Black Bean Dye bath ( Natural dyes) in Tales from the Spinning Siren

I have NOT done this one. This is from a friend who dyes with natural dye and i want to try it as soon as i get black beans!

Small bag of dried beans.
Put them in a large glass jar, Fill with hot water with two extra fingers of water over the beans. Allow to sit overnight. ( I think ill seep during the day when its hot)
Strain beans out ( toss them? Eat them? I donno lol they would be soft! )
Add pre mordanted wool to the stained water and soak overnight ( or in the heat you know, hot hot hot here)
Can get shades of grey to blue!!

Mordant wool-
Add water and 10% Alum in a dye bath, Simmer to mix well. Allow to cool and soak skeins or wool in the mixture. (Called a mordant)