Some cough syrups are enough to highly elevate the level the breathalysers detect, as well as even mouth washes or sprays, etc. That is why in most states in the US the indication of being over the limit with a breathalyser will not hold up into court, and why they do you officially book you for them. That just is a good indication as to when to take people back and do a more detailed blood test.
So yes, just a ethanol candy would work.