What is the primary compound associated with oxidation in beer?

The primary compound associated with oxidation in beer is trans-2-nonenal. This compound emerges during the oxidation process and is largely responsible for the cardboard-like or sherry-like off-flavors that can develop in aged or improperly stored beer.

As beer oxidizes, various reactions lead to the formation of trans-2-nonenal, which has a notable aroma reminiscent of stale or oxidized flavors. It is more pronounced in beers that are not packaged properly or exposed to light or oxygen over time. This compound becomes particularly relevant when discussing the staling of beer, marking it as a key consideration when evaluating beer quality and freshness.

While other compounds listed, such as diacetyl and acetaldehyde, can contribute to off-flavors, they are not directly tied to the oxidation process in the same way. Diacetyl is more commonly associated with fermentation by certain yeast strains and imparts a buttery flavor, while acetaldehyde is typically a byproduct of yeast metabolism during fermentation, causing a green apple flavor. DMS, or dimethyl sulfide, is often associated with certain styles of beer and can impart a sweet corn or vegetal flavor when present.

Therefore, trans-2-nonenal stands out as the primary compound connected with the