Fresh Beer, Fresh Ideas

Transcription

1 123rd MBAA Anniversary Convention Fresh Beer, Fresh Ideas Alastair Pringle Pringle Scott LLC

2 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

3 Background - Factors that Affect Beer Shelf Life Microbiological spoilage Bacteria: lactic acid, diacetyl, H 2 S, etc Yeast: over- attenuation, over carbonation Physical stability Chill-haze Permanent haze Flavor stability Changes in flavor This talk will focus on flavor stability 3

4 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

5 Frequency Frequency Freshness in the Marketplace Wide freshness variation confuses the customer Fresh Stale Narrow range customer gets a consistent product Fresh Stale 5

6 WHAT IS FRESHNESS? 6

7 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

8 Less Fresh Changes in Beer Freshness begins to decline once beer is packaged The decline is accelerated by increased temperature o F o F 70 o F Days 8

9 Intensity Why Does Beer Lose Freshness? Time Staling is the sum of many flavor changes: - no single compound or mechanism is responsible - there is no single solution 9

10 Where Should You focus? Across the entire system Brewery Wholesaler Retailer Brewhouse Fermentation Finishing Packaging We will first look at the brewing process 10

11 BREWHOUSE 11

12 First, a Word about Carbonyls A class of compounds that contain a C=O group A B C=O Include: long-chain unsaturated aldehydes trans-2-nonenal was shown to impart a stale, cardboard, flavor when added to beer. other volatile carbonyls: ketones, esters 12

13 Brewhouse Chemistry - Mashing and Lautering - Malt Protein Malt Lipids Malt polyphenols Protease Lipase Unsat. Fatty Acids O 2 Polyphenols Lipoxygenase Amino Acids Carbonyls Tannins Oxygen is important in carbonyl production 13

14 Brewhouse Chemistry - Boiling - Unsat. Fatty Acids Hops Sugar Amino acids From Mashing Carbonyls O 2 Wort protein Polyphenols Malt Tannins Extraction Isomerization Heat Vessels & coils Carbonyl-protein Tannins + Protein Iso-alpha acids Maillard Products Oxygen and heat drive complex reactions Copper 14

15 FERMENTATION 15

16 Fermentation Chemistry Yeast Carbonyls Sulfate SO 2 Sugars Iron Uptake Yeast Autolysis H + Alcohols Protein carbonyl SO 2 carbonyl SO 2 Ethanol Iron SO 2 is an important anti-oxidant, especially in lagers Carbonyls become bound to protein and SO 2 16

17 FINISHING AND PACKAGING 17

18 Finishing and Packaging Chemistry Filter medium Oxygen Iron Reactive Oxygen Species O 2 - superoxide anion HOO - perhydroxyl radical H 2 O 2 hydrogen peroxide HO. hydroxyl radical 18

19 Finished Beer Iron & Copper Chemistry in the Package - reactions involving oxygen- D.O. Oxygen ingress Reactive Oxygen Species Package Sulfur Dioxide Polyphenols Iso-alpha acids Side chain + Ethanol Sulfate Harsh, astringent tannins Sweet, fruity e.g. Ethyl isovalerate Others reactions oxidation of ethanol and higher alcohols Diagram courtesy of Grace Darex Packaging Technologies

20 Chemistry in the Package -reactions independent of oxygen- SO 2 carbonyl Protein carbonyl Carbonyl + SO 2 Paper, cardboard e.g. Trans-2-nonenal Maillard Products + Ethanol Solvent e.g. furfuryl ethyl ether Other reactions esterification, etherification, glycoside hydrolysis, & ester hydrolysis These compounds, which originated in the brewhouse, result in stale flavors in the package 20

21 The Brewing Process -factors that are important for freshness- Brewhouse Fermentation Finishing Packaging Oxygen Yeast Oxygen Oxygen Heat SO 2 O 2 uptake Metal ions 21

22 PRACTICAL STEPS TO FRESHNESS IMPROVEMENT 22

23 How can Freshness be improved? Brewery Wholesaler Retailer Maximal freshness can only be achieved by making improvements across the entire production chain Chain is as good as its weakest link Recommend that you do not only focus on one area 23

24 Brewhouse Freshness Best Practices Mashing Effective mixing that minimizes foam and creates no vortex No scorching or build-up Water Malt Fore masher Bottom entry Course grind No votex upon emptying Pump seals maintained to avoid air pick-up Minimize exposure to air 24

25 Brewhouse Freshness Best Practices - Lautering - Not exposing the grain bed Minimal Foam Side mash entry or Bottom mash entry Minimize exposure to air 25

26 Brewhouse Freshness Best Practices Boiling - Vigorous boil Avoid boil temperatures above 212 F Avoid extended boil time Efficient heat transfer minimal scorching Gentle fill minimizing foam No vortex during emptying Minimize air and heat Pump seals maintained to avoid air pick-up 26

27 Brewhouse Freshness Best Practices - Whirlpool- Tangential flow Minimal foam on wort surface Gentle wort flow Avoid excess time Pump seals maintained to avoid air pick-up Minimize air and heat exposure 27

28 Fermentation Best Practices Yeast Fermentor Increase SO 2 levels in lagers SO 2 is an antioxidant below level requiring labeling Minimize yeast autolysis Can release iron into beer. Increase SO 2 Reduce autolysis Maturation Lower ferm. temp Lower aeration rate Lower pitch rate X X X Increase yeast food X X Lower maturation temp. Reduce maturation time X X 28

29 Finishing Best Practices De-oxygenate adjustment water Water Filter Use low iron D.E. Buffer Gas with CO 2 before filling Chillproofer De-oxygenate water Filter Beer Tank Chiller Maintain to avoid oxygen pick up Seals maintained to avoid air pick-up Minimize air and iron pickup 29

30 PACKAGING 30

31 Packaging Freshness Best Practices Minimize oxygen Finished beer D.O. should be low (50 ppb) Bottles Evacation CO 2 flushing Proper adjustment of jetters Cans Use CO 2 flushing Bubble breakers Under-cover gassing with CO 2 31

32 Measuring Package Oxygen Shake-out method fair Better than not measuring oxygen Detects high levels Too inaccurate to be used for driving down oxygen levels Dissolved oxygen better Pierce package and run beer through a D.O. meter. Detects beer D.O. levels - but not headspace oxygen Total package oxygen - best Oxygen in beer + headspace oxygen Semi-automatic 32

33 Packaging Materials Best Practices Many more times the oxygen may enter the package over its shelf-life as is present immediately after packaging Package Type Source of oxygen ingress Improve freshness through: Glass Bottle Crown Barrier crown - better Absorbing crown best Plastic Bottle Closure Barrier crown better Absorbing crown best Can Bottle Minimal ingress Oxygen barrier nylon Absorbing technology e.g. Co 33 Diagram courtesy of Grace Darex Packaging Technologies

34 DISTRIBUTION 34

35 Less Fresh 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 18 o F (10 o C) Beer stored at 80 o F for 50 days will be as fresh as beer stored at 70 o F for 100 days Draft beer that is kept cold will remain fresher than packaged o F 80 o F 70 o F Days Keeping beer cool and for shorter times means beer is consumed fresher local production and distribution helps 35

36 MAKING FRESHNESS DECISIONS Photo courtesy of PureMalt 36

37 Tools to Assess the Process Process assessment Visual: Vortexing Excessive foam in brewery vessels Scorching on heat exchange surfaces Measurement Excess levels of dissolved oxygen where you have clear liquid Lauter Wort receiver Kettle knock out 37

38 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 SO 2 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

39 Less Fresh Beer Shelf-Life Determination Days 32 F 70 F Shelf-life is the time before the beer tastes unacceptably different from fresh beer X 39

40 Summary Brewery Wholesaler Retailer 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