1. Brewing Ingredients Symposium
for
The British Guild of Beer Writers
Hops & Hop Products
Trevor Roberts
28th February 2012

2. Hops & Hop Products
Influences of hops on beer quality
Introduction to the full range of hop products
Different ways of hopping & flavour differentiation
The cost of hops in beer
Questions

3. The case for Hops & Hop Products
The objective....
... to convince you that hops are THE brewing raw
material that open up many opportunities for the
brewer whilst at the same time representing
excellent value for money!!

4. Hops & Hop Products
Influences of hops on beer quality
Introduction to the full range of hop products
Different ways of hopping & flavour differentiation
The cost of hops in beer
Questions

5. Typical Analysis
of Hops (after Stevens)
Resins 15%
Proteins 15%
Monosaccharides 2%
Polyphenols 4%
Pectins 2%
Volatile Oils 0.5%
Ash 8%
Moisture 10%
Cellulose etc. 43%

6. Typical Analysis
of Hops (after Stevens)
Resins 15%
Proteins 15%
Monosaccharides 2%
Polyphenols 4%
Pectins 2%
Volatile Oils 0.5%
Ash 8%
Moisture 10%
Cellulose etc. 43%

7. Lupulin Glands

8. Why Use Hops?
Precipitation
Bitterness
of proteins
Biological
Aroma
Stability
Foam Anti-Oxidant

9. Why Use Hops – Hop Resins?
(principally the alpha- and beta-acids)
Precipitation
Bitterness
of proteins
Biological
Aroma
Stability
Foam Anti-Oxidant

10. Hop Resins - Bitterness
• Principal hop resins are the alpha acids (non-bitter
taste) – converted to iso-alpha-acids (bitter taste)
when boiled with the wort by the process of
Isomerisation
• Alpha acids not very soluble in wort but iso-alpha-
acids more soluble; however the efficiency of
conversion and dissolution in wort is poor - only
about 45-55%
• Iso-alpha-acids readily stripped out by absorption
onto yeast, protein and filters; final efficiency in beer
is only around 30-35% (when using traditional hopping
methods)

11. Hop Resins – Contribution to Formation
of Beer Foam
• Hydrophobicity – Iso-alpha-acids show a
tendency to readily come out of solution
• Ability to bind proteins – readily form
complexes with polypeptides from the beer
• Iso-alpha-acid/Polypeptide complexes –
provide structural strength to the film layer around the
bubbles; helps prevent foam collapse

12. Hop Resins – Contribution to
Foam Lacing
• Beer slowly drains from foam
• Iso-alpha-acid/Polypeptide complexes get
stronger - left behind on surface of glass
• >10 mgs/l iso-alpha acids (10 BU’s) required
to achieve lacing; >20 mgs/l for optimum effect

13. Hop Resins – Biological Stability
• Use of hops in brewing dates back to medieval
times
• Introduced into Europe in the 11th century
• In due course consequent benefits realised by
brewers:
- able to brew in the summer months
- beers could be shipped long distances
without spoilage (IPA to India)

14. Hop Resins – Biological Stability
• Alpha acids, beta acids and iso-alpha-acids - all
demonstrate antibacterial activity
• Disrupt transport systems across bacterial cell
membranes
• Known to suppress the development of gram positive
bacteria e.g. Acetobacter, Lactobacillus, Pediococcus
• Some inhibitory effect against fungi (but fortunately not
yeast!!)
• Recent work has shown that a minimum of 10 BU’s
needed for any effect (previously though to be 18)?
• Unhopped or very lowly hopped worts can be vulnerable

15. Hop Resins – Biological Stability
Recognition of the inhibitory effect of the NATURAL hop
resins in many non-brewing applications:
•Incorporation into a burn ointment
•Use in deodorants
•Use in mouthwash and toothpaste
•Suppression of Listeria sp. in soft cheeses & other
processed food products (hot dogs in the USA!)
•Bacterial suppression in sugar beet processing
•Control of micro-organisms in distilleries

16. Why Use Hops – Essential Oils?
Precipitation
Bitterness
of proteins
Biological
Aroma
Stability
Foam Anti-Oxidant

17. Essential Oils – Hop Aroma & Character
Wikipedia defines Essential Oils thus:
An essential oil is a concentrated hydrophobic liquid
containing volatile aroma compounds from plants.
Essential oils are also known as volatile oils, ethereal
oils or aetherolea, or simply as the "oil of" the plant
from which they were extracted, such as oil of clove. An
oil is "essential" in the sense that it carries a distinctive
scent, or essence, of the plant.

18. Principal Constituents of Hop Oils
ESSENTIAL OILS
HYDROCARBON OXYGENATED SULPHUR
FRACTION FRACTION FRACTION
50-80% 20-50% <1.0%
• Highly volatile • Volatile • Highly volatile
• Not very soluble • More soluble •Undesirable
•Apparent when •Desirable hop •Sulphury, dirty
dry hopping characters aromas
60+ compounds 230+ compounds 30+ compounds

19. Essential Oils – Hop Aroma &
Character
• Hop oil analysis (in beer) is difficult and complex (GLC,
GLC-MS techniques) – also expensive
• Difficult to be precise in which compounds found in beer
come from hops (9 definitely) as some of the oxygenated
compounds also produced during fermentation
• Linalool is one of the easiest to identify and is used as a
‘hoppy’ marker - > 20 µg/l then beer can be said to be
‘hoppy’
• Difficult to predict aroma effect in beer from rubbing hops

20. The Hop Aroma ‘Contradiction’…
Hop essential oils largely responsible for the
desirable hop aroma in beer
But……….
• No one oil component typically “hoppy”
• Only a few hop oil compounds are found
unchanged in beer (dry hopped beers?)
• Normally hop oil components in beer are below
their taste thresholds
• Additive & synergistic effects

21. Why Use Hops - Polyphenols?
Precipitation
Bitterness?
of proteins
Biological
Aroma
Stability
Foam Anti-Oxidant
Body, Fullness Flavour Stability Health Benefits?

22. Hop Polyphenols – Precipitation of
Proteins (in wort & beer)
Most common causes of Beer Haze:
• Residual starch - malting/mashing regimes
• Oxalate - calcium deficient worts
• β-glucan - poorly modified malts
• Carbohydrate & Protein - damaged yeast
• Lubricants - from can lids
• Dead bacteria - malt
• Protein-Polyphenol complexes

23. Protein-Polyphenol Interaction in Beer
(after Siebert)

24. Hop Polyphenols – Relevance in
Protein removal from Beer?
• “Only 20-30% of Polyphenols in beer are
.
derived from hops” (rest from mash tun
materials)?
• “70% of malt Polyphenols but only 20% of
hop-derived Polyphenols survive precipitation
as hot & cold break during and after kettle
boiling?” (McMurrough et al)
• Hop polyphenols have some importance in
achieving haze stability in beer by removing
large molecular weight proteins

25. Hop Polyphenols – Anti-oxidants
• What are anti-oxidants?
Compounds capable of:
o Delaying, retarding or preventing oxidation
o Reducing the undesirable effects of oxidation
• Hop Polyphenols demonstrate good anti-oxidant activity
and can therefore be shown to be beneficial in preventing
oxidation processes in beer thereby improving flavour
stability
• Flavour stability of hop pellet brewed beers (containing
hop polyphenols) has been shown to be better than CO2
Extract brewed beers (no polyphenols)

26. Hop Polyphenols – Anti-oxidants
• What are anti-oxidants?
Compounds capable of:
o Delaying, retarding or preventing oxidation
o Reducing the undesirable effects of oxidation
Possible health benefits? Help to combat dangerous
free radicals in body thereby:
educing cardiovascular problems
•Fighting the development of cancer
•Reducing the incidence of osteoporosis
•Slowing up the ageing process (arthritis, strokes,
cataracts, alzheimers etc.)

27. Hop Polyphenols - Flavour
Contribution to Flavour:
•Some polyphenols do add a bitter flavour (sometimes
described as astringency)
•Has been shown in taste tests that hop polyphenols add
‘body’, ‘fullness’ and ‘mouthfeel’ to beer
•Compare beers brewed to same bitterness specification
but using:
• Low alpha aroma hop (more weight therefore pro-rata
more polyphenols added)
• High alpha hop (less weight therefore pro-rata less
polyphenols added)
•Low alpha aroma hop beers preferred by tasters

28. Hops & Hop Products
Influences of hops on beer quality
Introduction to the full range of hop products
Different ways of hopping & flavour differentiation
The cost of hops in beer
Questions

29. The Development of Hop Products
First commercial, aqueous hop extracts produced in Germany in the
1800’s 1850’s followed by petroleum ether (USA, 1870’s) and alcohol
extracts (1890’s).
1910 - 1930 First hop oil emulsions produced.
First aqueous iso-extracts produced in the UK; hop powders and
1960’s
pellets introduced into Europe.
Widespread use of Type 90 and Type 45 pellets; stabilised pellet
1970’s
patent and early patents on reduced products registered (USA).
Liquid and supercritical CO2 extraction processes developed;
1980’s increasing use of iso-extracts; iso-pellets patented and fractionated
hop essences available.
Further reduced product patents registered and the more general use
1990’s
of reduced products for foam enhancement and light stable beers.
Publication of patents for non-brewing uses of hops & hop
2000’s
components including many potential pharmaceutical uses

30. The General Benefits of Hop
Products over Leaf (or cone) Hops
• Increased shelf-life/stability
• Increased bulk density/volume reduction
• Improved efficiency of bittering (utilisation)
• Reduction in chemical residues/heavy metals
• Reduced wort (extract) losses
• Opportunity for automated dosing systems
(labour saving)
• Homogeneity
• Provide additional quality benefits (see later)

31. Raw
Hop Products Hops
Concentrated Steam
Pellets Stabilized Ethanol
Pellets Distilled
Type 90 Pellets Extract
(Type 45) Hop Oils
CO2 Hop Isomerized
Extract Pellets Xantho- Hop Oil
Type 45 or 90 Extract Type Dry
Isomerized
Kettle Pure Hop Oil
Extract (IKE) Spent Type Noble
Tannin Xanthohumol
Hops
Potassium Extract
Light Stable
Isomerized
Kettle Extract
Kettle Extract
(LSKE)
(PIKE)
Rho
Beta Concentrate
Iso
Aroma
Concentrate Tetra
Extract
Concentrate
Rho Rho
Light Stable Iso-Extract 35% 10%
Beta 20% 30%
Beta Aroma Tetra
in PG
Extract 10%

32. Objectives of the ‘Newer’ Hop
Products…
To add value for the brewer by:
• Providing greater efficiency leading to
reduced costs – ‘pre-isomerisation’ of
alpha-acids to iso-alpha-acids
• Providing additional quality benefits
compared to ‘traditional’ hop products
o Improved foam performance
o Light stable

33. Hop Products – Kettle Added
(Usually solid materials or resin extracts)
‘Traditional’:
- Leaf Hops - bitterness & aroma
- Hop Pellets - bitterness & aroma
- Hop Extracts - bitterness & aroma
‘New’:
- Pre-isomerised Pellets – b’ness, aroma & cost saving
- Pre-isomerised Extracts – b’ness, aroma & cost saving
- Aroma Extracts – aroma only
- Light stable Extracts – b’ness, aroma & Light stability

34. Hop Products – What is meant by
‘Pre-isomerisation’
• Isomerisation normally takes place during boiling in the
kettle – inefficient (final efficiency in beer 30-40%)
• In pre-isomerised products the alpha-acids are
isomerised to iso-alpha in the product before the boiling
process
• Involves optimising the conditions for isomerisation during
the hop product production process using:
o heat
o magnesium salts (naturally present in wort)
• Usually achieve 50-60+% efficiency in beer

35. Hop Products – Post Fermentation
Addition (usually aqueous liquids)
‘Old’ Technology:
- Dry hops – aroma only
- Isomerised Extract (PFB) – bitterness only
‘New’ Technology:
- Reduced Isomerised Extracts
o Rho (Di-hydro-iso-alpha-acid) – b’ness, Light Stability
o Tetra (Tetra-hydro-iso-alpha-acid) – b’ness, LS & foam
o Hexa (Hexa-hydro-alpha-acid) – b’ness, LS & foam
- Hop Oil Products – aroma only

36. Hop Products – What is meant by
‘Reduced’
• Hop products in which the alpha-acid is firstly converted to
iso-alpha-acids and then modified by the process of
hydrogenation to a ‘reduced’ form
• Because the iso-alpha is in a reduced form it is resistant
to effects of UV light (i.e. doesn’t split and produce
‘skunky’ flavours) therefore referred to as light stable;
can therefore use clear glass bottles
• Some of the reduced products are also more foam
positive than unreduced iso-alpha-acids. The modified
molecular structure encourages even more combination
with polypeptides leading to more stable foam.

37. Hops & Hop Products
Influences of hops on beer quality
Introduction to the full range of hop products
Different ways of hopping & flavour differentiation
The cost of hops in beer
Questions

38. Product Differentiation is a key objective of many
large, regional and craft brewers for new, seasonal
or one-off products.
Arguably most typically (and most easily)
achieved by use of hops by:
• Choice of variety (Paul will hopefully discuss)
• Choice of hop product
• Time and point of addition

39. Product Differentiation.............
Typically achieved by:
• Choice of hop product
• whole hop products i.e. those products
containing the full range of important hop
components – leaf, (iso-) pellets
• partially fractionated products i.e. those
products with some components removed –
CO2 Extract, iso-resin extracts, beta aroma
extracts
• fractionated products i.e. single component
products – hop oil fractions, iso-alpha extract
(including reduced iso-extracts)

40. Product Differentiation.............
Typically achieved by:
• Time and point of addition
o Kettle addition – early or late in the boil [leaf,
pellets, extracts & aroma extracts]
o Addition into hopback, whirlpool or even fermenter
[leaf, (iso-)pellets, (iso-resin-) extracts, aroma
extracts & oil fractions]
o Addition into RBT, in-line pre-filter or BBT [pellets,
(reduced-) iso-extracts, oil fractions]
o Addition into container [leaf hops, oil fractions]

41. Changes in Linalool (μg/l) during Brewing
Hop additions
Fermentation
1 2
(Pellets) & Maturation
60.0
Linalool micro-grams/litre
Whirlpool Beer
50.0
40.0
30.0
20.0
Wort Boiling
10.0
0.0
1 2 3 4 5 6 7 8 9 10 11 12 13
Sample No.

42. Hops & Hop Products
Influences of hops on beer quality
Introduction to the full range of hop products
Different ways of hopping & flavour differentiation
The cost of hops in beer
Questions

43. Cost of a Typical Cask Beer - % Split
(Beer – 4% abv; BU – c.25; brewery: 300,000 – 400,000 barrels pa)

44. Cost of a Typical Cask Beer - % Split
(Beer – 4% abv; BU – c.25; brewery: 300,000 – 400,000 barrels pa)

45. The case for Hops & Hop Products
So for around £0.005 - £0.01 per pint the brewer
can cost effectively achieve........
• Flavour & aroma
• Improved haze & flavour stability
• Light stability
• Improved foam performance
• Microbiological protection
• Cost savings
............... a genuine ‘value-for-money’, flexible
and convenient raw material!!?

46. I rest my case!
Thank you for your attention