Whisky Magazine Issue 56
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Kilning might seem to be a standard practice,but it has a large bearing on the whisky-making process. Ian Wisniewski reports
Kilning may seem an entirely practical function, in order to dry the barley once it has germinated. However, maintaining a consistent regime requires considerable skill, and not only to optimise the yield of alcohol. Kilning also develops the character of the malt, while peating adds an additional range of phenolics.
As part of the malting process, kilning follows steeping and germination, which provides the distiller with direct access to the grain's starch content. Steeping sees the barley hydrated in steeps (vessels) to enable germination.
Starch within the endosperm (main interior section) serves as a food source, enabling the grain to produce the energy required to develop roots and an acrospire (shoot).
As the starch is initially enclosed within proteinlined cell walls, the embryo needs to dismantle these walls to access the starch. Enzymes are also produced during germination, which are vital for the conversion of starch into fermentable sugars during mashing.
Once the starch has been ‘liberated,' further growth is arrested by kilning (applying heat).
Otherwise if the grain were to use starch to continue growing, less starch would be available for the distiller, meaning a reduced yield of alcohol.
The moisture level of the grain is typically around 45 per cent at the beginning of kilning, with an initial temperature limited to around 50 degrees Centigrade. Temperature is a crucial consideration when drying the grain, to render the enzymes temporarily inactive e...