What is Single Grain Whisky?

Single Grain Whisky first and foremost must be the produce of one distillery. This is what the "single" bit actually refers to rather than the grain. For, they can be made using malted or unmalted barley, wheat, corn, rye, or any combination of these grains. Most grain whiskies do in fact use malted barley as a base, but add a different grain to change up the flavour profile, otherwise it would just be a Single Malt Whisky instead.

The difference between Single Grain Whisky and Blended Grain Whisky is that Single, as said above, refers to the fact it comes from one distillery. Blended means that the whisky is the result of whiskies from more than one distillery.