The fascinating process of whisky making

Whisky—spelled "whiskey" in Ireland and the U.S. is a famous distilled spirit. As a very popular alcoholic beverage, it manages to find its way into many nations' cultures. It is made from grain mash, fermented, distilled, and matured in oak barrels which vary across brands. Like all other types of spirits, the base product varies and tends to be linked with the location where grains are farmed and where the distillery is located. It is a strictly regulated alcoholic beverage. The type of grain, distillation process, and aging conditions all contribute to its unique characteristics. While whisky-making traditions vary across regions, the core process remains the same, requiring precision, patience, and expertise.

At its core, every whisky, it has grain (barley, corn, wheat, and rye), water, and yeast. For Scotch whisky, it must contain malted barley. Each component plays a vital role in shaping the spirit’s final taste and texture. Water is considered an essential factor in making good whiskey. It should be clean and free from impurities such as iron. The Scottish pride themselves on their water source as it is the cleanest in the world, making Scotch whisky have a unique taste and purity. The grains are inspected and cleaned to remove all unwanted foreign particles. The kind of grain used varies with the type of whiskey being made, though all whiskies contain some amount of malted barley needed to start the fermentation process. Different grains have different sugar content levels, which influences the sweetness of various whisky. For instance, corn whiskey is sweeter than rye or wheat whiskey since corns have higher sugar content. Every distillery maintains a reliable supply of yeast.

Note:

• Corn adds sweet flavors and yields higher alcohol content than other grains.
• Barley adds a rich malty, and toasty taste.
• Rye adds a more pronounced spicy and earthy flavor.
• Wheat is neutral, creamy, and soft, and it gets more flavors from the oak barrels used.

Although the primary methods for producing whisky are very similar, it is worth noting that each distillery has its unique specifications, layout, and general presentation, priding themselves on their successes and uniqueness. Here is the general process of making this much-loved spirit from raw grain to bottled whisky. 

The process begins with malting, where barley is produced by moistening the best quality barley and then spreading it out on malting floors to germinate. The malt is regularly turned to prevent the buildup of heat. During this process, enzymes are activated, useful for converting the barley's starch into sugar. After the barley's germination occurs, which takes about six to seven days, this process is interrupted by putting the malt into the kiln for drying using heat, thereby halting germination. The drying heat is kept below at around 70°C to avoid destroying the enzymes. During this stage, peat may be added to the fire to impart smoky flavors.

The mashing process consists of mixing cooked grain with malted barley and warm water. The grains are crushed to break down the cellulose walls that contain starch granules and make the starch more available for enzyme action. The dried malt is ground into a grist or coarse flour, put in a large tank called a mash tun or tub, and mixed with hot water. The water is added in 3 stages, with each stage getting hotter. The mash is stirred, allowing enzyme in the malted barley converts starch in grains into sugars. A sweet sugary liquid known as mash or wort (if strained of solid particles) is produced and ready fermented.

The fermentation takes place in giant vats, usually called washbacks. In Scotland, it is generally closed and open in the United States. The mash/wort is cooled and transferred to the fermentation vessel. Yeast is added to begin fermentation. The living yeast organisms convert the sugars in the mash/wort to alcohol. The fermentation length varies from distillery to distillery, which may take 2 to 4 days, depending on desired characteristics. The different fermentation times, temperatures, and yeast strains contribute to diverse flavors of the whisky. Primarily, fermentation ends when there is no more sugar for the yeast to transform, and the alcoholic concentration rises too high. The resulting liquid is called distiller's beer or wash. Wash has an alcohol concentration of around 6%-10% ABV, which is excellent for beer, but not for whisky.

The distillation process takes place in a still vessel usually made of copper. This process increases the liquor alcohol content and brings out volatile components, both good and bad. The distillation temperature and other factors determine the proportions of water, alcohol, and other substances called congeners in the final product. This process also helps to strip spirits of unwanted flavor and aroma compounds. The two most common types of distilling stills are pot stills and column stills, which function differently. With either method, the initial distillation product known as low wine is distilled a second time, and a new product known as high wine or new whiskey is produced. The new whisky contains about 70% alcohol. If it contains above 95% alcohol, it is known as neutral grain spirit. This neutral spirit is often used to add alcohol without adding taste during blending.

Pot still distillation

In some mysterious way, the still pot's shape affects the character of the individual malt whisky. It is usually used in the production of malt whiskies, though not always. Pot still distillation is a batch process. Some styles of whiskies use double-distillation, while others are distilled three times. The wash/distiller's beer is put into the first still, often called the low wines still, where the still is heated just below the water boiling point. The alcohol and other compounds vaporize, passing over the still neck into either a condenser or water-cooled copper tube called a worm, where the vapor is condensed into a liquid. The worm is a large copper coil immersed in cold running water, which condenses the vapor into a liquid. The resulting liquid, which is about 20% ABV, goes into the second still, or spirit still, and the process is repeated. After this, a third distillation can occur, resulting in a final liquor with about 60%-70% ABV. The distiller may discard or reserve a certain amount of liquor at the beginning and the end of the run referred to as heads and tails. This is due to their unwanted flavors and aromas. The rest, known as the heart, goes into barrels. Pot stills are often used to make whiskey in Scotland and Ireland. France uses pot still process in making brandy.

Column still distillation

Column stills are also known as continuous distillation or Coffey stills. In this process, alcohol is distilled continually rather than batch by batch. This process is mostly used to produce American whiskey, rye whisky, and grain whiskies. Most modern distilleries use a column still. The column still works efficiently and continuously, eliminating the need for the pot still batch process. It consists of a tall cylindrical column filled with a series of perforated plates. The wash/distiller's beer is fed into the column still at the top and starts flowing downwards, passing through a perforated plates series. Steam enters the still from the bottom. Hot steam rises from the still bottom, interacting with the beer as it flows down through the plates, separating the solids and unwanted substances. The lighter alcohol vapors are pushed up and directed into a condenser and condensed into a liquid. When the vapors hit the plate, they condense, eliminating heavy substances like congeners and increasing the alcohol content. Column stills can produce a 95% ABV spirit, although most whiskies are distilled to lower proof.     

Whisky maturation is the time between distillation and bottling. Whisky aging is a complex process and takes place in the cask, and unlike wine, whisky does not mature further once bottled. During aging, the whiskey interacts with the barrel, changing the end product's chemical composition and taste. While aging, the whisky goes through; extraction, evaporation, oxidation, concentration, filtration, and coloration processes that define eventual whisky flavor. The maturation imparts whisky smoothness, flavor, and each whisky's distinctive characteristics. Whisky color ranging from pale, light gold to rich amber is influenced by the type of cask used and length of maturation.

Scotch whiskeys are aged in cool and wet conditions so that it absorbs some moisture and become less alcoholic. American whiskeys are aged in warmer and drier conditions to lose water and become more alcoholic. By law, 'Scotch whisky' must be aged in oak casks for a minimum of 3 years but can rest in wood for longer. Whiskey is aged in wooden barrels made from charred white oak. This is so because white oak is one of the woods that can hold a liquid without leaking and allows the water in the whiskey to move back and forth within the wood's pores, which helps to add flavor. American whiskey must be matured in new charred oak barrels, while for other countries, the type of oak, new or once used cask, is left up to the producer's decision. Some distillers prefer aging their whisky in barrels previously used for other spirits to add additional or specific flavor profiles. A maximum of 2% of the whisky is allowed to evaporate from the cask each year - the 'Angels' Share.

Once matured, the final spirit is bottled at least 40% alcohol by volume (ABV), ready to be shipped to various liquor stores, bars, and restaurants. Glass bottles are used to store mature whiskey since they do not react with it to change the flavors. The glass bottles are moved down to the conveyor belt as they are cleaned, filled, capped, sealed, and labeled. It may be chill-filtered or filtered in another way to prevent it from becoming cloudy when cold water or ice is added.

Good quality whisky is more of whisky-making art skills, careful attention to detail and quality of raw materials than science. However, the whisky maker needs to take some precautions to realize the desired high-quality whisky brand. To realize the desired whisky quality, the master distiller must ensure;

• The water used is clean, sourced from the appropriate natural source, and filtered to make it free from organic matter.
• The grain should be clean and screened to eliminate unwanted materials or low-quality grains.
• The yeast is carefully grown to avoid any possibility of contamination by other microorganisms.
• The distillation temperature is closely monitored with thermometers in the boiling liquid.
• During aging, experienced tasters should evaluate a sample of whiskey to determine if it is mature.
• Master blenders supervise the blending process to produce a final product with the desired characteristics.