What off flavor is a result of oxidation in beer?

Oxidation in beer primarily leads to off-flavors that can be characterized by sensations similar to wet cardboard or a waxy texture. These flavors occur due to the degradation of hop oils and malt characteristics over time, especially when the beer has been exposed to oxygen. The reaction results in the formation of various compounds, including trans-2-Nonenal, responsible for the cardboard-like flavor. This off-flavor is often undesirable, indicating that the beer has aged poorly or has been improperly handled, such as being exposed to light or stored for too long. Understanding oxidation and its effects is crucial for maintaining the quality and freshness of beer.