The Basic Whisky Brewing Process
Basic Whisky Brewing Process
1. Soaking
Barley is soaked in water to promote germination. Although commercial enzymes can be used as saccharifying agents, sprouted barley remains the mainstream choice.
2. Germination
The soaked barley is transferred to a germination chamber and spread evenly for sprouting. Modern germination drums, resembling giant washing machines, allow better control of temperature and humidity.
3. Drying
Germinated barley, known as “green malt,” is dried at 60–70°C to stop growth while preserving enzymes needed for saccharification. Traditionally, Scottish distilleries use peat as fuel, giving whisky its smoky, peaty flavor.
4. Milling
The dried malt is ground to release starch granules for saccharification. Malt whisky uses 100% malted barley, while grain whisky uses corn, wheat, rye, or unmalted barley, with about 20% ground malt added as a saccharifying agent.
5. Mashing
The ground raw materials are mixed with water to form a mash. Saccharification takes place at 60–65°C. Water quality greatly influences the style of whisky, making the water source a key element in every distillery.
6. Fermentation
After cooling the mash to 20–30°C, yeast is added to start fermentation. Within about 3 days, it produces a wash with around 7% alcohol.
7. Distillation
The wash is heated based on alcohol’s lower boiling point (around 80°C). Alcohol and aromatic compounds evaporate before water and are condensed back into liquid. Whisky is usually distilled 2–3 times to produce a new spirit at about 70% ABV.
8. Maturation
The new spirit at 70% ABV is diluted to around 65% before entering oak casks. The barrel absorbs impurities, imparts color and flavors, and allows slow oxidation in a micro-oxygen environment, developing complexity over time.
9. Blending & Bottling
Each cask matures differently, so blending ensures a consistent house style. Blenders may mix casks from different batches or even different years, diluting to around 40% ABV. Some distilleries also release single cask whiskies without blending.
