As reported by The Telegraph, the whiskey-based biofuel is made using draff, the husk residue of grains used in fermentation, and pot ale, the residue of fermented wort left in a still after distillation. Scotland, a nation known for it's world-renowned whiskeys, happens to produce around 800,000 tons of draff and over half a billion gallons of pot ale annually. "We physically poured a bottle of [alcohol] butanol into the car, but the scale of this could be huge," Professor Martin Tangney, the founder and president of Celtic Renewables, told The Telegraph. "The test run shows that we know we could make it," said Tangney. "The blueprint just needs to be replicated."