samples were from different bottles/cans, typically from different retailers. A wide range of beer types or styles was sampled (Fig. 1a),including ales (64 samples including 41 beers labeled as ales, seven bitter beers, six India Pale and ten stout/porter ales), LAGERS (60 samples,58 named as lager and two specifically classified as pilsner) and lambics (n=4). The sample beers originated from 13 different countries(Fig. 1b)and were classified into four large groups.