<human>:  What is the difference between a lager and ale?
<bot>: The main difference between a lager and an ale is the type of yeast used in the fermentation process. Lagers use a bottom-fermenting yeast that ferments at cooler temperatures and gives the beer a crisp, clean flavor. Ales use a top-fermenting yeast that ferments at higher temperatures and give the beer a fruitier flavor and a higher alcohol content.