Spread the beans on a tray and pick out any small stones or shriveled beans. Rinse them in a colander.
Soak: put the beans in a large bowl and cover with cold water by at least 3 inches. Leave for 8–12 hours or overnight. (Quick soak: cover with water in a pot, bring to a boil for 2 minutes, then turn off the heat and cover for 1 hour.)
Drain and rinse the soaked beans. Put them in a large pot with the onion, garlic and bay leaf, and cover with fresh water by 2 inches.
Bring to a boil over high heat, skim off any foam, then lower the heat to a gentle simmer. Partially cover the pot.
Simmer, stirring occasionally and adding hot water if the level drops below the beans. After 30 minutes, add the salt.
Start tasting at 45 minutes. Most soaked beans take 45–90 minutes (chickpeas can take up to 2 hours). They are done when several beans are creamy all the way through with no chalky center.
Remove the aromatics. Let the beans cool in their cooking liquid before storing them.