I have encountered this advice about flatulence avoidance in a number of places. Kim Williams's is a simple and prosaic description of how to treat the cooking of beans. It is culled from the introduction to the recipe for "Savory Four-Bean Salad" found in her Cookbook & Commentary: A Seasonal Celebration of Good Food for Mind & Body.

With either method I drain off that soaking water, add fresh water, cook, covered, for one half hour, then drain again. Then I add fresh water and cook the beans until they are tender. This is the final cooking and the liquid stays with the beans.

Me, I discard the soaking liquid. Cook. Then discard the cooking liquid. And store with fresh water unless I am adding them immediately to a dish. Whatever the sequence of rinsing, a colander is a useful tool for cooking beans.

And so for day 421