An ale is a beer that is produced with a top fermenting yeast strain. In general, ales are fermented at warmer temperatures (60 - 70ºF) and for a shorter period of time (2-3 weeks) than lagers.
Most top fermenting yeast strains produce phenols, which impart spicy undertones to a beer, and esters, which provide fruity characteristics. Like lagers, ales can range dramatically in color from straw-gold to black, and can be found with a huge variance in strength, from 0.5% ABV to more than 12% ABV.