Making the Malt
Malt Whisky is produced by an ancient process involving only three
ingredients: barley, pure soft Highland water, and yeast.
Barley is steeped in water then allowed to germinate
until roots and shoots start to appear. During germination enzymes are
produced which can convert the starch in the barley to fermentable sugars.
Germination is then stopped by drying the grain, or 'green malt' as it is
known, in the malt kiln over a peat fire whose smoke helps to give the final
product its peaty flavour.
The malt is milled and the ground malt or 'grist' is mashed or
mixed with hot water and fed into a mash tun. The soluble starch is thus
converted into a sugary liquid known as wort which is drawn off from the mash
tun for fermentation.
After cooling the wort is passed into large vessels known
as washbacks where it is fermented by yeast into a weak alcoholic solution.
The wash is distilled twice in large copper pot stills. The first
distillation in the wash still produces a liquid called low wines which is
distilled again in the low wines still to produce spirit. At this stage it
is the skill of the
stillman which contributes to the traditional quality and flavour
of his distillery's malt whisky. Only the middle fraction of the second
distillation is collected.
The newly distilled spirit is filled into
oak casks and transferred to a warehouse where it is left
to mature for a number of years. During maturation the
spirit loses its sharpness, taking on the mellow mature
flavour of the full bodied single malt.
After maturation the whisky is reduced
to the strength required by the addition of soft water.
The whisky is then filtered carefully and filled by
automatic machines into bottles which are then sealed
and labelled. The bottles are then packed in cases for despatch.
© John Butler, University of Edinburgh and contributors