For hundreds of years
hops have been used as the 'seasoning' in beer.
Originally a wild-growing weed, the hop, a member of the
cannabis family, is now intensively cultivated. Its
inherent poor resistance to disease and its low tolerance
of adverse weather conditions have led to the development
of many new varieties bred to combat disease whilst
retaining flavour and bittering power.
are used for three separate purposes, besides their
natural preserving properties. Firstly they impart
bitterness. Secondly they combine with the malt to give
the beer its flavour. Their third contribution is the
wonderful bouquet associated with the finest Real Ales
obtain the maximum bitterness from hops, they must be
boiled in the wort for a minimum of one hour. The alpha
acids, which provide the bitterness are insoluble until
they have been isomerised by the long boil. Unfortunately
all of the aroma and much of the flavour is driven off
with the steam. It is common practice, therefore, to add
hops to the boil in stages.
the beginning of the boil the bittering or 'copper' hops
are added. Although much of the flavour disappears during
boiling, each hop variety has its own characteristic
bitterness. In general high alpha hops give a somewhat
harsh bitterness, which could be unpleasant in a heavily
hopped beer. These should be used in mildly hopped beers
or in Stouts where the main flavour is derived from
roasted grains. When brewing beers with a high hop
profile, such as Bitters, Pilsners, Altbiers etc., only
the finest aroma hops should be employed. Late in the
boiling process, about 5 to 10 minutes from the end the
flavour hops are added. These should always be aroma
varieties. There are several methods used to create
bouquet. Certainly only the freshest aroma hops should be
used and these can be stirred into the wort when boiling
is over and left to steep for a while. Alternatively the
beer can be 'dry hopped' after fermentation. This is
conducted either in a conditioning tank (secondary fermenter) or in a keg or cask.
click for larger image
Hops are generally
divided into three categories:
varieties are usually low in alpha acids but high in
essential oils. Brewers wishing to create high class,
heavily hopped beers should use aroma hops for all
three purposes. The bitterness imparted by aroma hops
such as Goldings or Tettnang is totally different
from that derived from high alpha varieties such as
Northern Brewer or Herald.
PURPOSE HOPS. Some varieties, although high in
alpha acids, have quite acceptable aroma properties.
These can be used for boiling and late additions but
are usually unsuitable for dry hopping.
Use only where low bitterness levels are required.
Can be used in dark beers employing large amounts of
recipes in home brewing books have been formulated
without regard for the alpha acid content of the
suggested hops and rarely advise late hopping. This type
of recipe will often produce a completely unbalanced beer
with precious little hop flavour and aroma and should be
used for guidance only. A far better way is to brew to
alpha acid values as is practised commercially. The
internationally recognised standard for measuring
bitterness in beer is the European Bittering Unit (EBU).
Most beers fall between EBU 25 and EBU 65. The following
is a guide to typical EBU levels for the more popular
Brown Ale, Sweet Stout, Wheat Beer, Munich
type Lagers -EBU
Pale Ale, Porter - EBU 30-50
Stout, Imperial Stout, Barley Wine
There is a simple
formula for determining the weight of hops in grams
required to brew to a specified EBU value. This formula
assumes a 20% hop utilisation. Some brewers may better
this utilisation so adjustments may be necessary.
REQUIRED x BREW LENGTH IN LITRES
ALPHA ACID OF CHOSEN HOPS x 2
EXAMPLE: You decide to brew 25
litres of Bitter at EBU 45 using East Kent Goldings with
an alpha acid content of 7.6%. The calculation is as
x 25 =1125........Divide by 7.6 x 2........ = 79grams
IMPORTANT. Only the 'copper hops'
should be included in the above calculation as little or
no bitterness will be extracted from late hops.