How do I keep black beans black?

[skllwmn]

Every time I cook black beans they lose the nice black color you see in commercially or restaurant prepared black beans. Mine always end up sort-of grey.

What's the secret to keeping them black?

[todao]

Try a pinch of baking soda ....

[escondido123]

Mine always stay black, but maybe if you over cook them the outside black skin falls off?