Why most whisky is bottled at 40 percent

40% is the legal minimum in most whisky countries

Scotch whisky must be bottled at a minimum of 40% ABV. The same floor applies to whisky sold in the European Union. In the US, whiskey is bottled at no less than 40% (80 proof). Below that line, the drink cannot be sold as whisky in those markets.

So 40% is not where whisky tastes best. It is the lowest strength at which it is still allowed to be called whisky. For a producer selling large volumes, bottling exactly at the floor makes sense, as the next section shows.

Water is added before bottling

New make spirit from a pot still typically comes off at around 65 to 72% ABV. It is usually reduced to about 63.5% before filling into casks in Scotland. After years of maturation it may still be close to 60%. Our guide to reducing whisky to bottling strength covers the process.

Before bottling, the whisky is brought down with clean, demineralised water. Going from 60% to 40% means adding half as much water again as there was whisky. That stretches each cask into more bottles. It also changes the flavour, as we will see below.

Tax is charged on alcohol

In many countries, duty on spirits is charged on the amount of pure alcohol in the bottle. A 700 ml bottle at 40% contains 280 ml of alcohol. The same bottle at 46% contains 322 ml, 15% more. Every extra percentage point is more tax and more whisky used per bottle. For a mass market blend, 40% keeps both down.

In India, excise is set by each state. The way it is calculated varies too. The principle is similar, though: stronger spirit tends to cost more to make and to tax. Much Indian whisky is bottled at 42.8% ABV, a figure that comes from the old British proof system, where it equals 75 degrees proof.

What strength does to flavour

Alcohol carries aroma. Many flavour compounds in whisky dissolve better in ethanol than in water. As you add water, some of those compounds become less soluble and move towards the surface of the liquid, where your nose can catch them. That is why a few drops of water can open up a strong whisky.

Go too far and the effect reverses. The whisky becomes thin and the texture goes. At 40%, many whiskies are pleasant but some lose body compared with the same spirit at 46%. Oily, waxy textures in particular come through better at higher strength.

Strength also changes how heat feels. A cask strength whisky at 58% can numb the tongue. A 40% whisky rarely does.

Why some whiskies sit at 43, 46 or higher

• 43%. Long used for some export markets and for bottlings where the producer wanted a little more body than 40.
• 46%. A common choice for whiskies that are not chill filtered. At around 46% and above, the fatty compounds that can cause haze when chilled tend to stay dissolved, so the producer can skip chill filtration and keep the texture.
• Cask strength. No water added before bottling. Usually 50 to 65%. The drinker adds water to taste.

Below 46%, many producers chill filter, cooling the whisky and passing it through filters to remove those compounds. It keeps the whisky clear when ice or cold water goes in. Critics argue it strips some texture. Our guide to haze when reducing whisky explains the chemistry.

How to use this when you buy

Strength is one of the most reliable clues on a label. A whisky bottled above 40% has usually been made with flavour in mind rather than price alone. That is not a rule, but it is a fair starting point when two bottles cost about the same.

Watch for one trap. Strength and price are linked, so a 46% bottle will usually cost more than a 40% bottle of similar whisky simply because it holds more alcohol and more duty. Compare like with like: the same style, the same distillery where possible. Then ask whether the extra texture is worth the extra rupees to you.

If you drink whisky with soda or plenty of ice, 40% is fine. If you drink it neat or with a few drops of water, try a 46% bottling of a style you already like. The difference in texture can be striking. Training yourself to feel that difference, rather than just the heat, is part of learning to taste.

Your first step

Pour 15 ml of a 40% whisky and 15 ml of a 46% or cask strength one. Taste both neat. Then add water to the stronger one a few drops at a time until it feels as warm as the 40%. Note what changes in aroma and texture at each step. That small exercise teaches you more about strength than any label.

Common questions

Why is whisky bottled at 40%?

It is the legal minimum strength for Scotch, for whisky in the EU and for whiskey in the US. Many countries tax spirits on alcohol content, so bottling at the minimum keeps duty and costs down.

Why is Indian whisky often 42.8%?

42.8% ABV equals 75 degrees under the old British proof system, which many Indian labels still use.

Is 46% whisky better than 40%?

Not automatically, but 46% bottlings are often not chill filtered and keep more texture. Taste both and decide.