The difference between a beer and a lager lies primarily in the fermentation process. Ales and lagers are two major classifications of beer, each with its own distinctive characteristics.
Ales are fermented with top-fermenting yeast at relatively warm temperatures, typically around 60˚–70˚F (15˚–21˚C). This type of yeast, known as Saccharomyces cerevisiae, rises to the top of the fermentation vessel during the fermentation process. Ales tend to have a more robust and complex flavor profile compared to lagers. They often exhibit fruity, spicy, and sometimes even floral notes. Ales also tend to have a fuller body and a richer, more pronounced malt character.
On the other hand, lagers are fermented with bottom-fermenting yeast at colder temperatures, usually ranging from 35˚–50˚F (2˚–10˚C). The yeast used in lager production, called Saccharomyces pastorianus, sinks to the bottom of the fermentation vessel during fermentation. Lagers are known for their clean and crisp taste, with a smooth and refreshing quality. They typically have a lighter body and a milder, more subtle flavor profile compared to ales.
The fermentation temperature plays a crucial role in determining the characteristics of the final beer. Ales, fermented at warmer temperatures, allow the yeast to work more quickly, resulting in a shorter fermentation period. This can contribute to the fruity and estery flavors often associated with ales. In contrast, lagers, fermented at colder temperatures, have a longer fermentation period, which helps to produce a cleaner and more balanced flavor profile.
Another factor that sets ales and lagers apart is the type of yeast used. Ales use top-fermenting yeast, which is more tolerant of higher temperatures and tends to produce more complex flavor compounds. This yeast type ferments more quickly and is often used for styles such as pale ales, IPAs, stouts, and porters.
Lagers, on the other hand, employ bottom-fermenting yeast, which thrives in colder temperatures and takes longer to ferment. This yeast type produces fewer flavor compounds, resulting in a beer with a cleaner and crisper taste. Lager yeast is commonly used for styles such as pilsners, helles, bocks, and Märzens.
The primary difference between a beer and a lager lies in the fermentation process. Ales are fermented with top-fermenting yeast at warmer temperatures, resulting in a more robust and complex flavor profile, while lagers are fermented with bottom-fermenting yeast at colder temperatures, producing a clean and crisp taste. The choice between an ale and a lager ultimately depends on personal preference and the desired flavor experience.