It’s a common first world problem at summer music festivals: the bar queues are long, the exclusive corporate beer on offer is not just overpriced: it also tastes like, well, pee.
Danish farmers have taken things to the next level with an innovative process called "beer-cycling": brewing a new beer using urine collected from guests at the popular Roskilde festival.
In 2015, Denmark’s agriculture and food council collected 54,000 litres of urine from festival-goers. The urine was then transformed into fertiliser, yielding 11 tonnes of malting barley.
After harvesting and brewing, the beer-dubbed “Pisner” – not Pilsner – will be released on the market in June.
"When it comes to circular economy, Danish farmers are some of the best in the world," said Karen Hækkerup, CEO of the Danish Agriculture and Food Council. "If you can brew a beer with urine as fertiliser, you can recycle almost anything."
Though urine is practically sterile when it comes out of the body, Danish brewers insist there is no actual urine in the beer. However urine is full of nitrogen, potassium and phosphorus, the same ingredients found in regular fertiliser.
After Roskilde visitors “donated” their urine, a novelty that cut down on random peeing in the bushes, some 100,000 festival-goers can, two years on, now taste the result of their collective efforts.
Fertilising potential
Nordic scientists have spent years exploring the possibility of tapping the human bladder for its fertilising potential. The typical western adult urinates about 500 litres a year, enough to fill three regular bathtubs, and more than enough to fertilise their own brewing hops.
Five years ago, Finnish scientists published a scientific paper detailing their successful experiments using human urine to cultivate beetroot.
The urine-fertilised beetroots were up to 27 per cent larger than traditionally-fertilised vegetables, the scientists said, had identical nutrient value and were indistinguishable from regular beets in blind taste tests.
Though experts are convinced that urine has a bright future in agriculture, two hurdles have to be cleared before wider usage is possible: first, overcome taboos about recycling urine; second, remodel sewerage systems to collect and transport liquid waste for processing.
With 60,000 bottles of Pisner beer ready, Copenhagen microbrewer Nørrebro Bryghus said it remains intrigued by sustainable beer contributing to a circular economy.
Added executive director Henrik Vang: "Basically it's a cool project."
