The complex comprised what was at the time the largest grain distillery in Europe, 'Dumbarton' alongside two still houses that in time produced two different malt whiskies. These were Inverleven and Lomond.
Inverleven malt was made with the two conventional stills, while in 1959 the distillery installed the first example of what is now known as a 'Lomond still', which incorporated a cooling apparatus like a rectifier in the head of the still to encourage reflux and produce a lighter spirit more attractive to the American market. The malt made by this still was called, unimaginatively, 'Lomond'.
Lomond stills were also installed for this purpose by Hiram Walker at Scapa, Glenburgie (producing Glencraig) and Miltonduff (producing Mosstowie)later on in the 1950s, but the ones at Glenburgie and Miltonduff were removed in 1981.
In 1987 Hiram Walker was taken over by Allied Brewers, who shortly afterwards were to become Allied Distillers, who then merged to become Allied Domecq. The Dumbarton complex was run into the ground and eventually grain production for Ballantine's was switched to Strathclyde as Dumbarton was too difficult to modernise: the stills went up through a concrete floor, making structural alterations somewhat problematic.
Production of Lomond had stopped in 1985, and Inverleven was to follow suit in 1991. The Dumbarton distillery carried on making grain for several years (25 million gallons in 2001), but was finally mothballed in 2002 and the buildings have now been demolished to make way for housing. It would seem that the famous "Scotch Watch"gaggle of 100 geese that 'guard' the Ballantine's bonded warehouses in Dumbuck are rather more effective in advertising campaigns than against faceless multi-national corporations.
During their operating lifetimes all the production at Dumbarton, Lomond and Inverleven went into Ballantine's and there were never any official bottlings of either of the single malts. However, enterprising independent bottlers have released a handful of bottlings of Inverleven, which has been described by Michael Jackson's Malt Whisky Companionas "Perfumy, fruity, oily. With a summer salad when young; with nuts at Christmas when older."