Dark Crystal 400 has a high degree of caramelisation with dried fruit notes, the sweetness of other Crystal Malts are replaced by bitter coffee flavours.
Dark Crystal Malt has the highest degree of caramelisation. The flavours are now transformed into sultanas, raisins, plums and dark, dried fruits. By now the sugars are actually being broken down by chemical processes and so the residual sweetness that the other Crystal Malts impart are being replaced by an increased in bitterness flavours.
Crystal Malt sugars are non-fermentable, so add a level of dextrin sugars that are preserved trough to the final beer.