Agriculture Reference
In-Depth Information
hop products/extracts (see Table 16.2) and by the dry hopping (a common term
used to describe the addition of several hop cones to the cask after fi lling to supply
fresh hop aroma but no extra bitterness) of cask-conditioned beers.
Following harvesting, hops are dried and compressed often in sacks and bales
for large quantities, or double silver foil vacuum packs for smaller requirements.
Breweries generally purchase pack sizes as close to the brew length usage as
possible and purchase the latest harvest hops, which are stored religiously in a
Table 16.2
Hop products and point of use
Brew kettle
Post fermentation
Non-isomerised:
Whole hops
Hop pellets
1
Stabilised hop pellets
2
Isomerised hop extracts: iso-α-acids
7
Liquid and supercritical CO
2
extracts
3
Reduced isomerised hop extracts:
Ethanol extract
4
Dihydro-(Rho)-iso-α-acids
8
Isomerised hop products:
Tetrahydroiso-α-acids
9
Isomerised hop pellets
5
Hexahydroiso-α-acids
10
Isomerised kettle whole hop extract
6
Pure hop oil/oil rich (CO
2
) extracts/
emulsions
11
Isomerised hop extracts: iso-α-acids
7
Soluble hop aromas
12
Reduced isomerised hop extracts:
Dihydro-(ρ)-iso-α-acids
8
Notes:
1
Whole hop cones are ground then blended and compressed into pellets (commercially known as
Type 90 and Type 45 pellets) providing bitterness and hop aroma
2
Conversion of
α
-acids into more stable salts by mixing 1-2% MgO or CaO during processing
3
Hop pellets are extracted using CO
2
under liquid or supercritical conditions. Contains
α
-acids,
β
-acids and essential oils for part or complete replacement for whole hops or pellets
4
Extraction of aroma or bittering hops with fermentation alcohol (ethanol). Contains complete range
of hop bitter acids and hop oil for part or complete replacement of whole hops or pellets
5
As stabilised hop pellets but stored at elevated temperature for a controlled period resulting in
conversion of the
α
-acids to bitter iso-
α
-acids with high effi ciency. Results in signifi cantly improved
bittering utilisation of the bittering acids and excellent storage characteristics
6
Contains isomerised
α
-acids,
β
-acids and essential oils produced from CO
2
extract and can be used
as a complete replacement to fi rst hop or late hop addition to the kettle
7
Produced from CO
2
extract and contains only purifi ed iso-
α
-acids. Can be used to top up bitterness
or used as partial hop replacer
8
Purifi ed, reduced iso-
α
-acids that can be used in the kettle or post fermentation for light stable beers
(protection against light-struck fl avours such as 3-methylbut-2-ene-1-thiol or 'skunk thiol'). Provides
a smooth, soft bitterness
9
Derived from
α
-acids and
β
-acids and used to enhance beer foaming and lacing ('cling'). Offers
complete light stable beers (in the absence of normal
α
-acids and iso-
α
-acids). Often used with
rho-iso-
α
-acids. Provides a sharp bitterness and astringent at high levels
10
Derived from
α
-acids. Offers light stable bitterness with foam enhancement with a complex
progressive bitterness
11
Produced from whole leaf hops and contains the complete range of essential oils at high
concentration. Used as an emulsion for dry hopping (not light stable)
12
Derived from fractionation of CO
2
hop extract. Available as single hop varieties or as generic
aroma types (such as fl oral, citrusy, spicy, fruity) and can be added to bright beer without introducing
haze or affecting foam stability (light stable). Reduces hop fl avour variability
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