At what threshold is acetaldehyde detected in beer?

Acetaldehyde is a compound that can form during fermentation and is often associated with the presence of yeast. It has a notable impact on the flavor profile of beer, where it is perceived as having a green apple or fresh-cut grass aroma. The sensory threshold for detecting acetaldehyde in beer is generally around 10 parts per million (ppm).

At this concentration, tasters may begin to notice its effects, which can detract from the overall quality and character of the beer. Recognizing the importance of controlling levels of acetaldehyde during the brewing process is crucial, particularly in styles that are sensitive to off-flavors. Lower fermentation temperatures, proper yeast management, and allowing for sufficient time for yeast to complete fermentation are all practices used to minimize acetaldehyde levels.

Understanding the threshold for acetaldehyde is essential for brewers and cicerones alike, as it helps in assessing the quality and consumer acceptability of beer. In this context, the other options represent levels that exceed the typical detection threshold, thus making them less relevant for understanding when acetaldehyde becomes noticeable to consumers.