Keep It Fresh:Keep It Fresh:U d t di H Ti T t U d t di H Ti T t Understanding How Time, Temperature Understanding How Time, Temperature

and Oxygen Impact Your Beer, and What and Oxygen Impact Your Beer, and What

To Do About ThemTo Do About Them

A member outreach initiative of the Brewers Association Technical

CommitteeCommittee

I. The Basics of Flavor Stability I. The Basics of Flavor Stability --yyDr. Charlie Bamforth, Anheuser-Busch Endowed Professor of Malting & Brewing Sciences, UC DavisDavis

II. Quality Points:II. Quality Points: CO2 Purging; Metals CO2 Purging; Metals Q yQ y g g;g g;and Radicals; Crown Liners; Sensory and Radicals; Crown Liners; Sensory --Tom Nielsen, Senior Research Analyst, Sierra Nevada Brewing Co.

III. III. Practical Methods For Maintaining Practical Methods For Maintaining ggFreshness Freshness --Mitch Steele, Head Brewer/Production Manager, Stone Brewing Co.

Flavor Stability: The BasicsFlavor Stability: The Basics

Charlie Bamforth

(After Dalgliesh)

Aim: to achieve what the customer Aim: to achieve what the customer expectsexpectsexpectsexpects

This may not be what the brewer is This may not be what the brewer is led to believe is best

Chemical Changes In Beer…Chemical Changes In Beer…gg

•New flavorsome products from i i i b reactions occurring in beer

•Disappearance of flavorsome materials b reactions occ rring in beer by reactions occurring in beer

•Completion of reactions that started upstreamupstream

•Release of flavorsome components from bindingfrom binding

•Unmasking of flavorsome components by removal of components that by removal of components that disguise them

The matrix is critical The matrix is critical –– changes The matrix is critical The matrix is critical –– changes

will always be more perceptible

in a beer of “gentler” flavor

600600--700 700 Volatile Components Volatile Components in in BeerBeer

Staling Contributors?

AcetaldehydeFurfural( ) d(E)-β-damascenone2-aminoacetophenone2 methylpropanal2-methylpropanal2-methylbutanal3-methylbutanal3 methylbutanal4-methyl-4-mercaptopentan-2-one(E-2-nonenal)

etc, etc

Many of these compounds have very low Many of these compounds have very low flavor thresholdsflavor thresholdsflavor thresholdsflavor thresholds

e.g. E-2-nonenal 0.1 ppb

Flavor Changes That Can Flavor Changes That Can ggOccur in BeerOccur in Beer

Decline in bitterness• Decline in bitterness• Increase in harsh• Decrease in fruity/estery/floral• Increase in ribes• Increase in wet paper/cardboard• Increase in breadyIncrease in bready• Increase in sweet/toffee/honey• Increase in metallic

Increase in earthy• Increase in earthy• Increase in straw• Increase in woody• Increase in wine/sherry

Grainy??

The The Carbonyl GroupCarbonyl Group

C OC O

UnsaturatedUnsaturatedUnsaturatedUnsaturatedFatty AcidsFatty Acids

Bitter Bitter AcidsAcidsBitter Bitter AcidsAcids

CarbonylsCarbonylsAmino Amino AcidsAcids

Higher AlcoholsHigher AlcoholsHigher AlcoholsHigher Alcohols

Reactive Oxygen Species (R.O.S.)Reactive Oxygen Species (R.O.S.)

Addition of electrons

hydroxyl (OH•)Increasedreactivity

perhydroxyl peroxideH+

superoxide (O2•)H

oxygen

IronCopperCopper

Unsaturated fatty acidsy

tauto-oxidation

lipoxygenase

HydroperoxidesHydroperoxides

Staling carbonylsStaling carbonylse.g. E-2-nonenal

Carbonyl + SO2 Adducty 2

Carbonyl + -NH2 Adduct

EquilibriaCompetition

Carbonyl + binding agent ↔ complex

yeasty

Alcohol

Yeast has a lot of carbonyls to deal with

Generic solutions:Generic solutions:

attend to parameters which lessen attend to parameters which lessen the development the development across the across the boardboardpp

- oxygenoxygen- temperature- SO2?SO2?

Arrhenius: Arrhenius:

rate of reaction at (t+10)oC

2 3 rate of reaction at t oC= 2-3 x rate of reaction at t oC

800

600

700ha

ract

er

RefrigeratorRefrigerator

500

600ct

age

d ch

s) “Cl i ”

300

400

lop

dist

inc

(day

s “Classic” room temperature

100

200

e to

dev

el

Davis summer

0

00

0 10 20 30 40 50 60

Tim

Temperature (deg C)

Typical Typical Way Way of of Reporting Flavor DataReporting Flavor Data

0 1 2 3 4 5

Fr h t lFresh stale

Typical Typical Way Way of of Reporting Flavor DataReporting Flavor Data

0 1 2 3 4 5

Fr h St lControl (no added precautions): 3.7

Fresh Stale

Trial (added precautions): 3.1

Staling CompoundsStaling Compounds

Beforeprecautionsprecautions

Stabilizer protocol Bp

Stabilizer protocol A

Level atwhich

timewhichflavorchange isgdetectedAssess

1

Assess 2

Electron Electron Spin ResonanceSpin Resonance

interaction of unpaired electrons with magnetic fields - i e detects radicalsmagnetic fields - i.e. detects radicals

120 ESR

100

ng a

s 80

of s

talin

d by

esr

40

60

essi

on o

ndic

ated

20supp

re in

00 2 4 6 8 10

Sulfite in beer (ppm)

Anon

EyeballsEyeballs!!

Quality Points: CO2 Purging; Quality Points: CO2 Purging; Quality Points: CO2 Purging; Quality Points: CO2 Purging; Metals and Radicals; Crown Metals and Radicals; Crown

Li SLi SLiners; SensoryLiners; Sensory

Tom Nielsen

CARBON DIOXIDE PURGING CARBON DIOXIDE PURGING OF BEER LINES AND VESSELSOF BEER LINES AND VESSELSOF BEER LINES AND VESSELSOF BEER LINES AND VESSELS

Teledyne 3110xl: Trace OTeledyne 3110xl: Trace O22 in COin CO22

• ~$2,500 per unit

• ~$300 / per fuel• ~$300 / per fuel cell– Lasts 6 monthsasts 6 o t s

Teledyne 3110xl: Trace OTeledyne 3110xl: Trace O22 in COin CO22

•Measures down to 0.1 ppm O2 in CO2 with proper calibration of A2-CXL sensor

•O2 gas sniffers, like Gastech, only go down to 1000 ppm of O2 in CO2down to 1000 ppm of O2 in CO2

Teledyne 3110xl in actionTeledyne 3110xl in action

850800

1000

luen

t

CO2 Purging Empty 100 gallon Vessel – 1 scfm

500400

300400

600

800

purg

e ef

fl

300210

14075 40 24 20 18 17 15

0

200

400

ppm

O2

in

00 60 120 180 240 300 360 420 480

p

Minutes of Purging Thomas P. Nielsen- 2010

IRON, COPPER & FREE IRON, COPPER & FREE RADICAL FORMATIONRADICAL FORMATIONRADICAL FORMATIONRADICAL FORMATION

Iron and ESR/EPRIron and ESR/EPRFi 4

160

Relationship Between Potential Free Radical Activity as Measured by EPR and Iron Levels in Beer

Figure 4

1086 46 64580100120140

alue

y = 1086x + 46.645R² = 0.7935

20406080

T-12

0 Va

020

0.000 0.020 0.040 0.060 0.080 0.100 0.120Fe (ppm)

PassivationPassivation of New Stainlessof New Stainless

•Kegs

•Tanks

•Manufacturer does not completely passivateTanks

•Lines

•Other

p y p

•Chromium oxide layer

•Citric Acid pH 3-4 for a Other stainless equipment

pfew weeks

•Works better at hotter q ptemps

•Metallic taste above 40 ppb Iron for supertasters

BOTTLE CROWN LINERSBOTTLE CROWN LINERS

Bottle Crown Liners: Bottle Crown Liners: Oxygen IngressOxygen Ingress

Bottle Crown Liners: Bottle Crown Liners: Oxygen IngressOxygen Ingress

• Pick your crown liner based on how much O2 control you have in your b lbottling operation;

• If routinely experience high package• If routinely experience high package airs in bottles, then a scavenger liner will provide some immediateliner will provide some immediate protection to your beer.

Bottle Crown LinersBottle Crown LinersBottle Crown LinersBottle Crown Liners

•PVC and non-PVC based liners

•Oxygen scavengers available for bothOxygen scavengers available for both

•Oxygen barriers in non-pvc formula

Th l it f th li t i l ill •The polarity of the liner material will dictate which compounds are preferentially scalpedpreferentially scalped

– Hydrophobic formulas = hop oils

– Hydrophillic formulas = estersHydrophillic formulas = esters

Crown Liner SpecsCrown Liner SpecsCrown Liner SpecsCrown Liner Specs

•OTR = Oxygen Transmission Rate– How permeable the liner is to

oxygen

– Supplier should provide this number

•Hardness– Hardness above a shore D value of

46-47 will be problematic due to high incidence of leakers

Bottle Crown Liners: Bottle Crown Liners: Aroma ScalpingAroma ScalpingAroma ScalpingAroma Scalping

Aroma ScalpingAroma ScalpingAroma ScalpingAroma Scalping

Aroma ScalpingAroma ScalpingAroma ScalpingAroma Scalping

Aroma ScalpingAroma ScalpingAroma ScalpingAroma Scalping

AgitationAgitationAgitationAgitation

GRAPEFRUIT OR CATTY???GRAPEFRUIT OR CATTY???

My Experience with “My Experience with “RibesRibes” ” My Experience with My Experience with RibesRibes FlavorFlavor

•Fresh flavor associated with the following hops:– Simcoe–Citra–ChinookChinook–Others

•4-MMP (4-methyl-2-mercapto pentanone)4 MMP (4 methyl 2 mercapto pentanone)

•Very unstable compound in both beer and hopsand hops

AGED AROMA: MEATY AGED AROMA: MEATY BROTHY COMPLEXBROTHY COMPLEXBROTHY COMPLEXBROTHY COMPLEX

Aged Aroma : Meaty Aged Aroma : Meaty BrothyBrothyComplexComplexComplexComplex

•Methional

•MethionolMethionol

•Methyl Mercaptan

3 M th l f f l thi l•3-Methyl furfuryl thiol

AGED AROMA: SHERRY WINE/ AGED AROMA: SHERRY WINE/ STALE FRUIT COMPLEXSTALE FRUIT COMPLEXSTALE FRUIT COMPLEXSTALE FRUIT COMPLEX

Aged Aroma : Sherry Wine/ Aged Aroma : Sherry Wine/ Stale Fruit ComplexStale Fruit ComplexStale Fruit ComplexStale Fruit Complex

•Vanillin

•Beta Damascenone

•Phenylacetaldehydee y aceta de yde

•Diacetyl

•Trans 2 nonenal•Trans-2-nonenal

•Furfuryl ethyl ether

– A whole gang of substituted furans

Aged Aroma : Sherry Wine / Aged Aroma : Sherry Wine / Stale Fruit ComplexStale Fruit Complex

Analyte=ethyl-3-methylbutyrate

0 0090.01

0.011

Bivariate Fit of Corrected Response By Day

y y y y

0 0050.0060.0070.0080.009

ted

Res

pons

e

0 0010.0020.0030.0040.005

Cor

rect

0.0010 50 100 150 200

Day

Linear Fit

Increase in ethyl-3-methylbutyrate over 180 days at room temperature

Aged Aroma : Sherry Wine / Aged Aroma : Sherry Wine / Stale Fruit ComplexStale Fruit Complex

Thomas P. Nielsen -2010

SENSORY ANALYSISSENSORY ANALYSIS

CascadeCascade

Fl l

3

6Floral

Fruity

S iO i / li

Overall hop aroma

0

3 Spicy

PineyWoodsy

Onion/garlicGerman MagnumCascade FreshCascade 2 month

CitrusCheesy

Cascade 2 month

HerbalGrassy

P ti l M th d F P ti l M th d F Practical Methods For Practical Methods For Maintaining FreshnessMaintaining Freshnessgg

Mitch Steele

GOOD BREWING PRACTICESGOOD BREWING PRACTICESL ki b ki i i !•Leaking beer out = sucking air in!

•Keep clamps tight•Replace bad/leaking pump seals•Replace bad/leaking pump seals•Regular Audits of all processes and

practices•Reaction plans for when things aren’t

right•Education!•Education!

– Do your brewers and packaging team “get it”?– Does your sales team understand?

Do the people that deliver your beer understand?– Do the people that deliver your beer understand?– Difference between oxidized and skunky.

DO METERSDO METERS

•Great tool!

•Check all beer post fermentation-filter, bright tank, bottled beer (with piercing device)

•Allows setting of specifications and d l i i ldeveloping reaction plans

BREWHOUSE CHECKSBREWHOUSE CHECKS• In General:• In General:

– Foam = bad– Treat mash and wort (everything hot) “gently”– Minimize “hot time”

• Mash Vessel: – Excessive agitation-not only bad for malt, but can result in excessive

oxidation

• Lauter Tun:– Don’t expose grain bed

• Boil:– Excessive foaming– Watch boil temperatures Too high could enhance carbonyl Watch boil temperatures. Too high could enhance carbonyl

formation

• Whirlpool:– Check whirlpool foam, especially if you have a separate whirlpool– Set a standard Increases in foaming can be caused by a bad pump Set a standard. Increases in foaming can be caused by a bad pump

seal or a valve issue– Cool wort quickly

STONE BREWHOUSE QUALITY AUDITBrand

Order #Batch #Batch #

DATEExpectation and reason As Found

PROCESSMASH IN: Malt KettleCleanliness before mash in Should be empty of all liquid and grain, vessel should be cleanCleanliness before mash in Should be empty of all liquid and grain, vessel should be clean

Malt mash in time Mashing Summary ReportAgitation During Mash In-Any vortexing, foam at top of mash?

List the agitator speed. Vortexing of the water/mash, and foaming are bad, either indicates oxidation.

Temperature at mash in complete

Is it at set point?

Any malt balls, malt clumps? Indicates quality of mixing

MASH KETTLE OPERATION

Time required to get to conversion temperature (after pumpback complete)

Mashing Summary Report

Any mash vortexing after Indication of oxidationy gmash in-during high speed agitation?Conversion time Does it match the recipe?Raise to mash off time Does it match the recipe?Mash off agitation-is there any Indication of oxidationvortexing, are we pulling air at the end of the process?Time at mash off temperature Any delays are badMash off time Mashing Summary Report

CELLAR CHECKSCELLAR CHECKSf f•After fermentation, keep tanks in

CO2 atmosphere–Watch downtubes

–Check pressure on fermenters

dd d d•Adding Ingredients or dry-hopping–Risky operation

•Headspace gas purity tester–Based on CO2 reaction with caustic soda

FILTRATION CHECKSFILTRATION CHECKS

•High Risk Area for Oxidation

•Patrol/Audit for:– Leaks

– Pump seals

– Proper purging of hoses, lines and vessels

•Check DO on filtered beer regularly

•DE Filters-purge dosing tank or enclose to keep oxygen free

D l R ti Pl•Develop a Reaction Plan

Filter DO3-9 ppb 10-50 ppb (after 10 min of filtering) 51 + ppb

↓ ↓ ↓↓ ↓ ↓↓ ↓ ↓

If DO does check all hoses, clamps,

gaskets for tightness and l ki b

not drop after filtering 30 bbls then move on to 51 + ppb

i t ti

Put filter in recirc and

f ll 10 50

no reactionCheck BBT

DOCheck FV

DO

Check DO with

another meter ↔

leaking beer; adjust if needed

instructions and notify supervisor

follow 10-50 ppb

instructions

BBT DOBBT DO3-9 ppb 10 + ppb 30 + ppb

↓ Check DO with another meter and follow instructions below↓

↓ ↓ ↓

Place BBT on HOLD

Bubble C02 f b tt

Place BBT on HOLD

d tifno reaction

from bottom of BBT until DO is equal to or below 9

ppb

and notify supervisor follow 10 +

ppb instructions

PACKAGING CHECKSPACKAGING CHECKSh k ’ l k•Check DO’s or Total Package Air

regularly through packaging runsH t d d ti l f hi h DO–Have a standard reaction plan for high DO

•Pumps

Cl h d fi i•Clamps, hoses and fittings

•Filler valves

•Check cap crimps

•Fob levels

•Bottle conditioning

Hi DO, greater than 20 ppb detected on bottle.

HIGH DODO--BOTTLEDBOTTLED BEER--REACTION PLAN

Shut down bottling and check the

Verify Calibration of the D&O NO Calibrate Meter

check the following:

meter, by hanging on bright tanks

Check meter on BBTCheck meter on BBT before starting up line again

Check that DO on BBT W t k

If DO higher than 20,

YES

NOBBT Was taken before bottling, and recheck to verify less than 20 ppb

bubble tank with CO2 and get DO low before starting back up

NO

YES

Check The following:1. All Tri-Clamps, including bottom of BBT.2. Pump Seal

YES

u p Sea3. FOB water DO4.Check impact of kegging operation

DEVELOP DATE CODE DEVELOP DATE CODE SYSTEMSYSTEMSYSTEMSYSTEM

• Critically important for maintaining fresh beer in the market

• Requires significant commitment

• To develop reasonable code dates:

– Keep a museum of package beer

– Store at room temperature (not chilled)

– Taste over course of several weeks/months and Taste over course of several weeks/months and determine the point at which beer becomes non-representative of the brand

– Repeat exercise frequently to ensure freshness is – Repeat exercise frequently to ensure freshness is not changing

TRAINING WITH BREWING TEAMTRAINING WITH BREWING TEAM

• Fresh vs Oxidized Beer: taste often and use taste results to verify code dating program.

C i l l di f d i• Continual, regular audits of process and practices

• Constant reinforcement

• Stop production if DO or TPO levels are high• Stop production if DO or TPO levels are high

• DO Meter maintenance and cleaning

• Explain the following:Explain the following:– Bottle conditioning is not a substitute for good brewing

practices that prevent oxygen ingress!

– Neither is bubbling CO2 through a tank with high DONeither is bubbling CO2 through a tank with high DO.

– Prevention is the best cure!

TRAINING WITH FIELD TEAMTRAINING WITH FIELD TEAM

d d h “b l d ”•Use code dates, either a “bottled on” or “best before”/”enjoy by”

•Explain to team how code dates are derived and why. Demonstrations are best!best!

– Package beer in clear glass and expose to sunlight compare with fresh beer and beer sunlight, compare with fresh beer and beer past code date

•Be diligentBe diligent

•Forward customer complaints to them

CHECK MARKET BEERCHECK MARKET BEER

•Don’t rely solely on beer stored at the brewery to verify flavor and aging brewery to verify flavor and aging potential.

•Buy beer from stores on a regular Buy beer from stores on a regular basis

•Check both draft and packaged beersCheck both draft and packaged beers

•Verify date coding and explain to retailers retailers

Q & AQ & A

Thank You to Our Presenters:Charlie Bamforth

Tom NielsenTom NielsenMitch Steele

This presentation, including an audio transcript and complete Q&A, p g p pwill be available soon in the Power Hour archive of the Members-

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