I thought raisins were from dried black or red grapes and sultanas from dried green ones? Sultanas are the ones that plump up nicely when soaked in rum or whisky :-)
Hoppy....generally, they are a different grape variety, from what we call here in Britain as raisins.
Another often confused variety are what we call "currants" I always thought, until a couple of years ago that they were dried blackcurrants. But they are just another variety of dried grape ::
Raisins are for the more staid in society where sultanas are known to be preferred by those of a more outgoing, hedonistic bent as celebrated in the ditty Sultanas Of Schwing.