Blake Lenoir wrote: ... Any way to keep the beans spoiling in water and keeping them fresh for the next cooking day?
Pretty much all dried beans contain a toxin with the barely pronounceable name: Phytohaemagglutinin.
Different beans contain more or less of it (example, "white kidney beans" has 1/3 the amount of "red kidney beans" which has the highest concentration.)
Under-cooked beans actually have more of it bioavailable than fully cooked beans.
Soaking overnight then discarding the soak water is one way reduce the concentration. It shouldn't make the beans go bad in any way.
The beans *must* be boiled to deactivate the chemical, so the link below doesn't recommend slow cooking (although if the beans are already cooked, slow cooking as part of a recipe won't undo the boiling benefits).
https://www.cfs.gov.hk/english/multimedia/multimedia_pub/
I soak mine overnight in a jar, drain them, and then pressure cook them. Pressure cooking is quick and saves energy, but it does require paying attention to the cooker. I discard the pressure cooking water also. Phytohaemagglutinin prevents the absorption of nutrients I need in my diet, so to me, it's safer to discard the cooking water.