Analysis of 100-Year-Old Beer Originated from the Czech Republic

Three bottles of different beers were found in 2015 during a reconstruction of the brewery of the Raven Trading s.r.o. company in Záhlinice, Czech Republic. Thanks to good storage conditions, it was possible to analyze their original characteristics. All three bottles contained most probably lager type beer. One beer had sulfuric and fecal off-flavors; it was bright with the original extract of 10.3° Plato. The second beer, with an original extract of 7.6° Plato, was dark and very acidic, resembling Lambic. DNA analysis proved the presence of Dekkera bruxellensis, which corresponded to its chemical profile (total acidity, FAN, ethyl acetate, total esters). The third beer contained traces of carbon dioxide bubbles, was light brown and slightly bitter, with an original extract 10.4° Plato. Because it obviously underwent a natural aging process, sweetness, honey, and fruity off-flavors were detected and transformation products of iso-α-acids were found.