Short tour around Hops
with HVG & AGRARIA
Carlos Ruiz
Wolnzach, June 2015
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
2
Hops in Beer
• 3 important groups of substances
– Bitter substances
– Aroma compounds
– Polyphenols
3
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.“
4
Two commercial Beers
(aprox. 20 Bitter Units)
90
(mg/l)
iso-extract
300g/hl aroma hops
80
70
60
50
IAS
nIAS
AS
PP
Others
= Iso- α-Acids
= non-iso-α-acids bitter substances
= Aroma Substances
= Polyphenols
= Glycosides, Proteins, …
40
30
20
10
0
IAS
nIAS
AS
PP
Others
5
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.“
6
Hops in Beer
Hops can….
 generate bitterness through iso-α-acids (IAA)
 define quality of bitterness through non-iso-α-acid-bittersubstances (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
 improve flavour stability
7
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
8
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
increases; scene of craft
brewers)
9
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
10
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,…
 No uniform understanding of different panels
11
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…
12
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
- Boiling time < 60 min without air/oxygen
- Hop PP are dosed in „fresh“ form to the beer
 Positive influence on beer flavour
13
Palatefullness
14
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)
• Criteria and quantity of dosage (weight, α, oil, Linalool, PP,
others)
• Time of addition (BB, MB, EB, WP, Dry Hopping…)
15
Thoughts on Hop Varieties
• The later the hop dosage, the less alternatives concerning the
selection of possible hop varieties
number
Begin of boil
Middle of boil
End of boil /WP
Dry hopping
time
• Think of alternatives or use a blend of 2 or even more
varieties. The ratio may vary according to crop results.
16
Our Vision
„Make use of hops in its natural form!“
17
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
18
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
 mainly used for dry hopping
19
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
20
German Noble Aroma Hops
α-acids
Dimension
Spalt
Tettnang
Hall. Mfr.
Hersbruck
Average
%w/w
4.1
4.1
4.1
3.1
3.9
1.3
1.3
1.3
2.4
1.6
β:α
Cohumulone
%rel.
24
24
21
20
22
Polyphenols
%w/w
5.3
5.3
4.6
4.4
4.9
1.3
1.3
1.1
1.4
1.3
ml/100g
0.60
0.60
0.85
0.75
0.70
ml/g
0.15
0.15
0.21
0.24
0.19
mg/100g
4
4
6
5
4.8
mg/g
1.0
1.0
1.5
1.6
1.3
Polyphenols:α
Total oil
Total oil:α
Linalool
Linalool:α
21
German Aroma Hops bred in Huell
Dim.
α-acids
%w/w
β:α
Perle
Tradition
Select
Saphir
Opal
Smaragd
Averg.
7.4
6.2
5.1
4.1
7.9
5.9
6.1
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
0.6
0.7
1.0
1.1
0.5
0.8
0.8
ml/100g
1.30
0.70
0.70
1.10
0.95
0.90
0.94
ml/g
0.18
0.11
0.14
0.27
0.12
0.16
0.16
mg/100g
4
7
8
10
11
10
8.3
mg/g
0.5
1.1
1.6
2.4
1.4
1.7
1.3
Polyphenols:α
Total oil
Total oil:α
Linalool
Linalool:α
22
German Bitter Hops
α-acids
Dimension
North. Brew.
Magnum
Taurus
Herkules
Average
%w/w
9.2
13.9
15.9
15.9
13.7
0.6
0.5
0.3
0.3
0.43
β:α
Cohumulone
%rel.
27
27
23
36
28
Polyphenols
%w/w
3.9
2.6
3.1
3.5
3.3
0.4
0.2
0.2
0.2
0.25
ml/100g
1.5
2.4
2.0
1.8
1.9
ml/g
0.16
0.17
0.13
0.11
0.14
mg/100g
4
8
19
8
10
mg/g
0.4
0.6
1.2
0.5
0.7
Polyphenols:α
Total oil
Total oil:α
Linalool
Linalool:α
23
Averages
α-acids
Dimension
Noble Aroma
Aroma
Bitter
%w/w
3.9
6.1
13.7
1.6
1.0
0.43
β:α
Cohumulone
%rel.
22
21
28
Polyphenols
%w/w
4.9
4.3
3.3
1.3
0.8
0.25
ml/100g
0.70
0.94
1.9
ml/g
0.19
0.16
0.14
mg/100g
4.8
8.3
10
mg/g
1.3
1.3
0.7
Polyphenols:α
Total oil
Total oil:α
Linalool
Linalool:α
24
German Special Flavor Hops
α-acids
Dimension
H. Cascade
Blanc
Melon
Mandarina
Polaris
%w/w
5.9
9.7
7.2
8.4
19.7
1.0
0.5
1.2
0.6
0.3
β:α
Cohumulone
%rel.
31
24
29
33
24
Polyphenols
%w/w
3.2
5.7
4.5
4.1
3.5
0.6
0.6
0.6
0.5
0.2
ml/100g
1.2
1.3
1.6
1.2
3.9
ml/g
0.20
0.13
0.22
0.14
0.20
mg/100g
6
6
5
7
9
mg/g
1.1
0.6
0.7
0.8
0.5
Polyphenols:α
Total oil
Total oil:α
Linalool
Linalool:α
25
Selected Aroma Substances
mg/100g
Hall. Mfr. Saphir H.
Cascade
Melon Mandarin
a
Blanc Polaris
Myrcene
173
428
720
771
833
914
2,248
βCaryophyllene
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
26
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
10
50
30-50
<2
5-10
40-50
40-60
<2
5
up to 50
up to 100
up to 5
End of boil
Whirpool
Dry hopping
•
•
•
•
BB
MB
EB/WP
Dry
Bitter hops
Aroma hops
Aroma hops
Aroma/flavor hops
 Bitterness
 Palatefullness
 Palatefullness + flavor
 individual flavor
27
28
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
gentle processes.
29
Whole Hops
• In bales: oxygen is present!
• In gas-tight foil bags: inert like pellets
• HVG produces Vakupacks= whole hops
pressed (500kg/m3): packed in foils under
vacuum; lupulin glands are crushed (better
extraction of hop oil)
30
Pellets
• Regular pellets= Type 90; yield approx. 9096kg pellets from 100 kg hops; identical with
hops
• Enriched pellets= type 45; yield approx. 4590kg pellets from 100 kg hops; alpha and oil
enriched up to a double of hops
31
Flow Chart of normal Hop Pellets
32
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,
which needs temperatures below -20°C
33
Lupulin Glands
34
Flow Chart of enriched Pellets
35
Comparison of normal and enriched Pellets
(values in %rel. to amounts of whole hops)
36
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
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
38
Carbon Dioxide Extraction
39
Flow Chart of a supercritical CO2-Extraction
40
Hop Oil Production
41
42
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
Can Hops be a Risk for Health?
 Components
 Deterioration
 Contamination with
- Plant protection substances
- Heavy metals
- Mycotoxines
- Microbiology?
Definition of "Quality"
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."
Quality = Freshness
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
 Polyphenols
Hop Quality according to the Deterioration vs.
freshly harvested Hops
Category of
Freshness / Ageing
Fresh
Slightly deteriorated
Deteriorated
Strongly deteriorated
Overaged
Loss of Alpha-acids
in % rel.
0 to 10
11 to 20
21 to 30
31 to 40
> 40
Hop Storage
Index
< 0.32
0.33 to 0.40
0.41 to 0.50
0.51 to 0.60
> 0.61
Steps of a "Quality Chain" with
conventional Hop Products

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
Drying of Hops
•
What is the "right drying temperature"?
•
Common understanding today: Tmax = 63 °C
•
Enzymatic reactions of polyphenols are unclear
•
 new findings may result in new rules
Conditioning of Hops
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
Correlation of Humidity in the Air
and the Moisture of Hops
Desired Moisture
Weight - %
Air Humidity
% relative
12
10
9
8
65
60
55
50
Packing 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
Lupulin Glands from Bales
139 kg/m3
185 kg/m3
Hop Storage Trials
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)
Summary of Storage Tests
Average changes after three month in % relative
Moderate
Storage
Good
Storage
Cold
Storage
Decrease of alpha
EBC 7.7
22
18
5
Increase of HSI
ASBC
53
43
13
Consequences
 Cold storage of hops soonest possible after the crop
 Optimal systems for an economical storage
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
Stability of weld seam
DIN 53 455
> 20 Newton
Penetration resistance
DIN 53 373
> 300 Newton
O2 in foils
several
<0.5 ml/m2/24 h/1 bar
< 0.5 vol-% O2
Physical Characteristics of Cartons
Quality criterion
Method
Example for Limits
Stackability test
EN-DIN 3037
> 17 kN/m
Penetration test
DIN 53 142
> 18 Joule
Proposed Storage Temperature for
Hops and Hop Products
Intended storage time
Whole hops
Pellets
Extracts
1 year
3 years
5 years
0 °C
- 20 °C
not practicable
10 to 15 °C
< 20 °C
5 °C
0 °C
10 °C
5 °C
Temperature in a Container "winter normal"
•
Temperature in a Container "on deck"
°C
50
45
40
35
30
25
20
15
10
5
date
0
23.2.
2.3.
10.3.
18.3.
26.3.
3.4.
Temperature in a Container "harbour"
50
°C
45
40
35
30
25
20
15
10
5
date
0
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
Temperature in a Container "disastrous"
°C
50
45
40
35
30
25
20
15
10
5
date
0
18.9.
26.9.
4.10.
12.10.
20.10.
28.10.
05.11.
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
 Timing of shipment (winter months)
or preferably the use of reefer containers
CONCLUSIONS
Damaging potential of alpha-acids (% rel.)
Pellets
conditions
Good
Extracts
conditions
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
2
15
0
2
7 to 17
50
Overseas shipment
Total
11 to 23
62
* Alpha-losses in form of yield not taken into consideration
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.
68
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.
Thank you for your attention!
71