If you think the only use for Scotch was relishing it, you could soon be proved wrong. A Scottish start-up is exploring ways to turn whiskey by-products into the next-generation biofuel. Each year the Scottish breweries produce 500,000 metric tonnes of a solid waste called draff and 1.6 billion litres of a yeasty liquid called pot ale—together, these by-products account for 90% of the input stock of grain, yeast and water processed. These are either dumped into the sea or used as  low-grade animal feed. Celtic Renewables is fine-tuning a century-old fermentation process for its plant where it will convert draff and pot ale into fuel-grade bio-butanol, which is similar to ethanol, the most used biofuel.
Apart from packing a greater calorific value than traditional petroleum-based fuels, biobutanol can be transferred through pipeplines, something that can’t be done for ethanol. Besides, current internal combustion engine technology is geared to handle any fuel mix with biobutanol while most cars can handle only a 10% ethanol mix. The only catch is that the distillation of bioethanol is a costly process, though many projects are working at bringing these down. But in the context of Scotland, this can be offset by the fact that costs of disposal of the grain sludge and pot ale can be avoided. There is also the potential reduction in environmental costs to consider—while other biofuels rely on crop produce for feedstock, viz. corn, soya,jatropha, leading to denudation of grasslands and forest lands, the Celtics Renewables’ technology will be using the by-product of another industry. So, in raising a toast, it would soon be possible to factor in the good to the environment being done.