30 August 2019
Scotch Whisky Cereals Technical Note: 4th Edition
By law, Scotch Whisky must be distilled and matured in Scotland using only three raw materials – cereals, water and yeast. The industry is supportive of Scottish agriculture and 87% of barley and 50% of wheat requirements are sourced in Scotland. Seed producers, farmers, grain merchants and maltsters are all critical to the industry’s success.
Scotch Malt Whisky must use 100% malted barley and be distilled in a pot still. Preferred barley varieties are those which produce high alcohol yield, easy and consistent processing, no glycosidic nitrile and high enzymes for grain distilling malts. Barley for pot distilling requires a high starch content (hence lower protein and higher spirit yield). A nitrogen level of about 1.5% in the barley is considered optimum and will be the maltsters’ target, if the crop quality allows. Malt specifications are agreed upon by distillers and maltsters on an individual basis and are subject to change as a result of commercial trading issues, availability and harvest quality.
Grain Scotch Whisky is normally made from unmalted cereals (usually soft winter wheat and maize) with the addition of around 10 % “high DP” malted barley and is typically distilled in a continuous column (patent) still. “High DP” barley will normally exceed 1.80 % nitrogen to achieve the required level of enzyme activity for conversion of the whole mash to fermentable sugars. Grain whisky is most commonly used as a component part of blended Scotch Whisky, which accounts for around 90% of all Scotch Whisky sales.
Sustainability has increasingly become a major consideration for distillers for both grain and malt distilling. The Scotch Whisky industry, supported by the SWA, has adopted a comprehensive Environmental Strategy with a view to reducing progressively the impact Scotch Whisky companies and their supply chain have on the environment.
The Scotch Whisky industry invests significantly in cereals development via direct research projects, mainly through the Scotch Whisky Research Institute. Projects relevant to distilling have included research on malt processibility, barley skinning, malting enzyme development, climate change, barley disease resistance and effects of barley variety and environment on spirit character. The International Barley Hub is a major £38 investment in barley science by UK and Scottish governments under the Tay Cities Deal. This will involve a state of the art laboratory building to be site at the James Hutton Institute near Dundee, which is already a centre of plant science excellence. There are well-established systems for the breeding and selection of modern malting barley varieties with input from the entire supply chain. When a new variety is put into the market it will have been assessed on its agronomic merit and end user potential and rated on the AHDB, SRUC and Malting Barley Committee approved lists. However, it is ultimately a commercial decision of individual Scotch Whisky companies as to which varieties or technical specifications they wish to apply when procuring cereals to produce their spirit.
The purpose of the Scotch Whisky Cereals Technical Note is to help achieve a common understanding of the importance and use of cereals within the industry. A copy of the 4th edition of the document (August 2019) may be viewed and downloaded here.