Sorry to bore everyone rigid re Glendronach (again), but here's a short and sweet article re the more general subject of Direct-Firing:
http://themaltdesk.blogspot.dk/2013/05/glendronach-1992-16yo-dk-exclusive.html
Please note that Springbank/Longrow/Hazelburn and Mortlach still use Direct-Firing to a greater or lesser extent.
Any thoughts?
P.S. Another Scots distillery uses direct-firing but I've forgotten which one! Does anyone out there know?