Malt Whisky Production Plants
Manufacturing of malt whisky is by blending of malt spirits.
The process of manufacturing malt spirits involves
- Malting
- Brewing
- Fermentation
- Batch distillation
Malting
Fresh barley crop is received and stored in barley godown. Before taking in process it is graded and screened and taken to steeping vessels where it is soaked in water. After soaking it is transferred to Germination box where moisture is retained. Warm air by burning Peat is circulated to start germination. Enzymes present in the grain get activated. Just when the grain starts sprouting, process is stopped by taking the germinated grain to kiln where hot air is used to dry it. Now this dried grain is called malt. It is again screened and stored as malt.
Brewing
Dried malt is ground and transferred to mash tun, a vessel with false bottom. Hot water is added then by keeping the mass under thorough mixing. Sugar is extracted from grain and liquid is taken to lauter tun. Solid residue is washed using hot water to remove all sugar and grain is removed from system as spent grain.
Liquid from mash tun is filtered and cooled. Cooled liquid is called Malt Brew. This is rich in sugar, minerals and enzymes, which is later taken to fermentation.
Fermentation
Malt brew is taken to fermentation and yeast propagated bakers yeast is added to it. Temperature in the fermenter is controlled at 30 degrees C to 32 degrees C and yeast converts sugar into alcohol. Malt brew after fermentation is called wash or fermented wash / beer.
Distillation
Wash is taken to pot still where steam in jacketed or coil is used for indirect heating alternatively a re-boiler is used. Alcohol evaporates faster than water. Alcohol water vapour are condensed in the condenser and condensate is collected in alcohol receiver. Alcohol strength of the condensate is checked regularly and distillation is stopped when condensate alcohol strength is approaching zero. Spent wash is drained and pot still is charged again.
Second DistillationM
Condensate from 1st distillation is taken to another pot still and controlled distillation is carried out.
In this distillation
Heads and tails are mixed or collected in separate receiver. These are partially recycled in pot still by mixing with condensate of 1st distillation in next batch.
Middle fraction or product is collected separately and taken to wooden barrels or casks for maturation.
Matured spirit with specified age is mixed with G. N. S. [grain neutral spirit]. This is called blending. D. M. water is added to adjust strength to desired concentration [reduction] and blended product is taken to bottling section when it is bottled and packed.