Short tour around Hops

Short tour around Hops

with HVG & AGRARIA

Content

• Hops in Beer and as a result Motto and

Vision of HVG

• Main Hop Varieties in Germany

• Hop Products of HVG and Quality Chain

from Hops to Hop Products

Hops in Beer

• 3 important groups of substances

– Bitter substances

– Aroma compounds

– Polyphenols

Quotations from the Hop Book

– „At one extreme, hops are simply employed to add bitterness, but at the other, hop varieties are utilized in a number of ways to impart mouthfeel and aroma to beer.“

– „Even using the same technology, the sensory results obtained by different research groups will by no means be identical.“

– „The authors realized that there are no clear and simple rules pertaining to the process of hopping beer. Depending on the hopping technique, the amount of hops remaining in beer ranges from only few mg of iso-alpha-acids per liter to circa 100 mg per liter of various bitter substances and polyphenols along with more than 100 µg per liter of aroma compounds.“

10 20 30 40 50 60 70 80 90

iso-extract 300g/hl aroma hops

(mg/l)

IAS = Iso- α-Acids

nIAS = non-iso-α-acids bitter substances AS = Aroma Substances

PP = Polyphenols

Others = Glycosides, Proteins, …

Two commercial Beers

Our Motto

„

There are thus far no known hop compounds

with a negative influence on beer quality if one

excludes environmental contaminants like

pesticides, nitrates and metals. Consequently

it would not be necessary to eleminate any

hop compounds with respect to the quality of

the beer from a sensory standpoint.“

Hops can….

 generate bitterness through iso-α-acids (IAA)

 define quality of bitterness through non-iso-α-acid-bitter-substances (nIAA)

 create a diversity of hop aromatic impressions through aroma components

 create taste: palatefullness, mouthfeel, drinkability and

harmony through water-soluble substances like polyphenols, glycosides

 improve foam

Overview of sensoric Effects of Bitter

Compounds

• Accompanying (NIAA) bitter substances show a pleasant bitterness; β:α is an interesting indicator

• Polyphenolic bitter substances (Hard Resins, others) show a very pleasant bitterness

• Low cohumulon ratio is positive for quality of bitterness, foam and flavour stability

• α-acids are positive for foam and flavour stability

These effects become more evident by dosing of aroma hops in later hop additions

Hop Aroma in Beer

Estimation of the world beer market

– Not desired: more than 60%

– Indirectly desired: 20-30% (this ratio increases;

search for innovative flavour

impressions from hops)

– Directly desired: less than 10% (this ratio

Differentiation of Hop Aroma in Beer

„Kettle hop flavour“: beginning of boil (BB), seldom perceptible

„Late hop aroma“: end of boil (EB) or whirpool (WP); goal is a perceptible hopnote

(„Hopfenblume“)

„Dry hop aroma“: Dry-hopping into the cold beer, hop aroma is linked to a specific variety

Descriptors of Hop Aroma

There exist different proposals, f.i.

• Beer aroma wheel, many examples

• Descriptors according properties like flowery, fruity, citrussy, hoppy, herbal, woody…

• Descriptors according comparison like:

Apple, Orange, Grapefruit, Vanilla, Melon, Lemon, Mandarin, Ananas, Passion Fruit,…

What are Polyphenols (PP)?

• Secondary Metabolites like bitter and aroma components

• ~ 5000 known in the world of plants, many of them have a positive reputation (health benefits) as e.g. antioxidants and radical scavengers…

Hop Polyphenols and Beer Taste

Prejudice:

- „PP are responsible for a tannic bitterness“

>50 years ago:

- Hops stored in air resulted in oxidized and polymerized PP - Longer boiling time (>120 min.) with contact to oxygen

Today:

- Hops are stored in cold warehouses - Hops and pellets are packed inert

Main variable Parameters for Hopping

• Hop varieties (n > 100) • Growing conditions

– Country, region

– Harvest time (colour, max α, max oil?)

• Handling of cone hops (temperature, density, oxygen?) • Hop product

• Whole hops (inert packaging!) • Pellets / Extract

• „Advanced“ Products (Iso, Aroma)

Thoughts on Hop Varieties

• The later the hop dosage, the less alternatives concerning the selection of possible hop varieties

• Think of alternatives or use a blend of 2 or even more

time Begin of boil Middle of boil End of boil /WP Dry hopping nu mbe r

Our Vision

Hop Varieties

Official groups: aroma & bitter

Defining aroma and bitter varieties



No clear differentiation possible according chemical

composition



More oriented on application; bitter hops provide

beer bitterness; aroma hops fulfill additionally other

purposes



Expectations: bitter hops > 10% α, strong aroma;

aroma hops < 10% α, mild aroma, high polyphenol

content

Additional (inofficial) groups

• Dual-purpose hops (f.i. Chinook, Centennial)

• Noble (aroma) hops = land races (f.i.

Tettnang, Spalt, Hersbruck, Hallertau

Mittelfrueh, Saaz)

• Hops with special flavor = special flavor hops

= flavor hops = hops with unique flavor

Characterisation of hop varieties

• Agronomic characteristics: yield, resitance to

deseases…

• Chemical compounds (examples): α-acids, β:α,

cohumulone-ratio, polyphenols, polyphenols:α,

total oil, total oil:α, linalool, linalool:α

German Noble Aroma Hops

Dimension Spalt Tettnang Hall. Mfr. Hersbruck Average

α-acids %w/w 4.1 4.1 4.1 3.1 3.9 β:α 1.3 1.3 1.3 2.4 1.6 Cohumulone %rel. 24 24 21 20 22 Polyphenols %w/w 5.3 5.3 4.6 4.4 4.9 Polyphenols:α 1.3 1.3 1.1 1.4 1.3 Total oil ml/100g 0.60 0.60 0.85 0.75 0.70 Total oil:α ml/g 0.15 0.15 0.21 0.24 0.19 Linalool mg/100g 4 4 6 5 4.8 Linalool:α mg/g 1.0 1.0 1.5 1.6 1.3

German Aroma Hops bred in Huell

Dim. Perle Tradition Select Saphir Opal Smaragd Averg.

α-acids %w/w 7.4 6.2 5.1 4.1 7.9 5.9 6.1 β:α 0.7 0.8 1.0 1.9 0.8 0.9 1.0 Cohumulone %rel. 30 26 23 15 15 15 21 Polyphenols %w/w 4.1 4.3 4.9 4.5 3.7 4.5 4.3 Polyphenols:α 0.6 0.7 1.0 1.1 0.5 0.8 0.8 Total oil ml/100g 1.30 0.70 0.70 1.10 0.95 0.90 0.94 Total oil:α ml/g 0.18 0.11 0.14 0.27 0.12 0.16 0.16 Linalool mg/100g 4 7 8 10 11 10 8.3 Linalool:α mg/g 0.5 1.1 1.6 2.4 1.4 1.7 1.3

German Bitter Hops

Dimension North. Brew. Magnum Taurus Herkules Average

α-acids %w/w 9.2 13.9 15.9 15.9 13.7 β:α 0.6 0.5 0.3 0.3 0.43 Cohumulone %rel. 27 27 23 36 28 Polyphenols %w/w 3.9 2.6 3.1 3.5 3.3 Polyphenols:α 0.4 0.2 0.2 0.2 0.25 Total oil ml/100g 1.5 2.4 2.0 1.8 1.9 Total oil:α ml/g 0.16 0.17 0.13 0.11 0.14 Linalool mg/100g 4 8 19 8 10 Linalool:α mg/g 0.4 0.6 1.2 0.5 0.7

Averages

Dimension Noble Aroma Aroma Bitter

α-acids %w/w 3.9 6.1 13.7 β:α 1.6 1.0 0.43 Cohumulone %rel. 22 21 28 Polyphenols %w/w 4.9 4.3 3.3 Polyphenols:α 1.3 0.8 0.25 Total oil ml/100g 0.70 0.94 1.9 Total oil:α ml/g 0.19 0.16 0.14 Linalool mg/100g 4.8 8.3 10 Linalool:α mg/g 1.3 1.3 0.7

German Special Flavor Hops

Dimension H. Cascade Blanc Melon Mandarina Polaris

α-acids %w/w 5.9 9.7 7.2 8.4 19.7 β:α 1.0 0.5 1.2 0.6 0.3 Cohumulone %rel. 31 24 29 33 24 Polyphenols %w/w 3.2 5.7 4.5 4.1 3.5 Polyphenols:α 0.6 0.6 0.6 0.5 0.2 Total oil ml/100g 1.2 1.3 1.6 1.2 3.9 Total oil:α ml/g 0.20 0.13 0.22 0.14 0.20 Linalool mg/100g 6 6 5 7 9 Linalool:α mg/g 1.1 0.6 0.7 0.8 0.5

Selected Aroma Substances

mg/100g

Hall. Mfr. Saphir H. Cascade Melon Mandarin a Blanc Polaris Myrcene 173 428 720 771 833 914 2,248 β-Caryophyllene 76 48 48 25 46 52 278 Humulene 273 113 134 25 143 145 739 α- + β-Selinene 10 25 14 193 113 218 27 Linalool 6 9 6 5 7 6 9 Geraniol 1 1 7 8 14 2 4 Geranylacetate 0 0 15 1 1 8 17 Sum of 9 Esters 11 13 36 106 87 89 359

Hop Dosing Regime (yield in %rel.)

α-acids Polyphenols Esters/Alc. Terpenes

Begin of boil 40-50 50-60 0 0 Middle of boil 15-25 50 5 0 End of boil 10 50 30-50 <2 Whirpool 5-10 40-50 40-60 <2 Dry hopping 5 up to 50 up to 100 up to 5

• BB Bitter hops  Bitterness

• MB Aroma hops  Palatefullness

• EB/WP Aroma hops  Palatefullness + flavor

Conventional Hop Products

Problems with whole hops – Logistic – Heterogenity – Stability – Automatic dosing – Yields – Wort clarification

Conventional hop products should overcome the disadvantages of whole hops without chemical changes of substances by

Whole Hops

• In bales: oxygen is present!

• In gas-tight foil bags: inert like pellets

• HVG produces Vakupacks= whole hops

pressed (500kg/m

3

): packed in foils under

vacuum; lupulin glands are crushed (better

extraction of hop oil)

Pellets

• Regular pellets= Type 90; yield approx.

90-96kg pellets from 100 kg hops; identical with

hops

• Enriched pellets= type 45; yield approx.

45-90kg pellets from 100 kg hops; alpha and oil

enriched up to a double of hops

Background of enriched Pellets

• Seperation of lupulin glands from leafs (waste)

• Grinding and seaving are only possible with hard lupulin glands • The liquid phase of resin and oil in the lupulin must be hard,

Comparison of normal and enriched Pellets

Sensitive Steps during the Pellet Production

Product Temperature Exposure Time

Kilning < 60 °C < 30 min Grinding < 20 °C few seconds

Sieving for Type 45 < -30 °C -

Mixing powder < 20 °C < 120 min Pelletiziation < 55 °C few seconds

Packing in Foils

• Oxygen-diffusion of the foil material:

< 0.5 ml/m² * 24h * 1bar

• More than 95% of all packed foils

less than 1% v/v Oxygen

The Quality Chain from Hops to Hop Products

Definition of “Quality Chain“:

• All processes from hops untill dosage in the brew house are parts of the quality chain

• Goal of an optimal quality chain is the best possible identity of all components between the harvest at hop and ist dosage in form of a hop product



Components



Deterioration



Contamination with

- Plant protection substances

- Heavy metals

- Mycotoxines

- Microbiology?

Definition is being done normally according to Variety and Growing area

Definition in this case:

"Quality defines the degree of deterioration of the hop

components from the harvest until the dosing into the wort."

Definition of "Quality"

Analytical indices such as alpha degradation or Hop Storage Index (HSI) describe only partial aspects.

All important hop components suffer through deterioration

 Bitter substances

 Aroma substances



Hop Quality according to the Deterioration vs.

freshly harvested Hops

Category of Loss of Alpha-acids Hop Storage Freshness / Ageing in % rel. Index

Fresh 0 to 10 < 0.32 Slightly deteriorated 11 to 20 0.33 to 0.40 Deteriorated 21 to 30 0.41 to 0.50 Strongly deteriorated 31 to 40 0.51 to 0.60 Overaged > 40 > 0.61

 Hop harvest with picking, drying, conditioning, baling

 Storage in form of cone hops

 Processing to hop products

 Storage of hop products

 Transport to the brewery

 Storage and dosing in the brewery

Steps of a "Quality Chain" with

conventional Hop Products

• What is the "right drying temperature"?

• Common understanding today: T_max = 63 °C

• Enzymatic reactions of polyphenols are unclear •  new findings may result in new rules

Goal is the homogenisation of the moisture within the cones.

 2 - 3 hours conditioning with circulating air

 Afterwards blending of outside and inside air according to desired water content

• Air temperature of approx. 18 °C

Desired Moisture Air Humidity Weight - % % relative 12 65 10 60 9 55 8 50

Correlation of Humidity in the Air

and the Moisture of Hops

Goal: Optimal logistics with minimal damaging of the lupulin membrane

 Better storage stability through limited

oxidation protection of the lupulin membrane

 Requirement for lupulin enriched pellets

(Type 45) are intact lupulin glands

Packing of Hops

Lupulin Glands from Bales

139 kg/m

3

185 kg/m

3

12 varieties were stored in 3 types of storage:

- Moderate storage ( 5 to 30 °C)

- Good storage ( 5 to 20 °C)

- Cold storage ( 1 to 5 °C)

Average changes after three month in % relative

Moderate Good Cold Storage Storage Storage

Decrease of alpha 22 18 5

Increase of HSI 53 43 13

Summary of Storage Tests

Consequences

 Cold storage of hops soonest possible after the crop

Improvement of Hop Products

 Logistic

 Homogeneity

 Stability

 Dosing in the brew house

Hop production means to overcome the disadvantages of cone hops without damaging components.

Sensitive Steps during the Pellet Production

Product Temperature Exposure Time

Kilning < 60 °C < 30 min

Grinding < 20 °C few seconds

Sieving for Type 45 < -30 °C -

Mixing powder < 20 °C < 120 min Pelletiziation < 55 °C few seconds Pellet cooling < 18 °C < 20 min

Physical Characteristics of Pellet Foils

Quality criterion Method Example for Limits Diffusion of oxygen DIN 53 380 <0.5 ml/m2/24 h/1 bar

Stability of weld seam DIN 53 455 > 20 Newton Penetration resistance DIN 53 373 > 300 Newton O₂ in foils several < 0.5 vol-% O₂

Physical Characteristics of Cartons

Quality criterion Method Example for Limits

Stackability test EN-DIN 3037 > 17 kN/m

Proposed Storage Temperature for

Hops and Hop Products

1 year 3 years 5 years

Whole hops 0 °C - 20 °C not practicable

Pellets 10 to 15 °C 5 °C 0 °C Extracts < 20 °C 10 °C 5 °C

Temperature in a Container "winter normal"

Temperature in a Container "on deck"

0 5 10 15 20 25 30 35 40 45 50 23.2. 2.3. 10.3. 18.3. 26.3. 3.4. date °C

Temperature in a Container "harbour"

0 5 10 15 20 25 30 35 40 45 50 15.7. 6:07 23.7. 6:07 31.7. 6:07 8.8. 6:07 16.8. 6:07 24.8. 6:07 1.9. 6:07 date °C

Temperature in a Container "disastrous"

0 5 10 15 20 25 30 35 40 45 50 date °C

Consequences during Pellet Transport

 With an intact foil only inert reactions occur; Alpha-losses 2 - 15 % relative;

unpleasant aroma substances will be formed

 Formation of gas

 pressure increases  foil gets a hole

Gas escapes and air penetrates

 Oxidation up to total loss

Pellets Extracts conditions conditions

Good Moderate Good Moderate

Kilning + conditioning 3 to 5 10 3 to 5 10

Storage of whole Hops 3 to 8 30 3 to 8 30

Production* 0 to 2 5 0 to 2 5

Storage for 1 year 3 to 6 12 1 to 2 3

Overseas shipment 2 15 0 2

CONCLUSIONS

Think of strategic Stocks

You as a brewer have developed a beer with a special recipe and defined hops. In a short crop, these hops are very expensive or not even

available.

Properly packed hops or pellets (O₂-free) stored at approx. 0°C keep quality for several years. Be more independent of bad (and expensive) crops, especially in the case of aroma hops with special character.

A product, some years old, produced from a good crop is better than a product of a current bad crop.

A simple rule: good crops in quantity are normally combined with high quality and often with low spot prices for some varieties.

Summary (1)

 "Quality" is the degree of freshness

independent of the growing area and the hop variety.

 A degradation of bitter acids, aroma components and polyphenols from the time of harvest to the point of hop addition to the kettle is defined as ageing.

 There are analytical methods (ageing indicators like HSI), but further research is necessary.

Summary (2)

"Quality chain" comprises all processes from

harvest to the dosage into the wort.

Farmer, Processor and Brewer are partners

in the quality chain. They are responsible to

prevent damages of hop components.