Pilsner yeast, the well-known micro-organism that brewers use every year to make hundreds of billions of litres of pilsner and other lagers, came into being 500 years ago through an accidental encounter between two species of yeast. The yeast strains now used to brew pilsner can all be traced back to that time. This is the conclusion reached by TU Delft researchers based on extensive DNA analysis. Read the article