Peaty Whisky: An Overview
As the product of the fermentation and distillation of barley, whisky is the result of hundreds of years of history. Begun in the ancient civilization of Babylon, the process of distillation was first used in the production of perfumes. After centuries of refinement, both distillation and fermentation were brought to Ireland and Scotland by Christian monks some time between the 11th and 13th centuries. These Christian monks used the process to produce alcoholic beverages which were then incorporated into religious ceremonies. In the following centuries, Scotland had refined the process of distillation to such a degree that they’d become expert in the production of whisky. By 1494, whisky had become widely popular, and it made its first appearance in literature in that same year.
In 1541, King Henry VIII of England dissolved many monasteries in Scotland, leaving a large number of monks unemployed. Soon after, the monks spread the art of whisky distillation throughout the country until 1756 when a poor harvest led the English crown to impose heavy taxes on unlicensed distilleries. This resulted in an era of smuggling and “moonshine” – the illegal production of peaty whisky by night so as to avoid detection. Due to subsequent heavy taxation, whisky became a scarce commodity in many countries and even served as a form of currency during the American Revolution. In more recent history, although alcohol was prohibited in the United States throughout the 1920s and into the early 1930s, the government permitted the sale of whisky sold from licensed pharmacies for medicinal purposes.
Single-malt whisky begins its journey in the form of barley, a grain originally cultivated in Ethiopia, Babylon, and southeast Asia. Traditionally, however, the barley used in the production of whisky has been grown in Scotland. After the barley is harvested, it is steeped in water and then laid out onto malting floors, where it is periodically turned over. Once it is on the malting floor, the barley is left to germinate for a period of a few days. This step is important because it enables the starch in barley to be converted into sugar, a necessary ingredient in fermentation. After about a week or so on the malting floor, the green malt is put into a kiln to dry in low heat. During this drying process, peat may be added to the fire. Smoke from the smoldering peat contains phenols, which are the specific compounds responsible for the smoky flavor in peaty whisky.
Consisting of decomposing plant and animal matter, peat is found in bogs throughout the Islay region of Scotland, parts of northern Europe, and even in New York. This rich organic matter is dried into briquettes and is then used as fuel. Although peat has an effect on the whisky’s flavor at the time of drying in the kiln, not all peat will impart the same flavor. Topsoil, or peat from the uppermost layers, creates more smoke when it burns, but peat from deeper layers will burn longer. Thus, the slow-burning, deeper layers were traditionally preferred over topsoil because it provided the fuel for the distillation process. However, in more modern times, peat is used more for its flavor and can produce both lightly and heavily peated whiskies.
After the malt has been thoroughly dried, it is ground into grist, resembling coarse flour in texture, and is mixed with progressively hotter water. The result of this mixture is wort, a sugary liquid which is then fermented. Yeast is added to the wort and is left to ferment for two days. During this fermentation process, the yeast feeds on the sugars and produces alcohol. The resulting wash is then ready for distillation.
The first stage of distillation serves to separate the yeast, water, and pot ale from the alcohol. Pot stills are heated to slightly below boiling, and the vapor containing the alcohol passes up through the neck and into the worm. From there, the vapor is condensed back into liquid, resulting in the low wines. These low wines are then distilled yet again in a spirit still. Both the foreshots and feints – the more volatile and oily compounds of the low wines – are reincorporated with subsequent low wines. The part that is kept for the maturation process is called the heart of the run. At this point the heart of the run contains about 68% alcohol by volume. After passing through the spirit safe, the resulting spirit is placed into casks to mature.
While whisky is produced in many countries, only whisky which has been produced and matured in Scotland for a period of at least three years can be called Scotch. The whisky derives its color from the wooden cask it matures in, and some of it turns into esters. These compounds, along with the maturation process in general, help give each whisky a unique flavor. While the minimum maturation period is three years, many single-malt whiskies are aged for as long as 15 years.
Both Taiwan and Japan have entered into the whisky marketplace, producing some of the world’s finest whiskies available. The Nikka and Yamazaki distilleries in Japan produce both blended and single-malt whiskies, which are well-loved and favorably received around the world. However, the Kabalan distillery of Taiwan recently won awards for producing the World’s Best Single Malt and World’s Best Single Cask Whiskies from the World Whiskies Awards in 2016.
Peaty whisky derives its flavor from the peat used as fuel for the fire during the drying process. However, not all peat is equal in the flavor it imparts to the finished product. Though there are peat bogs throughout northern Europe, and even some in New York, not all peat can be used in the production of whisky. Both its age and composition can affect the flavor of the whisky. For example, peat containing either heather, moss, or seaweed will yield different flavors to the finished product, and older peat near the bottom of the bog will produce fires which burn more slowly, as opposed to the newer peat near the top which will produce a lot of smoke. Additionally, each distillery may blend up to 50 different single-malt whiskies to create a signature flavor profile. Lastly, single-malt whiskies may be blended with more subtle grain-based whiskies as well.