The millet should be washed before cooking to minimize or eliminate the bitter taste - it is said. Honestly, I've never washed it and it has never tasted bitter. But maybe that is different from millet variety to millet variety. If you prefer to wash your millet as a precaution, make sure that you use a very fine-mesh sieve *) so that there is still millet left after washing. Alternatively, you could put the millet in a tall container, fill with water, stir and drain off the water.