

Yeast

Ethanol

Sugars

SO2

SO2 is an important anti-oxidant, especially in lagersCarbonyls become bound to protein and SO2

Iron

Yeast

Iron

Uptake

Autolysis

FINISHING AND PACKAGING

17

Finishing and Packaging Chemistry

18

Iron

Reactive Oxygen Species O2

- superoxide anion HOO- perhydroxyl radical

H2O2 hydrogen peroxide

HO. hydroxyl radical

OxygenFilter medium

Chemistry in the Package- reactions involving oxygen-

Oxygen

Reactive Oxygen Species

Finished Beer

Package

Iron & Copper

Sulfur Dioxide

Iso-alpha acids

Sulfate

Sweet, fruity• e.g. Ethyl

isovalerate

Side chain

Polyphenols Harsh, astringent• tannins

+

Others reactions – oxidation of ethanol and higher alcohols

Ethanol

Diagram courtesy of Grace Darex Packaging Technologies

ingressD.O.

Chemistry in the Package-reactions independent of oxygen-

20

SO2– carbonyl

Protein – carbonyl

Carbonyl +

Maillard Products +

Paper, cardboard• e.g. Trans-2-

nonenal Solvent • e.g. furfuryl ethyl

ether

SO2

Other reactions – esterification, etherification, glycoside hydrolysis, & ester hydrolysis

Ethanol

These compounds, which developed in the brewhouse,result in stale flavors in the package

The Brewing Process - factors that are important for freshness -

• Yeast– SO2

21

Brewhouse Fermentation Finishing Packaging

• Oxygen • Metal ions

• Oxygen• Heat

• Oxygen

PRACTICAL STEPS TO FRESHNESS IMPROVEMENT

22

How can Freshness be improved?

• Maximal freshness can only be achieved by making improvements across the entire production chain– Chain is as good as its weakest link – Do not only focus on one area

23

Brewery Wholesaler Retailer

Brewhouse Freshness Best PracticesMashing

24

Bottom entry

Fore masher

Course grind Malt

No scorching or build-up No votex upon emptying

Water Effective mixing that minimizes foam and

creates no vortex

Pump seals maintained to

avoid air pick-up

Minimize exposure to air

Brewhouse Freshness Best Practices- Lautering -

25

Bottom mash entry

Side mash entry

Minimal Foam

Not exposing the

grain bed

or

Minimize exposure to air

Brewhouse Freshness Best Practices – Boiling -

26

Gentle fill minimizing foam

Avoid extended boil time

Efficient heat transfer – minimal scorching

No vortex during emptying Pump seals

maintained to avoid air pick-up

Avoid boil temperatures above 212 F

Minimize air and heat

Vigorous boil

Brewhouse Freshness Best Practices- Whirlpool-

27

Tangential flow

Minimal foam on wort surface

Pump seals maintained to

avoid air pick-up

Gentle wort flow

Avoid excess time

Minimize air and heat exposure

Fermentation Best Practices • Increase SO2 levels in lagers– SO2 is an antioxidant– below level requiring labeling

• Minimize yeast autolysis – Can release iron into beer.

28

Fermentor

Yeast

Maturation

Increase SO2 Reduce autolysis

Lower ferm. temp X

Lower aeration rate X

Lower pitch rate X

Increase yeast food X X

Lower maturation temp. X

Reduce maturation time X

Finishing Best Practices

29

De-oxygenate adjustment water

Filter Beer Tank

Water Filter

Gas with CO2

before filling

Use low iron D.E.

Chiller

Buffer

Chill-proofer

Maintain to avoid oxygen

pick up

Seals maintained to avoid air pick-up

De-oxygenate water

Minimize air and iron pickup

PACKAGING

30

Packaging Freshness Best Practices• Minimize oxygen – Finished beer D.O. should be low (50 ppb or less)– Bottles

• Evacuation• CO2 flushing • Proper adjustment of jetters

– Cans • Use CO2 flushing • Bubble breakers • Under-cover gassing with CO2

31

Measuring Package Oxygen • Shake-out method – fair – Better than not measuring oxygen – Detects very high levels – Too inaccurate to be used for driving

down oxygen levels • Dissolved oxygen – better – Pierce package and run beer through a

DO meter. – Detects beer DO levels - but not

headspace oxygen• Total package oxygen - best – Oxygen in beer + headspace oxygen – Semi-automatic 32

Packaging Materials Best Practices • Many more times the oxygen may

enter the package over its shelf-life as is present immediately after packaging

33

Package Type Source of oxygen ingress Improve freshness through:

Glass Bottle • Crown • Barrier crown - better• Absorbing crown – best

Plastic Bottle • Closure

• Bottle

• Barrier crown – better • Absorbing crown – best

• Oxygen barrier – nylon • Absorbing technology – e.g. Co

Can • Minimal ingress

Diagram courtesy of Grace Darex Packaging Technologies

DISTRIBUTION

34

0 50 100 150 200 250 3004

4.55

5.56

6.57

7.58

8.59

Days

Distribution Chain Control- It all about Time and Temperature -

• Higher temperature leads to a rapid loss of freshness – 2 to 4 times more for every 18oF

(10oC)– Beer stored at 80o F for 50 days

will be as fresh as beer stored at 70oF for 100 days

• Draft beer that is kept cold will remain fresher than packaged

35

40oF

80oF 70oF

Keeping beer cool and for shorter times means beer is consumed fresher

– local production and distribution helps

Less

Fre

sh

MAKING FRESHNESS DECISIONS

36Photo courtesy of PureMalt

Tools to Assess the Process• Process assessment – Visual:

• Vortexing • Excessive foam in brewery vessels• Scorching on heat exchange

surfaces

– Measurement • Excessive levels of dissolved

oxygen where you have clear liquid– Lauter– Wort receiver– Kettle knock out 37

Freshness Measurement • Focus on a reliable measure related to the consumer

experience. – Sensory is the best measure– Avoid complex chemical analyses– Measurement of radicals is mainly related to SO2 and or iron level

• Develop a Freshness Panel– Train using in-house or outside expertise (FlavorActiv)– Develop a scale: e.g. 1 to 10

• Use the panel to provide feedback on experiments and process improvement efforts– Does a process change improve freshness?– Is the cost worth it?– What is the shelf-life of a beer? 38

Beer Shelf-Life Determination

39

0 50 100 150 200 250 3004

4.55

5.56

6.57

7.58

8.59

Days

70 F

32 F

Less

Fre

sh

Shelf-life is the time before the beer tastes unacceptably different from fresh beer

X

Summary

• Freshness of beer in the marketplace is affected by:– Production methods from the brewhouse to the

finished package– Storage conditions after the beer is packaged

• The freshness of beer that reaches the consumer can be enhanced by systematically improving each link in the chain as much as practically possible

40

Brewery Wholesaler Retailer

The Art of Beer

41

Pri

ngle

-Sco

tt.co

m

Questions?