Have you ever cracked open a bottle of beer and found that it tasted like wet cardboard? In this video we go over the common beer off flavours: wet cardboard, skunky, sweet, and moldy. A wet cardboard flavour in beer is caused by beer oxidation. Oxygen reacts negatively with molecules in the beer to produce unwanted stale cardboard flavours. As for skunkiness, that is caused by UV rays breaking down the alpha-acids in beer hop. Overly sweet beer can mean that there was a stuck fermentation and the yeast was unable to convert the sugars in the wort into alcohol. Moldy-tasting beer can be the result of mold in the grain used to make the beer. So let's dive into beer off flavors in beer!