The ideal grist ratio for making Scotch whisky
Nowadays, milling is often the first stage of the Scotch whisky production process that takes place at a distillery. The 4 roll mill is most commonly used and, as explained in this diagram, milling is simply the process of grinding dried malt through giant rollers, creating a coarse flour called grist.
The grist is made up of three fractions: husk (20%), flour (10%) and grits (70%).
An extremely important part of the process, milling can help a distillery in achieving maximum yield of alcohol from the malted barley. While a distiller can tell how good the grist is by sight and touch, a grist analysis will be carried out to determine the percentages of the various fractions in the grist.
The grist ratio is a vital parameter for the distiller as it tells them how well the malted barley has been ground in the mill. Each mashtun requires a certain ratio of husk to grist to flour. The grist analysis will show the distiller if they have what is needed for the efficient use of the mashtun. The appropriate grist ratio allows the distiller to get the best alcohol yield from the malted barley and makes for easier processing.