In the production of Malt Scotch Whisky the basic raw materials are limited and consist of barley, water and yeast.
The process comprises five distinct stages.
MALTING which converts barley to MALT.
MASHING which produces WORT (sugar solution) from ground or crushed MALT.
FERMENTATION that produces WASH (a weak, crude, impure spirit) consequent upon the introduction of YEAST in the WORT.
DISTILLATION that strengthens and purifies the spirit contained in the WASH and also separates the solids contained in the spirituous liquor.
MATURATION that transforms the raw SPIRIT into WHISKY.
In two of the above stages the distiller is concerned with the behaviour of living organisms. In MALTING the involvement is the controlled germination of the barley corn and in FERMENTATION the action of the yeast when placed in a solution rich in fermentable sugars and growth factors. All living organisms are susceptible to conditions of their environment and many of the distiller's problems arise therefrom.