Production process of Whisky - Online Biology Notes

Whisky:

It is a distilled alcoholic beverage obtained from fermentation of grains followed by distillation and ageing in white oak barrel for 3-4 years.
Primarily, barley is used but other grains such as corn, wheat, oat & rye are also used.
Whisky may be malt or non-malt.
The concentration of ethanol in whisky is not less than 40%.
Whisky is usually colored with the addition of caramel (burned Sugar).
Whisky production was first begun on Scotland.
But some believe that it started on Arabs & Greek.
Whisky production was supposed to be started first by Irish 1000 years ago.
But written records suggest that, it was after 1494.
Microbiology – Improved strains of Saccharomyces Cerevisiae.
Biosynthesis:
- Glucose —–> Pyruvate —–> Acetaldehyde —-> Ethanol

Basic substrates used for whisky production are water & grains.
The water should be free from hazardous material, pesticides, toxic chemicals & heavy metals.
But it should have high DO value.
The water containing lime is considered good for whisky production.
The basic ingredients for whisky include barley, oat, ray, malt etc. but it must be free from fungal infection.
Beside those substrate other things needed for whisky production are caramel mix (burnt sugar + others).
According to substrates used, whisky are of:
- Straight whisky: No added ingredients i.e. non-blended
- Blended whisky: Added with different ingredients and sherry (wine)
Barley—-> malted cooked at 100^oC for 3hrs/150^oC for 1 hr
Other grains —-> grounded without malting —-> cooked ta 100^oC for 3hrs/150^oC for 1 hr
Cooking liquify starch and break cellulose wall of grains.

Malting is essential for enzyme activity.
In Scottish whisky, barley germination heating is provided with hot air which is produced from peat burning.
Peat is soft carbon rich substance when plant matter decomposed in water.
It provides characteristics smoky flavor to Scottish whisky.
But, in other countries, hot air is produced by coal burning.

The malted barley is grounded and mixed with cereals and finally subjected to controlled heating with overall temperature 40-85^oC for several days.
During heating alpha-amylase is converted into beta amylase.
After mashing it is filtered to obtain wort.
It is optimized for total sugar content (TSS)= 20-30%.

Mash/wort (TSS=20-30%) —> pH adjusted (3.5-4.5) —-> close fermenter (mostly used)
Mash/wort (TSS=20-30%) —–> pH adjusted (3.5-4.5) —–> open tank fermenter (require more time, more chance of contamination, more chance of loss of ethanol.

Now the ethanol is evaporated at 78-80^o C.
In Scotland, distillation is carried out in copper plant or stain less steel.
Distillation is carried out to obtain 95% ethanol.
The ethanol should be free from congeners.
Congeners are the extra things that produces bad flavors such as aldehyde, ketones & other volatile substances.
It is overcome by production of high % or concentrated ethanol.
Hard/High wine is produced.

The high Wine is diluted with addition of water to obtain the solution with alcohol content 50-65%.
In the Scotland, the diluted ethanol is kept inside white oak barrel and mouth of the barrel is sealed and kept in cool & wet condition.
Whereas in American whisky, the ageing is done in warm and dry condition.
During ageing, the congeners, esters, sugars, and alcohols react together to form special type of aroma.
Ageing is conducted minimum for 3-4 years & maximum up to 10-15 years.

In blending, appropriate proportion of different whisky of previous batch is mixed with the aged whisky.
At the same time, the appropriate proportion of Sherry port & other things are also mixed to develop flavors.
Finally, caramel mix is added in appropriate amount to develop a suitable color.
Finally, it is checked by testing with master blender.