Using the term “black cumin” can be tricky, as there are a couple different spices that go by that name. Most notably, nigella seeds are frequently referred to (wrongly) as black cumin. True black cumin, known as kala jeera (literally “black cumin”) in Hindi and sometimes called “imperial cumin,” is much more uncommon and hard to find. These little seeds look like standard cumin, except that they are longer, skinnier and darker.
The flavour of black cumin is mellower, more piney, and a little sweeter than regular cumin. It is primarily used toasted and whole in curries of northern India and Middle Eastern stews and breads.