The creation of India Pale Ale (IPA) during the 1790s was the result of tremendous efforts by British brewers to overcome a difficult problem.
During the 1700s beer did not keep well on long ocean voyages, especially into hot climates. These hot environments resulted in the arrival of flat, sour beer. The high hopping and alcohol of IPAs solved this problem. American versions of this style tend to be bolder, stronger, and hoppier.
Colour is from golden amber to light copper, usually with an orange tint. Malts are used to balance the hops and may have a mild sweet flavor in American varieties. In English versions, malts may have a biscuity or toasty flavor. ABV ranges from 5-7.6% and IBUs from 40-60+.
Summary from www.beertutor.com