<<Disclaimer: Verify this information before applying it to your situation.>>

Almost all responses to the question of whether or not Scotch whisky is
gluten free were that it is GF with many responses coming from reputable
sources such as chemists or distillers.  The only responses different to
this were a small number where people were unsure.  So, while individual
should decide for themselves, all evidence seems to point to all Scotch
whisky being GF.