All about making whisky
Of all the various grains used to make different types of whisky, barley is the grain that contributes the most to a whisky’s aromatic range. For over three hundred years now, distillers have been paying particularly close attention to the barley they select, which represents a distillery’s greatest expense. A true source of life, barley lies at the heart of the production process of uisge beatha.
In 1678, a certain Sir Robert Moray wrote an article that claimed that malt could only be produced from a single grain: barley. In those days, a number of different varieties were already known. The most renowned was an ear of barley comprised of two rows of grains. The other, more commonly used, featured six rows of grains. This second variety was known as bere, an ancestral form of modern-day barley that is still grown in the Orkney Islands to make bere bannock, a flat bread that long served as the islanders’ staple food. Distillers have always prioritised local barley farmers. However, from the end of the 19th century, distilleries were obliged to start importing. Driven by the general surge in the popularity of whisky, they regularly received shipments of whole barley from France, Denmark, Russia and the Baltic states in particular. One of the places most affected by this ‘barley rush’ was the port of Campbeltown on the Kintyre peninsula, which in 1873 was receiving several cargoes of barley week to be sent on to the thirty-odd distilleries that were in operation at that time.
In the 1950s, new varieties of barley continued to appear, with new quality categories regularly replacing older ones, such as Spratt, Plumage, Archer, Proctor, and Marris Otter. Most came from northern England, southern Scotland or Canada. At the end of the 1960s, technological advances in barley harvesting and storing led to a new Scottish variety appearing on the market, named Golden Promise. Despite its vulnerability to mildew attacks (mould), Golden Promise was the favoured barley among distillers for almost twenty years, and accounted for up to 95% of the barley grown in Scotland. Its decline began in 1985. Despite the existence of new varieties, some distillers remain fiercely attached to Golden Promise, especially Macallan. But most turned to other types, particularly Optic, which were more resistant and had a higher alcohol yield.
Faced with a vast array of available varieties, a selection process is necessary. Not all characteristics are beneficial to producing alcohol. Barley that is rich in protein, for example, will be used as cattle fodder or in making grain whisky. For producing malt whisky or Scottish ales, distillers and brewers opt for barley that is rich in starch which produces fermentable sugars and consequently alcohol. Distillers check the barley’s quality on delivery. In particular, they check that the grain shows no signs of rot, which combined with careless harvesting, steeping and germinating techniques, results in undesirable aromas.
Since the 1970s, malting (the first step in converting grain into alcohol) has not been carried out within the distilleries themselves. Only five distilleries, of which Balvenie is one, still malt up to 30% of their own barley.
This process is lengthy and expensive, and is now sub-contracted out to mechanised malt houses. Industrial malting has a number of advantages compared to traditional malting. Over and above issues of time and cost, the malt houses produce a consistently high standard of malted barley in line with each distilleries individual specifications. Often perceived as a single-step process, malting actually involves three stages:
Once harvested, the barley enters a natural dormancy period. Comprised of a husk containing an embryo (the future plant) and a pouch of starch (reserve of energy), the barley is subjected to several humidifying and oxygenating stages in order to activate the dormant embryo. The time required for this operation varies from forty-eight to seventy-two hours depending on climatic conditions, and ends when the grain’s moisture content increases from 15% to over 40%. Germination can then begin.
The moist barley is then spread across the malting floor in thick layers of between 30 and 50 cm. As the embryo develops, the solid walls protecting the starch disintegrate. The starch transforms into a kind of whitish, soft flour, whose sugar content will be extracted during brewing. The heat generated by the growing embryos means the barley needs to be frequently turned. This is traditionally carried out using wooden shovels (shiels) or rakes. This physically challenging process must be repeated an average of three times per day to prevent the rootlets becoming entangled. When the rootlets have grown two or three millimetres long, germination is interrupted to avoid the embryo feeding off the grain’s sugars. At this stage, the barley is known as ‘green malt’. It is transferred to the oven (kiln) to be dried.
Drying, or kilning, used to be exclusively carried out using peat, charcoal or coke. These days, malt houses are equipped with both ovens for the peat fire and burners that generate hot air. Once dried, the malt is stripped of its impurities, rootlets and other residue before being delivered to the distilleries.
Often seen as a straightforward intermediary step in the alcohol production process, malting is rarely acknowledged for its contribution to a whisky’s aromatic palette. Yet the fuel used during drying significantly affects the malt’s aromatic profile. When dried with hot air, the malt takes on toasted and biscuity notes. When dried in a peat fire, it develops roasted, smoky and medicinal notes that linger after distillation. After the malting process, the malt is stored and ground into a rough flour, called grist, using a malt mill. The ground mixture is comprised of 70% grist, 20% husk residue and 10% flour. These proportions must be strictly applied in order to avoid hindering the brewing process. At this stage, water can be used to extract the sugars that would previously have been inaccessible.