By American law, bourbon, or any straight whiskey, may only be distilled to a maximum of 160 proof / 80% abv. In many nations, when rum is made, is distilled to no higher than 90% abv.
There’s a good reason for this ceiling: When one distills a spirit over these percentages then one loses most of the organic molecules that give the spirit its distinctive taste and aroma. The result would be grain neutral spirits (GNS.) When GNS are sold for direct consumption, there’s a label for that – vodka.
Here’s where we run into trouble: some nations allow whisky or rum to be distilled all the way up to 95% abv.
That’s almost identical to the azeotrope- the point at which it literally becomes impossible to distill the alcohol any further, as after that point both water and alcohol leave at the same rate. At this point there’s almost no organic molecules from your base material left, whether grains, sugar cane juice or molasses. Little characteristic aroma or taste remains.
So why do we find some Canadian whisky distillers, and some rum distillers, engage in this practice? I believe that it is only to make large amounts of very cheap product.
Many Canadian distillers make a base whiskey that is distilled to a very high abv but they sell it only after blending it with a much lower distilled ABV whiskey. And for many Canadian whiskeys, after also adding wine, caramel coloring, or other flavors.
Many rum distillers make a rum distilled to a very high abv, but again, they sell it only after blending with much lower distilled abv rums, or adding large amounts of sugars, and caramel coloring. Although I do recognize that some funky rums indeed may be improved by distilling them above the 160 proof that I mentioned earlier.
Fionnán O’Connor writes:
When you strip away the marketing bull, the higher the alcohol content the closer you come to pure ethanol and the less flavour affecting compounds resultantly remain. Within a safe margin (traditional irish pot distilling, whether double or triple, will likely kick around the 70-80% range), this could allow you to select or prioritise certain congeners over others of course and create all kinds of diverse distillates but when you hit something like 95% in a column still, you’re not really retaining too many fingerprints off the fermented source.
For example, if you distilled a mash of malted barley to 70% and a mash of wheat to 70% under the same conditions, they would obviously taste strikingly different as they’d be dragging a lot of their fundamentally different origins behind them. If you distilled them to 95%, however, there might be a few nuanced differences but they’d be a whole lot more like each other as so much of their composition is just alcohol itself.
What are your thoughts on this?
Here you can check out our reviews of bourbon, Scotch, Irish whiskey, Canadian whiskey, ryes or flavored whiskys. We have articles on science & health, and a plethora of other topics. Feel free to learn more about me, Distilled Sunshine.