Upload
lada
View
63
Download
0
Tags:
Embed Size (px)
DESCRIPTION
123rd MBAA Anniversary Convention. Fresh Beer, Fresh Ideas MBAA – New England January 2014. Alastair Pringle P ringle – S cott LLC. Objective and Outline . Objective Identify practical solutions for keeping beer as fresh as possible. Outline Background What is freshness? - PowerPoint PPT Presentation
Citation preview
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
Freq
uenc
y
Stale Fresh
Freq
uenc
y
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 Le
ss F
resh
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
Prin
gle-
Scot
t.com
Questions?