Beer happens to be the oldest recorded recipe known to man, and over thousands of years, it has been transformed into so many categories and given so many different labels that they are almost impossible to keep track of. I mean seriously – beer, lager, ale, stout – beer is beer, who cares what it’s called? Hoptometrists do, which is the reason for this first-of-many feature, “What is a Lager?”
Truth is, all beers are essentially either lagers or ales. Everything else is just a specific brewing style of one of these two types of beer. Three main factors distinguish these two forms of beer: yeast, time and temperature with yeast being the most significant difference.
Lager yeasts like lower fermentation temperatures (typically 46 to 55 degrees Fahrenheit). Lager yeasts produce less fruity esters than ale yeasts, but can produce more sulfur compounds during primary fermentation. Many first time lager brewers are astonished by the rotten egg smell coming from their fermentors, sometimes letting it convince them that the batch is infected and causing them to dump it. Don’t do it! Fortunately, these compounds continue to vent during the conditioning (lagering) phase and the chemical precursors of other odious compounds are gradually eaten up by the yeast. A previously rank smelling beer that is properly lagered will be sulfur-free and delicious at bottling time.
The lower fermentation temperature decreases the rate at which the yeast works, and lengthens fermentation times. The primary fermentation phase for ales is often 2 – 5 days, but 1 – 3 weeks is normal for a lager, depending on the malts used, the yeast strain, and the temperature at which conditioning occurs.
Lagers produced worldwide are usually either light or dark, and vary greatly in flavor, color, and composition. However, because lager yeasts ferment more aggressively, they leave behind less residual sweetness. This results in a clean beer with lighter aroma and flavor. They are also typically higher in alcohol content and served at cooler temperatures than their ale counterparts.