The real magic happens in the WASHBACK - a fermentation vessel that allows the yeast strains
to convert the wort into a fermented liquid called WASH (7-10% alcohol). This takes 2 to 4 days.
Now some two weeks have passed since the malting process began - and so far it hasn't been
that different from the production of beer . In fact, beer could very well be considered the oddly
popular forefather of whisky. One would think that after they discovered that you could turn beer
into whisky there wouldn't be much demand for that kid stuff anymore, but it seems there still is.
But then again I'm not a beer drinker - and the novelty value of drinking the warm wash directly
from the washback wears off fairly soon - especially on a hot summer day. Then I DO prefer beer...
After the malt has been dried it goes into the MALT MILL - a device which grinds the dried malt
into GRIST before the next phase of the process begins. During the MASHING stage hot water
is added to the 'grist' in a large vessel called a MASH TUN , where the starch in the barley is
converted further into the fermentable sugars which are needed to produce alcohol later on.
The picture below shows a relatively small mash tun.
It's the one at Blair Athol distillery, made of wood.
(If memory serves, this was made of Oregon Pine.)
Other distilleries use stainless steel washbacks.
and just like almost all things in the whisky world,
opinions vary about what produces better whisky.
During the MALTING process, barley is soaked in water for 2 or 3 days,
then spread out to germinate. During the GERMINATION stage that follows,
(and which lasts around a week) enzymes turn the starch within the barley
into soluble sugars, who will be converted into alcohol later on in the process.
After the 'green malt' has begun to sprout, it is dried in a KILN to stop the
germination process. Drying the sprouting barley can be done in a number
of different ways these days, but in the distant past mostly peat was used.
Just like different grape varieties are used in the wine production, there are a number of different barley varieties used for the distillation of single malt whisky. The Golden Promise variety
has been popular for many years, but these days Scottish distillers use alternatives like Optic and Chariot
as well. Any variety of barley can be used to produce malt whisky, but if any other type of grain is used (maize, buckwheat, rye, corn, etc.) the result can't be called malt whisky. Well, at least not according to the people of the SWA.
But how do they turn barley into whisky? First, they add water...
The basis of every single malt Scotch whisky is plain old BARLEY.
Well, it used to be 'plain old barley' the distilleries either grew on
their own fields or purchased from nearby farmhouses. These days
production is much more rationalised and barley is often purchased
in bulk and sometimes even shipped in from overseas (France, etc.).
A closer look at unsprouted barley.
The husk of barley
Many Islay malts derive a distinctly peaty character
from the reek (= peat smoke) from the peat fumes.
The liquid that's drained off as a result of this process is called
the WORT - which will later grow up to become Scotch malt
whisky. During the FERMENTATION the sugars in the wort are
converted into alcohol by the addition of special yeast strains.
Different kinds of yeast (brewers yeast and distillers yeast) are
used in different combinations to try and influence the 'yield'
and quality of the final product. In fact, some of the crustier old
malt maniacs are complaining that most of the focus is on yield...
The ancient Egyptians
Anyway - I'll get into more details about the significant chemical traits of copper (and their specific effect on whisky)
in the Advanced Beginner's Guide - I'll get back to the topic of distillation now. The first distillation run produces the
so-called LOW WINES with an alcohol percentage somewhere between 10 and 20%. These low wines do not smell
very nice yet, and they are still full of impurities. So, further refinement is needed. The second distillation run occurs
in a special, smaller still called the SPIRIT STILL. Most Scotch malt whisky is distilled twice, but some distilleries have
also used triple distillation to produce their whisky. Bruichladdich even made a quadruple distilled whisky once...
Some pot stills also have so-called purifiers at the top, for example the spirit still that is used at Ardbeg distillery.
Using a purifier is said to produce a better quality of spirit (mostly by the distillers that use a purifier on their stills ;-)
All Scotch malt whisky is distilled in POT STILLS.
Two different types are used at different stages of
the whisky production. During the distillation stage,
the wash is boiled in a copper WASH STILL and
distilled (and sometimes even more than once).
Alcohol boils more rapidly than water, so the
vapours from the boiling wash can be collected at
the top of the 'swan's neck' of the pot still as they
cool down again and condense back to alcohol.
Now it's time for the DISTILLATION of the wash, in order to increase the ABV.
If you paid attention when you read the chapter about vocabulary you'll know that
'ABV' means the alcohol percentage of the distilled beverage, measured by volume.
Beer was known to the ancient Egyptians and wine was popular with the Romans,
but those are the products of natural fermentation - the kind we see in nature.
It's difficult to achieve an alcohol percentage of over 15% by natural fermentation.
The technique of distillation had to be invented before the whisky could be conceived.
Scotland and Ireland may still be fighting over who invented whisky, but the whisky books I've read say that the first experiments with distillation were done by Arabic scholars as early as the 1st millennium. Given their significant role of these first distillers (and that of Irish monks) in the invention and refinement of whisk(e)y, it's interesting to see how the production and consumption of alcohol is frowned upon in many churches these days ;-)
A very important feature of the pot stills is that they are made of copper. Thanks
to some unique properties of copper the metal is absolutely indispensable for
the distillation of whisky. Experiments with other metals were quite unsuccessful.
The first (HEADS) and the last fraction (TAILS) are sub-standard
material, to be re-distilled together with the next batch of low wines.
The heart of the run is a clear liquid of up to 70% alcohol/volume.
Please note that this liquid isn't 'whisky' quite yet - first it has to
mature for at least three years - at least that's the law in Scotland.
During my quest for the perfect single malt I've encountered foreign
'whiskies' of less than 40% (a fairly loathsome High Land Park from
Thailand springs to mind), but those were exceptions to the rule.
It is said that the shape & size of the pot stills have a large influence
on the malt whisky produced in them. The picture at the right shows
the stills and SPIRIT RECEIVER at the Glenfarclas distillery. The spirit
receiver... erm... receives the spirit from the stills. It was also used by
the excise men (tax collectors) to keep track of production volumes.
Distillation of malt whisky in pot stills is a batch process - unlike the
continuous production of grain whisky. (I'll get back to that a little later.)
Within every distillation run, the distillate is divided into three CUTS of
which only the second cut, the HEART OF THE RUN, will be used;
During the 20th century, the whisky industry and trade used to emphasise the size and
shape of the stills as a major factor in shaping the 'character' of the whisky. However, in
recent years more and more attention has been given to casks. Rightly so, if you ask me...
Shown above: the pot stills at Glenfarclas distillery.
The spirit used to be 'casked' at that strength as well, but these days the fresh
spirit is often submitted to casks at around 63%. The casks are then stored in
special WAREHOUSES where they will have the opportunity to mature next to
their siblings for at least three long years before they are released from captivity.
But hold on, once again we're getting way ahead of ourselves...
Maturation is the topic of the next chapter of this guide. However, before you click
onwards to greener pastures I should probably mention that the distillation of the
grain whisky I mentioned earlier in chapter two is a completely different story.
These whiskies are produced much faster (and in far larger quantities) than malt
whisky in a way that is fundamentally different. Instead of the traditional pot stills,
'Coffey stills' (a.k.a. column or patent stills) are used. I will go into the 'technical'
differences between these types of stills in the Advanced Beginner's Guide.
Grain whisky is distilled in another
These continuous stills were invented in the 1820's and were widely used only a few decades
later because these so-called 'Coffey stills' turned out to be much more efficient than pot stills.
Unfortunately, the more efficient production process eliminates some of the 'flaws' in pot still
distillation that give single malt whisky most of its character. And since most blended whiskies
contain mostly grain whisky they really need to mix in some old-fashioned malt whisky into the
blend to give it personality. When a grain whisky is bottled all by itself (with major brands like
'Blackbarrel' and 'Invergordon') I usually don't care too much for the contents of the bottle.
The relatively young 'Greenore' (eight years old) from Ireland is a notable exception.
Only a minute percentage of the grain whisky that is distilled is bottled as a single
grain whisky (vatted grain whiskies are rare). The vast majority of the grain whisky
is used for blended whiskies - and the vast majority of those don't need old grain
whisky for that blend. As soon as it has passed the legally required minimum age
of three years most grain whisky is used in a blend. The focus for these 'volume'
whiskies is often a low price, so the casks that are used for these grain whiskies
are usually not the very best of casks. There are, however, plenty of exceptions
to this rule. Sometimes an exceptional cask can push a grain whisky of just ten
or twelve years old to heights beyond the levels of a malt whisky of similar age.
But as I said, those are exceptional exceptions...
Which conveniently brings us back to the topic of the next chapter: Maturation...
Handbook of Whisky (Dave Broom)