You may also know the Imperial IPA as a 'double IPA' (or DIPA). This beer is stronger, because the alcohol percentage is often above 7.5%. The Imperial IPA also contains even more hops than the American IPA. A double IPA is known for its authentic hoppy taste. More and more stronger DIPAs are being brewed and launched. Some of these even go towards 15% alcohol. These ones are called Triple IPAs or Quadruple IPA's. Real hop bombs!!