|Hops, Hops, Hops
So you like a "hoppy" beer. Join the club. Hopped up IPAs are now the single
most popular craft beer style in the USA so it makes sense to take a closer
look at the flower that gives the power to beer.
Hops are the female flower clusters (commonly called seed cones or
strobiles), of a hop species, Humulus lupulus. As the ancients said, hops
grew "wild among willows, like a wolf among sheep," hence the Latin name
Hops are perennial plants that flower for many seasons. This climbing vine
with dark green, heart-shaped leaves, can reach up to 15 to 25 feet in height
by the end of the growing cycle. There are over one hundred different varieties
of hop flowers that can be used in the brewing process, which results in
hundreds of different flavors!
Hops appear to have been used in the breweries of the Netherlands in the
beginning of the fourteenth century. In England they were not used in the
composition of beer till nearly two centuries afterwards.
Hops are used primarily as a flavoring and stability agent. Prior to hops, the
stronger (more alcoholic) the beer was, the longer it kept. The addition of
hops served as a natural preservative, thus allowing beer to be weaker and
still keep longer.
One of the most important effects of hops in the brewing process is to add
bitterness to the beer. This bitterness balances the sweetness that comes
from the other major ingredient in beer - barley malt. Without the bittering
effect of hops, beer would be a very sweet drink.
Hop bitterness comes from a group of compounds called alpha acids. The
major alpha acids are humulone, cohumulone, and adhumulone. These alpha
acids must be added to the wort and boiled for 45 - 60 minutes. The acids will
enter the wort fairly quickly, but if they are not chemically altered by a process
called “isomerization”, they will not remain in the wort when it is cooled.
Hops also contain essential oils that provide flavor and aroma characteristics
to beer. The most important of these oils are myrcene, humulene,
caryophyllene, and farnesene. Unfortunately, they are very volatile. Thus, if you
want to achieve the flavoring and aroma characteristics instead of bitterness
you only boil them for a short time. The standard process is to use a 15 minute
boil to get flavor components and a 5 minute (or less) for aroma
Another method for achieving hop aroma in beer is called “dry-hopping”. This
refers to putting hops into the fermenter. Since the beer will not be boiled, the
essential oils will not be dissipated.
Hops come to the brewer in three major physical forms:
Whole (or cone) hops - Essentially, this is the just the dried hop cones as they
come off the plant;
Hop pellets - Hop pellets are produced by grinding the hops into a powder.
This powder is then formed into small pellets. The oils and resins in the hop
act as the binder to hold the pellets in the desired shape.
Hop plugs - Hop plugs are just compressed whole hop cones.
In choosing which form is best, there are several factors to take into account.
Most important is the freshness of the hops. Hops should be keep cold and
away from air.
Whole hops are particularly susceptible to losing their freshness since they
have so much surface area exposed to air. This is one of the major
advantages of pellets - by being so compact, the amount of surface exposed
to air is much smaller than with whole hops. On the other hand, the grinding of
the whole hops to create the pellets results in the loss of some oils. Thus,
whole hops may possess more of their original character then hop pellets do.
Hop plugs are considered to be a compromise between the whole hops and
From a practical brewing standpoint, there are other issues. More varieties
are available in pellet form. This is probably due to the economies in shipping
and storage that result from the reduced size.
Techniques for removing hops from wort will also vary depending on which
form is used. Whole hops or hop plugs may be removed with a screen filter
system. Hop pellets, on the other hand, reduce to a very fine powder sludge
which will clog most screens. Therefore other methods must be used to
separate hop pellets residue from wort .
Aside from it's preeminence in brewing hops have a long and proven history
of herbal use, where they are employed mainly for their soothing, sedative,
tonic and calming effect on the body and the mind. Their strongly bitter flavor
largely accounts for their ability to strengthen and stimulate the digestion,
increasing gastric and other secretions.
So here's to hops..... what would we do without you?