John I. Haas, Inc

John I. Haas, Inc

Ingredients:
7 feet deep. These are called “pockets”; each holds approximately 75 kg (or
1.5 zentners—the zentner [50 kg] is the traditional unit for quantifying the

Directions:
weight of hops). In the United States, hops are packed into bales measuring
20 by 30 by 57 inches and weighing 200 pounds (91 kg or 1.8 zentners).
The hops must be stored cold and in an airtight condition, to counter the
degradation of the bitter principles and the attendant development of nasty
cheesy characteristics. As I will show, though, the use of hop cones without
some form of modification is increasingly rare these days.
Hop Analysis
As with all raw materials used in the brewing process, specifications are ap-
plied to hops that must be met if a transaction is to be conducted between
the hop merchant and the Brewer. It is fair to say that the analysis of hops
remains somewhat more primitive than that of other brewery ingredients.
Many of the assessment criteria for hop quality depend on noninstrumental
judgment by experts. First the sample of hops will be inspected visually
for signs of deterioration, infestation, or weathering. Then a sample will be
rubbed between the palms of the hands before sniffing the contents: the as-
The Wicked and Pernicious Weed 117
sessor is looking for any smells associated with deterioration and, just as im-
portant, is determining whether the “nose” is consistent with what is ex-
pected from the variety in question. The buyer is not looking for a charac-
ter that will manifest itself in the finished beer, for the aroma of hops and
that of hoppiness in beer seldom bear a simple relationship. Rather she is
looking for certain varietal characteristics in the aroma to confirm that the
hop is what it is purported to be.
The prime quantitative parameter on which hop transactions are made
in the United Kingdom is the lead conductance value. Lead acetate is added
to an extract of hop resins in methanol, and the conductivity of the mixture
is measured. The lead ions react with the resin (cid:7)-acids (which are the pre-
cursors of the bitter compounds). Once all of the lead has complexed and
surplus lead is present, the conductivity starts to change. The more lead ac-
etate needs to be added before the conductivity changes, the more (cid:7)-acid is
present. In the United States (cid:7)-acids are measured spectrophotometrically:
as the extent to which an extract made from the hops absorbs ultraviolet
light in proportion to the amount of resins present.
Types of Hops
There is an increasing tendency to classify hops into two categories: aroma
hops and bittering hops. In reality they are merely variations on a theme. All
hops are capable of providing both bitterness and aroma. Some hops, how-
ever, such as the Czech variety Saaz, have a relatively high ratio of oil to
resin, and the character of the oil component is particularly prized. Such