Lagers are a type of beer that are distinct from ales due to their specific brewing process and use of different yeast strains. What sets lagers apart is their bottom-fermentation method, where the yeast used in the brewing process settles at the bottom of the fermentation tank. This is in contrast to ales, which use top-fermenting yeasts that rise to the top.
The use of bottom-fermenting yeasts in lagers gives them a clean and crisp taste profile. The yeast strains used in lagers also have the ability to tolerate lower temperatures compared to those used in ales. This lower temperature fermentation process is known as “lagering” and typically takes place at temperatures between 7-13 degrees Celsius (45-55 degrees Fahrenheit).
One of the benefits of lagering is that it allows for a slower and more controlled fermentation process. This results in a beer that is smoother and more refined in flavor and texture. The extended cold storage during lagering also helps to clarify and stabilize the beer, resulting in a clear and bright appearance.
Another characteristic of lagers is their typically lighter and more delicate flavor profile compared to ales. Lagers often have a clean and crisp taste, with subtle malt sweetness and a mild hop bitterness. This makes them highly drinkable and refreshing, particularly in warmer weather.
Lagers come in various styles, ranging from pale lagers to amber lagers, bocks, and pilsners, among others. Each style has its own unique characteristics and brewing techniques, but they all share the common trait of being bottom-fermented.
In my personal experience as a brewer, I have found that brewing lagers can be more challenging compared to ales. The lower fermentation temperatures and longer lagering periods require careful temperature control and patience. It can take several weeks or even months for a lager to fully develop its flavors and reach its optimal condition. However, the end result is often rewarding, with a beer that is well-balanced and satisfying.
To summarize, what makes a beer a lager is its bottom-fermentation process using specific yeast strains that settle at the bottom of the fermentation tank. The use of lower temperatures during fermentation and extended lagering periods contribute to the clean and crisp flavor profile commonly associated with lagers. Whether it's a light and refreshing pilsner or a rich and malty bock, lagers offer a diverse range of styles that cater to different taste preferences.