Brewing the Future: Oregon State University

How Craft Beer is Transforming the Way We Think About Hops & Hop FlavorThomas H. Shellhammer

Oregon State University

Department of Food Science and Technology

The elements of this talk

• What is craft beer?

• How has craft beer affected the brewing supply chain

• Hop-forward beers are changing how we evaluate hop flavor

• Non-volatile components increase in number and complexity

• Controlling hop aroma – the new holy grail.

Principle Components Concentration (%w/w)

Cellulose-lignins 40.0 - 50.0

Protein 15.0

Alpha acids 2.0 - 17.0

Beta acids 2.0 - 10.0

Water 8.0 - 12.0

Minerals 8.0

Polyphenols and tannins 3.0 - 6.0

Lipids and fatty acids 1.0 - 5.0

Hop oil 0.5 - 3.0

Monosaccharides 2.0

Pectins 2.0

Amino acids 0.1

European Brewery Convention Hops and Hop Products, Manual of Good Practice;

Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.

Chemical Composition of Hops

Global beer and hops production

Barth Haas Report 2014

Traditional view of global hops supply vs demand

Barth Haas Report 2014

What is craft beer?

Market segments as defined by the Brewers Association

Microbreweries• Brew less than 15,000 BBL per year

Brewpub• Restaurant-brewery with >25% of beer sold on site

Regional brewery• 15,000 – 6 Million BBL per year

Regional Craft Brewery• A regional brewery producing >50% all malt beer or adjuncts used to

enhance and not lighten flavor.

Craft Beer• “Small” – less than 6 million BBl

• Independent (at least 75% independently owned)

• Traditional

U.S. Brewing – Large vs small brewers

0

20000000

40000000

60000000

80000000

100000000

120000000

ABI MillerCoors Yuengling Boston BeerCo.

Sierra NevadaBrewing Co.

New BelgiumBrewing Co.

Gambrinus LagunitasBrewing Co.

DeschutesBrewery

An

nu

al U

.S. P

rod

uct

ion

(U

S B

bl)

U.S. Brewing – Large vs small brewers

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

Boston Beer Co. Sierra NevadaBrewing Co.


Gambrinus Lagunitas BrewingCo.

Deschutes Brewery

An

nu

al U

S P

rod

uct

ion

(U

S B

bl)

http://www.brewersassociation.org/statistics/number-of-breweries/

Number of breweries, 1870 – PresentTremendous growth in U.S. as a result of craft brewery startups

Brewpubs/Microbreweries drive growth of craft

http://www.brewersassociation.org/statistics/number-of-breweries/

https://www.brewersassociation.org/statistics/national-beer-sales-production-data/

Long term trends in craft brewing

Chuck Skypeck, Brewers Association

U.S. craft beer growth, 2001 - 2013

Chris Swersey, Brewers Association

Craft beer is growing…but overall U.S. beer growth is flat


U.S. Craft brewers are using more and more hops

Adapted from Brewers Association

400

450

500

550

600

650

700

750

2008 2010 2012 2014 2016

Ho

p u

sag

e (

g/h

L)

Year

Hop usage (g/hL)



0

100

200

300

400

500

600

700

800

2008 2010 2012 2014 2016

Ho

p u

sag

e (

g/h

L)

Year

Hop usage (g/hL)



0

1000

2000

3000

4000

5000

6000

7000

8000

9000

2008 2010 2012 2014 2016

Ho

p u

sag

e (

g/h

L)

Year

Hop usage (g/hL)

How is this growth impacting farming?

U.S. aroma hop acreage has increased significantly


-50%

0%

50%

100%

150%

200%

250%

% Acreage Change '12-'13: Craft Hops vs CTZ

Where is growth in U.S. hop varieties?

U.S. farmers are investing and growing

How does the growth in demand impact breeding?

Hops breeding takes time and enormous effort

Year 1: Parental selection and crossing

• Based on breeding objectives

Year 2: Early selection

• Start 40,000

• 10% selection rate

• End 4000

Years 3,4,5: Intermediate selection

• Start 4,000


• End 40

Years 6,7,8:Advanced selection

• Start 40


• End 1.2

Years 9,10,11:Elite Trials

• Overall rate: 0.005%

• Start 2

• Selection rate: ?

Year 11+: Commercialization

Jason Perrault, Select Botanicals Group

Hop Breeding Objectives Moving Towards Aroma

Alpha/Bitter

Processed hops.

Yield measured in Kg. Alpha/acre

Typically high alpha varieties, increasingly aroma.

AromaMinimal processing.Yield measured in lb/acreTypically aroma varieties, some high alphas.

Brewers’ flavor expectations of hop varietiesPCA of responses – D1 vs. D2

Cascade

Citra

Amarillo

Simcoe®

Summit

Chinook

Nelson Sauvin

(CTZ) Columbus/Tomahawk/Ze

us

Ahtanum

Herkules

Hallertau Taurus

Millenium

Styrian Golding

Apollo

Nugget

Galena

Palisade® Willamette

Perle (US origin)

Northern Brewer

Spalt Select Hallertau Tradition

Tettnanger

Brewer's Gold

Hallertau MittleFreuh

Saaz

Perle (German origin)

East Kent Golding

Magnum

Cluster

Spalter

Fuggle

Floral

FruityTropical fruit

CitrusHerbal

Spicy

GrassyWoody

Onion/Garlic

Musty

LeatherTobacco

-2

-1

0

1

2

3

4

5

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

D2 (

20.8

6 %

)

D1 (32.90 %)

Biplot (axes D1 and D2: 53.76 %)after Varimax rotation

Nels

on

Sa

uvin

Am

arillo

Ca

sca

de

Citra

Ah

tan

um

Pa

lisa

de

®

Will

am

ette

He

rku

les

Sim

co

e®

Ch

ino

ok

Halle

rta

u T

au

rus

Pe

rle

(U

S o

rigin

)

Halle

rta

u T

rad

itio

n

Pe

rle

(G

erm

an

origin

)

Halle

rta

u M

ittle

Fre

uh

Sp

alt S

ele

ct

Te

ttn

an

ge

r

Sty

ria

n G

old

ing

Sa

az

Su

mm

it

CT

Z

Ap

ollo

Mill

en

ium

Ea

st K

en

t G

old

ing

Fu

ggle

Sp

alte

r

Ma

gn

um

Clu

ste

r

Ga

len

a

Bre

we

r's G

old

Nugge

t

No

rth

ern

Bre

we

r

0

20

40

60

80

100

120

Dis

sim

ila

rity

Cluster analysis yields 4 groups

Group characteristics and varieties

Group Floral FruityTropical

fruit Citrus Herbal Spicy Grassy WoodyOnion/Gar

lic Musty Leather Tobacco

1 2.847 3.292 2.843 3.653 1.673 1.766 1.298 0.526 0.461 0.252 0.200 0.183

2 2.565 1.881 1.128 1.933 2.622 2.461 1.825 1.245 0.696 0.416 0.388 0.418

3 2.078 2.112 1.918 2.665 2.138 2.199 2.011 1.417 2.769 1.237 0.489 0.503

4 2.063 1.480 0.725 1.391 2.280 2.147 1.891 1.513 0.637 0.779 0.633 0.604

Group 1 Group 2 Group 3 Group 4Citrus Herbal Grassy WoodyFruity Spicy Onion TobaccoFloral Floral Musty Leather

Cascade Simcoe® Summit Millennium Citra Chinook CTZ Nugget

Amarillo Ahtanum Apollo Galena

Nelson Sauvin Herkules Northern Brewer Hallertau Taurus Brewer's Gold

Styrian Golding East Kent Golding Palisade® Magnum

Willamette Cluster

Perle (US origin) Spalter

Spalt Select Fuggle

Hallertau Tradition

Tettnanger Hallertau MittleFreuh

Saaz Perle (German origin)

Brewers’ flavor expectations of hop varietiesPCA of responses – D1 vs. D2

Cascade

Citra

Amarillo

Simcoe®

Summit

Chinook

Nelson Sauvin

(CTZ) Columbus/Tomahawk/Ze

us

Ahtanum

Herkules

Hallertau Taurus

Millenium

Styrian Golding

Apollo

Nugget

Galena

Palisade® Willamette

Perle (US origin)

Northern Brewer

Spalt Select Hallertau Tradition

Tettnanger

Brewer's Gold

Hallertau MittleFreuh

Saaz

Perle (German origin)

East Kent Golding

Magnum

Cluster

Spalter

Fuggle

Floral

Fruity

Tropical fruitCitrusHerbal

Spicy

GrassyWoody

Onion/Garlic

Musty

LeatherTobacco

-2

-1

0

1

2

3

4

5

-6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6

D2 (

20.8

6 %

)

D1 (32.90 %)

Biplot (axes D1 and D2: 53.76 %)after Varimax rotation

-50%

0%

50%

100%

150%

200%

250%

% Acreage Change '12-'13: Craft Hops vs CTZ

Where is growth in U.S. hop varieties?

How does the growth craft beer impact how we think about and measure hop flavor?

Hop-forward beers are created using late and dry hopping and unique varieties

CC

V

Kettle Whirlpool

• Factors

• Hopping Regime (Kettle, Whirlpool, Dry-hop)

• Hop Cultivar (Simcoe, Hallertau Mittlefrueh)

• Yeast (ale vs lager)

• Response

• Chemical (Volatiles)

• Sensory (Descriptive Analysis)

60 minute boil ~100 °C, 10

min18°C, 48 hours

Daniel Sharp, 2014

Hopping regime and hop variety interact

Daniel Sharp, 2014

Craft brewers’ top brands are hop-forward

0

500,000

1,000,000

1,500,000

2,000,000

2,500,000

Boston Beer Co. Sierra NevadaBrewing Co.


Gambrinus Lagunitas BrewingCo.

Deschutes Brewery

An

nu

al U

S P

rod

uct

ion

(U

S B

bl)

Principle Components Concentration (%w/w)

Cellulose-lignins 40.0 - 50.0

Protein 15.0

Alpha acids 2.0 - 17.0

Beta acids 2.0 - 10.0

Water 8.0 - 12.0

Minerals 8.0

Polyphenols and tannins 3.0 - 6.0

Lipids and fatty acids 1.0 - 5.0

Hop oil 0.5 - 3.0

Monosaccharides 2.0

Pectins 2.0

Amino acids 0.1

European Brewery Convention Hops and Hop Products, Manual of Good Practice;

Getranke - Fachverlag Hans Carl: Nurnberg, Germany, 1997.

Chemical Composition of Hops

Thermal isomerization of alpha acids produces iso-alpha acid bitterness

Low solubility

Low bitterness

High solubility

High bitterness

Iso-a acids

Before HPLC there was counter current extraction or separation

Link

https://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0ahUKEwj4rKrYs57MAhUiyYMKHTgjDEwQjRwIBw&url=http://www.chem.uoa.gr/applets/AppletCraig/Appl_Craig2.html&bvm=bv.119745492,d.amc&psig=AFQjCNGD9VQYRvbC-Q

Counter current extraction

Liquid-Liquid extraction of bitter compounds from beer

Strong Acid

Adds excess hydrogen ions to solution – protonating all carboxylic acid functional

groups

3 N Hydrochloric Acid

Non-Polar SolventWhen functional groups are

protonated at a lower pH molecules decrease in polarity

2,2,4 trimethylpentane

+

BeerBitter compounds

Iso alpha acidsOxidized hop acids

PolyphenolsNon-bitter compounds

Alpha acids

+

The IBU Analysis

Measure the absorbance at 275 nm

Absorbance @275 x 50 = Bittering Units

1 BU ≠ 1 ppm iso-alpha acid

The IBU Analysis

BU correlates with bitterness and iso-alpha acids concentrations at low hopping levels

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

Bit

tern

ess

Un

its

Iso-alpha acids (ppm) via HPLC

Correlation between total IAA & IBU

Lightly kettle hopped beer

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

16.0

0.0 2.0 4.0 6.0 8.0 10.0 12.0 14.0

Sen

sory

Bit

tern

ess

Bit

tern

ess

Un

its


Sensory bitterness tracks BU/IAA

y = 1.2x + 2.0R² = 0.906

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

Bit

tern

ess

Un

its


Correlation between total IAA & IBU @ higher levels

y = 1.2x + 2.0R² = 0.906

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

Bit

tern

ess

Un

its


Correlation between total IAA & IBU

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0.0

10.0

20.0

30.0

40.0

50.0

60.0

70.0

80.0

90.0

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

Sen

sory

Bit

tern

ess

Bit

tern

ess

Un

its


Sensory bitterness does not track BU/IAA

Heavily dry-hopped beer

a b c

de

f

g

h

i

j

a. (+)-catechin

b. (-)-epicatechin

c. (-)-epigallocatechin

d. Procyanidin B3

e. Prodelphinidin B3

f. Procyanidin C2

g. quercetin

h. kaempferol

i. xanthohumol

j. isoxanthohumol

Another potential source of bitterness – hop polyphenols

Extraordinarily diverse group of

compounds found in all plant material.

Characterized by a number of aromatic

rings with numerous substituted

hydroxyl

groups.

Polyphenols are highly reactive,

easily oxidized and polymerized

into high MW tannins.

a and b acid oxidation

a acid - Humulone b acid - LupuloneIso-a-acid

iso humulone


Oxidized alpha acid

Humulinone

Oxidized beta acid

Hulupone

a acid - Humulone b acid - Lupulone

Oxidation

Iso-a-acid

iso humulone


Oxidized alpha acid

Humulinone

Oxidized beta acid

Hulupone

a acid - Humulone b acid - Lupulone

Oxidation

Iso-a-acid

iso humulone

Algazzali, 2014

10 Lagers

4 Amber-Reds

4 Pale Ales

4 IPAs

5 of 10

humulinones

4 of 4

4 of 4

4 of 4

hulupones

0 of 10

2 of 4

2 of 4

3 of 4

17 7

Commercial beer survey

22

Algazzali, 2014

Commercial beer survey

humulinonesaverage (mg/L)

huluponesaverage (mg/L)

Lagers (10) 1.3 (0 - 4.4) 0.0

Amber/Red (4) 14.4 (1.7 - 39.9) 2.0 (0 - 6.8)

Pale Ale (4) 8.2 (3.0 - 12.9) 0.8 (0 - 1.7)

IPA (4)20.7 (11.7 -

27.9)

1.8 (11.7 -

27.9)

Algazzali, 2014

62.5

21.6

39.9

6.8

0

10

20

30

40

50

60

70

BU iso-α-acid(ppm)

humulinone(ppm)

hulupone(ppm)

Example: Amber-Red 2

Algazzali, 2014

62.5

21.626.0

5.6

0

10

20

30

40

50

60

70

BU iso-α-acid(bitterness)

humulinone(bitterness)

hulupone(bitterness)

41%49%

10%

Example: Amber-Red 2

Algazzali, 2014

With hop forward beers…

Does controlling aroma matter?

How does a brewer control aroma intensity or quality?

Does total hop oil content matter?

Conceptual approach – does oil amount matter

Primary Factors:

• Oil Content (15 unique oil contents)

• Oil Composition

Secondary Factors:

• Region (Washington, Oregon)

• Location (WA – 2) (OR – 2)

• Farm (WA – 3) (OR – 2)

• Harvest Dates (Aug 14 – Sept 22)

• Kiln Type, Time, Temperature

R2

C1

1 lb/barrel

ControlWhole Cone Cascade

OregonWashington

Farm 1 Farm 2 Farm 1 Farm 2

1 2 3 n

Farm 3

Vollmer, 2015

Cascade Hops with varying total oil content

0.0

0.5

1.0

1.5

2.0

2.52

27

2_1

22

92

_1

30

00

_1

30

00

_2

24

34

_1

23

97

_1

24

71

_1

30

08

_1

23

80

_1

23

16

_1

26

05

_1

30

34

_1

24

18

_1

22

95

_1

24

32

_1

23

56

_1

24

06

_1

25

80

_1

26

10

_1

26

34

_1

33

05

_1

33

05

_2

24

14

_1

26

78

_1

30

56

_2

31

28

_1

31

28

_2

30

56

_1

Tota

l Oil

Co

nte

nt

(ml/

10

0g)

Lot ID

OSU Total Oil Content

Vollmer, 2015

Cascade Hops with varying total oil content

5.00

6.00

7.00

8.00

9.00

10.00

0.0

0.5

1.0

1.5

2.0

2.5

22

72

_1

22

92

_1

30

00

_1

30

00

_2

24

34

_1

23

97

_1

24

71

_1

30

08

_1

23

80

_1

23

16

_1

26

05

_1

30

34

_1

24

18

_1

22

95

_1

24

32

_1

23

56

_1

24

06

_1

25

80

_1

26

10

_1

26

34

_1

33

05

_1

33

05

_2

24

14

_1

26

78

_1

30

56

_2

31

28

_1

31

28

_2

30

56

_1

Ove

rall

Ho

p A

rom

a In

ten

sity

Tota

l Oil

Co

nte

nt

(ml/

10

0g)

Lot ID

OSU Total Oil Content OHAI

Vollmer, 2015

The “usual suspects” may not matter

Vollmer, 2015

y = 74.3x + 235.3R² = 0.031

0

200

400

600

800

1000

1200

1400

1600

1800

5 6 7 8 9 10

mg/

10

0g

of

ho

ps

OHAI

Myrcene

y = -0.46x + 10.737R² = 0.019

0

2

4

6

8

10

12

14

16

5 6 7 8 9 10

OHAI

Linalool

Conclusion

• Beware of brewing dogma

• Challenge conventional wisdom with science

• Adapt

Acknowledgements

Victor Algazzali

Jeff Clawson

Daniel Sharp

Dan Vollmer

Philip Wietstock

Brewing the Future: Oregon State University

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