A confession: When I wrote about the environmental footprint of various kinds of booze a while back, I was really hoping that whiskey would turn out to be the greenest. That's because it's far and away my favorite alcoholic beverage, whether served on the rocks in a comfy bar or sipped from a flask, campfire-side. What I found, though, is that the production of whiskey and other spirits requires much more energy than wine or beer. This is especially true in boutique distilleries that use old-fashioned pot-style stills, which make delicious whiskey but are pretty inefficient when it comes to energy use. The distilling process also makes a lot of waste. I found myself ruing the day I ever looked into all this. Who wants to feel guilty about booze, for goodness sake?

Imagine my delight, then, when I learned about a Scottish startup that is poised to make whiskey production greener. Celtic Renewables has figured out how to ferment whiskey waste and turn it into biofuel, along with two other useful products.