There are many variations in the beer industry. For example, Pale Ales are beers known to be more bitter, hoppy and crisp. Pale Ales are brewed more lightly roasted pale malts. Sierra Nevada Pale Ale is one example of these beers.
English Indian Pale Ales and American India Pale Ales are IPA beers. They were originally brewed as an extra-hopped beer for the long sea voyages from England to India, taking advantage of the special preservative properties of hops to keep the beer fresh. These IPAs are tended toward earthy, woodsy, and spicy flavors. American IPAs have added to the English IPA its own interpretation. American IPAs are more hopped; typically flavors feature resinous pine and bitter grapefruit flavors.
http://www.thekitchn.com/whats-the-difference-pale-ales-142695
Beers Blog 