In the big world of beer, there are ales and there are lagers. What makes ales and lagers different and are ales and lagers really different? Yeast. And yes. Because the two types of yeasts used in beer making are quite different from each other, the fermentation (the breakdown of a substance by yeast) can take place at different temperatures, which means the attenuation, the process of covering sugars into alcohol and CO2 (and in beer lingo, just how much of this has occurred), can be a slow, long process or a fast and quick process (creating a not well attenuated or a well attenuated beer respectively), which in turn affects what fruity esters and compounds are left in the beer, the clarity of the beer, and how much carbonation is in the beer.
So, ales are generally fermented quick and warm, which leaves them packed with esters, which gives us the fruity, bold flavors, and are robust, hearty, rich, and complex
Since lagers are fermented cold over a long period of time, they are often very clear and crisp beers with a smooth finish. They often lack the bold or fruity flavors that accompany ales.
To understand the differences in beers, you have to look past the differences between ales and lagers. You’ve got to look at the varieties of beer that exist. Here are 72 styles of beer that branch from the Ales and Lagers family.