Why does whisky mature faster in a warm climate?

Higher temperatures speed up the exchange between the whisky and the oak of the cask, so a cask gives up in a few years what takes much longer in Scotland.

When it is warm, the spirit expands and penetrates deeper into the pores of the wood, so that it comes into contact with more wood surface. On cooling, it withdraws and takes dissolved substances from the wood with it. In India, Taiwan, Israel and Australia this happens more often and more intensely than in Scotland, where the temperature stays close together all year round.

Whisky Magazine cites a maturation rate for India of roughly three years for every one year of Scottish maturation. A cask in Goa or Yilan therefore works harder on the spirit than a cask in Speyside, over the same calendar time.

In Scotland on average about 2 percent of a cask's contents evaporates per year, whereas in India that loss can rise to 14 to 15 percent.

That loss is called the angel’s share. Paul John Distillery in Goa states 8 to 10 percent per year on its own site. Whisky Magazine arrives at 14 to 15 percent for India and states that after three years about half of the contents of a cask can have disappeared. For Kentucky about 4 percent per year is cited, well over double that of Scotland.

A cask that empties so quickly can only be justified if the spirit also matures quickly. Maturation of fifteen or twenty years, quite normal in Scotland, often leaves too little spirit to bottle in the tropics.

In a dry and warm climate the alcohol percentage rises in the cask, in a humid or cool climate it falls.

The staves of a cask act as a membrane through which both water and alcohol escape. The drier the outside air, the more water the cask can lose, so that the share of alcohol in what remains increases. Casks in Kentucky therefore come out of the warehouse stronger than they went in.

In Scotland’s damp, cool air, more water actually stays in the cask and proportionally more alcohol disappears. For Scotch whisky a drop of about 0.5 percent alcohol per year is often cited. Heat alone therefore does not determine which way the percentage goes; humidity does.

Age measures time and not ripeness, and because the pace differs greatly per climate, a four-year-old whisky from the tropics can be further along than a ten-year-old Scotch.

The Scotch Whisky Regulations 2009 require at least three years of maturation, exclusively in Scotland, in oak casks of at most 700 litres, and at least 40 percent alcohol in the bottle. These British rules apply only to whisky matured in Scotland. Whisky from India, Taiwan, Israel or Australia is not covered by them and follows the rules of its own country.

If a Scotch bottle carries an age, then according to the Scotch Whisky Association's guidance only the age of the youngest whisky in that bottle may be stated, in whole years. A number on the label is therefore a lower limit in time and no measure of what the cask has done.

The shop at Brink 2 in Bathmen has 105 bottles of whisky from India, Taiwan, Israel and Australia, alongside 2,861 bottles from Scotland.

The breakdown is 45 bottles from India, 41 from Taiwan, 11 from Israel and 8 from Australia. The whole whisky range comprises 4,017 different bottles, so the warm countries make up a small part of the whole.

The largest brands in that group are Kavalan with 37 bottles, Amrut with 18, Paul John with 17, M&H with 7, Rampur with 7, Hellyers Road with 6 and Milk & Honey with 4 bottles.

Wilt u weten hoe een jonge whisky uit een warm klimaat zich verhoudt tot een oudere Schotse, loop dan binnen aan de Brink 2 of bel ons. Wij zetten de flessen voor u naast elkaar en leggen uit waar het verschil vandaan komt. Wij verkopen geen alcohol aan personen onder de 18 jaar. NIX18.