What fermentation-derived flavor commonly appears in ales but not lagers?

Esters are a group of compounds produced during fermentation as a result of the interaction between yeast and sugars. They are characterized by fruity and floral flavors and aromas, which can enhance the overall profile of ales. Ale yeast, typically top-fermenting, operates at warmer temperatures than lager yeast and tends to produce a greater variety of esters during fermentation. This is particularly noticeable in styles like pale ales, IPAs, and Belgian ales, which often showcase fruity notes ranging from banana to apple and other desirable characteristics derived from esters.

In contrast, lager yeast, which is bottom-fermenting and works at cooler temperatures, produces fewer ester compounds. This results in a cleaner and crisper flavor profile typical of lagers, focusing more on malt and hop characteristics rather than fruity esters. Therefore, esters are commonly associated with ales and significantly contribute to their unique flavors, distinguishing them from lagers that exhibit minimal ester presence.