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Build your own distillery
(Part II)
Malting
Whisky begins as barley, water, yeast and peat. A
few distilleries still grow much of their own
barley, or at least procure it from local
farmers. What is important is that the grain be
of good quality, however this is assured. It
takes about 2 kg of barley to produce a litre of
whisky, so a modest distillery will need around
2000 tonnes of malted barley per year.
The barley is malted, meaning it is soaked in
water, spread, and allowed to germinate. When
barley germinates, it produces an enzyme that
converts the starch in the grain into sugar. As
soon as germination has produced this enzyme, but
before growth has used up much of the starch, the
germination process is halted by drying.
There are two methods for producing malted
barley. The first is traditional and, as with all
things labelled "traditional", is
labour intensive. The grain is spread on the
malting floor to germinate. One doesn't quite
know how the grain manages this unaided in the
wild, because here you have to help it along by
regular turning. If you're really traditional,
you use a shovel. In distilleries that still have
their own malting floors, you will find the
shovels off in a corner, covered with dust, while
the grain is turned by a back-saving mechanical
contrivance looking rather like a lawnmower with
teeth. Underneath the malting floor is space to
build peat fires. Once lit, the heat from these
fires dries the grain and stops germination, and
the peat smoke adds some of the most notable
taste and aroma components to malt whisky. All
malt drinkers know (and either love or hate) the
Islay distilleries that believe there cannot be
too much of a good thing.
Most distilleries use the second method of
producing malted barley, namely, let somebody
else do the hard work. There are a number of
central malting houses that produce malted barley
to order. Although the malting takes place away
from the distillery, the process is carefully
controlled and the amount of peat smoke added
during drying can be precisely specified.
After drying, the barley is coursely ground into
grist. This is the true input to whisky-making,
and your 2000 tonnes of barley have produced
about 1600 tonnes of grist.
The grist is mixed with hot water in large metal
vessels called mash tuns. The water serves both
to activate the sugar-producing enzyme and to
dissolve the resulting sugar (along with many
other components). The resulting liquid, wort, is
drawn off to be fermented. The solids remaining
behind, about one-quarter of the original, are
used as cattle feed.
The wort is then fermented, producing wash. This
is done in huge wooden vats, called washbacks,
which are usually made of Oregon pine and hold
anything up to 45000 litres. If you've never seen
a washback, try to envision a two-story hot-tub;
and the fermentation process is indeed hot. As it
ferments, the wash tends to foam, so be generous
with the size of the washback and don't forget to
stir.
The fermentation is caused by a mixture of
cultured and brewers' yeast, which you add by the
bagful to the wort, and by bacteria occurring
naturally in the atmosphere. These bacteria are
of the same sort that ferment cabbage into
sauerkraut, so perhaps you could diversify if the
whisky doesn't work out.
Wash has an alcohol content similar to that of
ale, which is to say a lot lower than what one
expects of a good dram, so the next step is...
Distillation
One of your more important decisions is the
number of stills the whisky-to-be passes through
en route to the cask. Lowland malts are normally
distilled three times, as are traditional Irish
malts. That is, the fermented wash is distilled,
the product of the distillation distilled again,
and the product of this second distillation is
distilled yet a third time. This produces a
characteristically lighter malt, in contrast to
the double distillation used in most Scottish
distilleries. There are exceptions to this, for
example, Springbank distills their whisky
"two-and-a-half" times; a complicated
story best understood over a dram of said whisky.
The individual still also makes a difference.
Although we are speaking here only of malt whisky
made in pot stills, there are nonetheless
variations on the theme. Stills come in various
shapes and sizes, though since 1814 the minimum
has been several hundred gallons. This
restriction was enacted based on the assumption
that it was rather difficult to hie off into the
woods with several tons of copper when the excise
man came around. But one can stay at the legal
minimum, producing numerous very small batches,
or use larger stills and produce fewer but larger
runs of whisky.
This decision is quite important, as the
composition of whisky changes continuously during
the distillation. The early part of the
distillation, called the foreshots, is
undrinkable. This is the stuff that makes you go
blind, and is understandably not wanted in malt
whisky. The latter part of the run, the feints,
contains heavier elements such as fusel oils, and
has a noxious taste. However, fusel oils are
important flavour components in malt whisky, and
it is a matter of judgement when they have
reached too high a concentration. Between
foreshots and feints comes the middle cut, which
will be run into casks for ageing as malt whisky.
Some distilleries take a very narrow cut, to
produce a more consistent whisky, whereas others
value the flavour balance that comes from a wider
cut of the distillation.
Assuming that you want the usual
double-distillation, you will need one or more
wash stills and one or more smaller spirit
stills. The exact size and shape undoubtedly have
profound effects on the whisky they will produce;
unfortunately, you won't find an analysis in your
local library, as no one understands just what
these effects are. Better to visit your favourite
distilleries, take careful measurements, and
drink a few drams just as a matter of quality
control.
Not to be forgotten is the lyne pipe, which
conducts the evaporated liquid away from the
still and into the worm. The size, shape, and
height of the lyne pipe helps determine which
volatiles make it into the final whisky and which
recondense and fall back into the still. So once
you have found a good size and shape, you need
only find an artistic hammer-wielder to add a few
carefully placed dents and pings. After all, who
are we to contest legend?
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