It is because there are some strict criteria that whisky must meet before it could be called Single Malt Scotch.
These criteria make the mass-production of Single Malt Scotch difficult, making it so valued.
Criterion 1: The primary ingredient in making a whisky is grain, and in Single Malt Scotch, that grain can only be barley.
In one year, the world production of barley is 1/7th of corn and 1/5th of wheat, so barley is rarer than these mass grains.
Criterion 2: Single Malt Scotch must be distilled in a single distillery in Scotland, and that is where Single comes from and not because it is made from a single grain.
World’s biggest distillery Glenfiddich (pronounced as Glen-fiddikhh) distills 10 million litres of Scotch in a year, and Scotland has only 120 distilleries, and all of them can’t be doing single malts; so there is not a lot being produced each year.
On top of that, the bottle in your hand having a unique physical location (the bottle that you hold was distilled at one physical location traceable on the map) gives exclusivity that blended whiskies can’t boast about.
Criterion 3: The distillation must happen in Pot Stills, an apparatus for distilling alcoholic spirits.
Pot Stills are considered ‘traditional’ and have a production capacity that is significantly lower than the modern, industrial-scale Column Stills.
So, limited pot still outputs are considered hand-crafted and ‘artisanal’.
Criterion 4: Single Malt Scotch must be aged in oak casks (capacity not more than 700 litres) for at least three years before it can be bottled.
Alcohol is said to evaporate at a rate of 1% each year, so ageing also reduces the quantity making it even dearer.
