One of the most overused terms in the beer drinking dictionary is 'IPA', and now it seems to be spawning even more bizarre offshoots as anyone who has read the previous post may have realised.
Although 'pale ale' has been around in England since the 17th century, the term 'India Pale Ale' was not coined until 1835, and basically described a beer that had been well hopped. The strength was not really a factor, and it is possible that the stories about strong pale ales being brewed to survive the trip to India may just be a myth. It was the hopping, and the greater fermentation of the wort, thereby leaving less residual sugars that preserved the beer, not the strength. It was a beer suited to the tastes of India at the time, hence its name.
The 'Bow Brewery' was one of the first to export beer to the sub continent, benefitting from the brewers connections with the East India Company. Gradually, other brewers became involved and several from Burton also exported their beer to India as other markets declined throughout the 19th century. Other North American breweries were also brewing their takes on the beer style before the end of the century, again using the term 'IPA'.
But what of the 21st century? As I have pointed out earlier, there is nothing in the history to say an IPA has to be strong, so there is no problem with the 3.6% Greene King IPA being referred to as such. Any light hoppy beer can theoretically be classed as an IPA, and plenty are. The suggestion that IPA's should be strong seems to be a product of the American market of the 1930's. These were known in England at the time as 'Double' or 'Imperial' IPA's, but that gradually went into decline through the 20th century and have only recently made a comeback.
So there we have it. At the moment we can find half IPA's, double IPA's, American IPA's, or Imperial IPA'S, and even Belgian IPA's. All they have to do is vaguely fit the original brewing style of the early recipes. I am not so sure about Black IPA though, surely a black pale ale is a contradiction in terms. Unless you know better.