Great News for Whiskey Drinkers!

http://motherjones.com/blue-marble/2012/03/great-news-whiskey-drinkers


Celtic Renewables founder Martin Tangney does his best mad whiskey scientist. Image by Celtic Renewables.

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.

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Here's how it works: To make Scotch whiskey, you take barley, separate out the sugar, add water and yeast, and ferment it. The result is similar to beer. The next step is to distill the alcohol from that beer in pots. Set it to age in wooden casks, and a few months later, you have whiskey.

The problem is that the process creates a lot of byproduct: First there are the remains of the barley, called draff. And when you distill the alcohol, you're left with a liquid called pot ale, which is hard to dispose of because it contains biological components that can acidify ecosystems, along with traces of copper that are leached from the pots. Celtic Renewables makes a soup out of the pot ale and draff. Then—through a fuel-making fermentation process that was developed during the leadup to World War I but fell out of favor when it couldn't compete with petroleum—the company converts the stuff into biobutanol fuel, animal feed, and acetone.