Alex raised an eyebrow as he took a sip. The whisky hit his palate with a robust, spicy flavor, followed by notes of vanilla, oak, and a hint of smokiness. He was impressed.

You will sometimes see whisky labeled at or 54.5% . This refers to "Navy Strength" or "Gunpowder Proof." Historically, the British Royal Navy tested rum (and later whisky) by mixing it with gunpowder. If the gunpowder still ignited, the spirit was "proof" (meaning it had enough alcohol to burn). That threshold was roughly 57% ABV (4/7ths alcohol by volume). Today, a few distilleries release "Navy Strength" expressions as a nod to history.

How does a whisky change from 70% new make to 40% bottled?

Here is everything you need to know about the alcohol percentage of whisky.

Suddenly, Mr. MacTavish leaned forward, a twinkle in his eye. "Alex, I have another surprise for you. We've been bottling a limited edition of Experimentum 1418, diluting it to 46% ABV. Would you like to try it?"

Even more exclusive than Cask Strength, these are bottles drawn from a single barrel. Because different barrels have different evaporation rates (the "Angel's Share"), the ABV can vary wildly from bottle to bottle—one might be 48%, another 58%.

It was a chilly winter evening in the Scottish Highlands, and whisky connoisseur, Alex, had just arrived at the Glenmoriston Distillery. He had been invited by the master distiller, Mr. MacTavish, to taste a special batch of whisky that had been maturing in a mysterious cask for over 20 years.

The evening wore on, with Alex and Mr. MacTavish delving deeper into the world of whisky and exploring the nuances of Experimentum 1418. For Alex, it was a memorable night, one that would stay with him forever, much like the allure of that mysterious cask and its whisky with an alcohol percentage that dared to be different.