This is really a postscript to my post of earlier today, but it may be noted that a brand of vodka sold at the LCBO, Silent Sam, recalls 19th century distilling when the term “silent spirit” was devised.
The term was not just Canadian, it was used in Britain and the U.S. as well. As this 1883 English article states, “silent spirit” meant a spirit of such purity that it was silent as to its origins.
In turn this meant, you couldn’t tell if it was distilled from rye, wheat, sugar, corn or anything else capable of being fermented and distilled into a spirit. The distillation was so thorough that the only compounds left, practically, were ethanol and water. And all ethanol tastes the same regardless of source.
In traditional whisky distilling and ditto for brandy, rum, and the other traditional spirits, chemical compounds other than ethanol are allowed to remain which speak of the materials they derive from. Hence some rum tasting of molasses, or tequila of cactus, etc. (Rye sometimes tastes like soap or pine, not sure why, but it does).
Silent Sam, from Diageo/Schenley, was the kind of spirit Charles Richardson was referring to when mentioning how Canadian whisky was confected in the last part of the 1800s. It must be recalled though that all Canadian whisky must be aged in wood barrels at least three years, so the silent spirit part is modified by such wood and air contact.
Some distillers consider that notwithstanding the great purity their neutral spirit, or grain whisky as it is known, achieves, there is still some flavour contribution from the spirit, vs. only the wood tannins and sugars it acquires from barrel aging. This could result from trace amounts of congeners – higher alcohols, acids, esters – which remain in the spirit even at 94-95% abv.
This is possible, but in my view, this extra flavour is minimal. The real flavour comes, apart from wood tastes, from the straight rye or other straight whisky added in blending. That is why they are called “flavouring whisky”, it is a distillers’ term, not mine or anyone else’s.