Explosive Concoction not working with bow?

Explosive Concoction currently cannot be used while wielding a bow. So what kind of weapon should I use, considering that all Spirit skills seem to require a weapon? Please help clarify this for me — I’m looking forward to your response. Thank you!

All concoctions skills require you to be unarmed as of 0.2.
It works similiar to POE 1 and you have no weapon in slot 1 and a shield/focus in offhand no quiver.