: Often called "top-fermenting" yeast because it rises to the surface during active fermentation. It thrives at warmer temperatures (typically 15–24°C / 60–75°F) and produces fruity esters and spicy phenols, which are characteristic of IPAs, stouts, and Belgian ales.
Brewing yeast acts as the biological engine of the fermentation process, transforming the sugary liquid known as into beer. This single-celled fungus consumes malt-derived sugars—primarily maltose and glucose—and converts them into ethanol (alcohol) and carbon dioxide (CO2) through a process called alcoholic fermentation.
For those looking to dive deeper into yeast management and fermentation science, several definitive guides are available:
The two most common species used in modern brewing are distinguished by their fermentation behavior and temperature preferences:
: The yeast population explodes, rapidly consuming sugars and producing the bulk of the beer’s alcohol and CO2.
Beyond just producing alcohol, yeast contributes hundreds of secondary metabolites, such as esters and phenols, which are responsible for the complex aromas and flavor profiles unique to different beer styles. Primary Types of Brewing Yeast