The Mack brewery in Tromso, Norway, said a manufacturing flaw created bacteria leading to a buildup of lactic acid in its Isbjorn, or "Polar Beer" brand, giving it an aroma of sulphur and rotten eggs. The newspaper Harstad Tidende reported Thursday tens of thousands of cans of the "fart-smelling" beer had been sold before the decision to recall the product.
"These bacteria are not dangerous. They are normally used in acidic milk products, such as yogurt, but can give an unpleasant smell and taste in beer. The smell can be like anything from lemon and vinegar to rotten fish. It is something caused by, among other things, decomposition of the proteins in the beer," Mack director Roger Karlsen told the newspaper.
The beer was produced over a two-day period in July.