Continued from part one
Whisky has been one of the most popular spirits for many centuries – not least because of the relatively few ingredients needed to make it. The production of whisky requires grain, water and yeast.
Whisky is distilled from barley, corn, rye or wheat: Barley is the most suitable – the starch contained in barley is particularly easy to convert into fermented sugar.
When whiskey production first took hold in the U.S., whisky producers faced a problem: Barley grows much more poorly in the U.S. than in whiskey’s homeland in the British Isles. Corn, however, grows splendidly in the U.S.: This gave rise to a new type of whisky, christened bourbon (also called Tennessee whisky), which must be made from at least 51% corn.
Rye is also used in the production of North American whisky from the USA and Canada. Wheat is used to produce grain whiskeys, which are often used as a component of a whisky blend.
Water plays a central role in the production of whisky: not only does the quality of the water matter, but also the degree of hardness of the water. The whisky develops its taste depending on which substrate and which rock the water used passes through. For example, a whisky made with water from the Scottish Highlands tastes different from a whisky from another region.
Yeast is needed to convert the sugar extracted from the grain starch into alcohol. Although barley malt contains wild yeasts, these are not sufficient to trigger fermentation.
Therefore, whisky producers resort to cultured yeasts, which also influence the taste of the whisky.
Many distilleries grow their own yeast cultures: The yeast cultures are classified as a trade secret at numerous whisky distilleries. Whisky is made from relatively few ingredients, but the quality of those ingredients matters more than in almost any other distillate.
Regardless of what grains are used to make it, the method of making whisky is always the same.
The first step in the production of whisky is malting: This is where the barley begins to germinate. During this process, the starch contained in the barley grain is converted into maltose. The process is triggered by moistening the barley. Heat is generated during this process. To ensure that the heat is evenly distributed, the grain must be constantly circulated.
The malting process must be stopped exactly when the grain has a perfect maltose content. Stopping the process at exactly the right moment requires a great deal of experience on the part of the maltster. The maltose content later determines the alcohol content of the whisky.
Since malting is a process that takes weeks, the process accounts for over half of the cost of producing a whisky: Nowadays, malting is outsourced and distilleries hire specialized companies to produce barley malt.
The next step is to dry the malt: kilns are used to dry the malt over a fire. To produce a classic single malt whisky, a peat fire is lit for drying: This gives the whisky a particularly smoky flavor. When, in the course of industrialization, other fuels such as coal and coke became sufficiently available, producers resorted to these raw materials. Today, peat is usually only used at the beginning of the kilning process, after which coal and briquettes are used.
Now the malt is freed from the germs and ground into grist in a mill: In the process, the sugar is released from the barley grains. The resulting flour is mixed with hot water in a mash tun: This continues the conversion of starch into maltose. Initially, the water is at 60 degrees Celsius, but later the vat is heated to 80 degrees.
During this process, the hot and sweet wort is drained a few times.
The wort is now cooled to 20-27 degrees and poured into fermenting vats. Yeast is now added to these fermenting vats, which converts the sugar into alcohol. During this process, the wort becomes wash: wash refers to a clear liquid made of water, yeast and 5% alcohol.
Nowadays, this process of fermentation is completely mechanized: In the past, this process had to be strictly supervised.
Now comes the last step before bottling in the whiskey barrels: distillation. Here, the alcohol is extracted from the wash: This is done with the help of specially shaped boilers, the pot stills. For the following process, it is important to know that alcohol boils at 78 degrees Celsius and water at 100 degrees.
During the distillation process, the mixture in the pot stills is heated and the alcohol rises as vapor and condenses at the top of the vat, which is shaped like a gooseneck.
The liquid produced here is called low wines and is whisky in its raw form with an alcohol content of 21%. The substance is then distilled a second time before it is ready to be put into barrels. Irish whiskey is distilled three times, while Scotch is usually distilled only twice.
Bottling and storage
After the master distiller has checked how pure the alcohol content is, he divides the distillate into three parts: The head, the heart, and the tail. Only the heart is bottled, the other components are redistilled and used in the next distillation process.
At the end of the distillation process, the alcohol content of the distillate is between 65 and 70 percent. With the help of spring water, the whisky is now reduced to an alcohol content of about 63%, which is optimal for long storage.
Now the whisky is ready to be filled into barrels: Traditionally, whisky is bottled and stored in 500-liter oak barrels. In Scotland and Ireland, a whisky is stored in the barrel for at least three years, and in the USA for at least two years. Many whisky connoisseurs believe that the longer the storage time of the whisky, the more aromatic the drink tastes.
Cover picture: © Simon von Ludwig