The Lowland Scots for smoke is 'reek' -- Edinburgh, with its smoking tenements, was once known as 'Auld Reekie' -- and after 1824 'peatreek' came to be used to describe illicit homemade hooch, no doubt a reference to the smoky aroma and flavour of such whisky. In the remote Highlands, where peat was the main (in some places, only) source of domestic fuel, the kilning of malt was done entirely over a peat fire. (p. 105)
So peatreek is synonymous with moonshine, not a descriptor of the aroma of a peaty whisky. In light of this fact, consider Jim Murray's review of Dalwhinnie 15 year old, as quoted in Kevin Erskine's Instant Expert's Guide to Single Malt Scotch:
Nose: Sublime stuff: a curious mixture of coke smoke and peat-reek wafts teasingly over the gently honied malt. (p. 60)
So is Jim Murray aware of what peatreek traditionally has been, meaning that he's using the phrase in his review as an amusing counterpoint to it, or does he assume that peatreek refers to peaty aromas in a whisky?