How to Make It
Place beans in a large bowl or container; cover with cold water to 4 inches above beans. Let stand at room temperature overnight; drain.
Bring drained beans and 10 cups water to a boil in a large Dutch oven, skimming surface occasionally. Add oil, 1 teaspoon salt, thyme, bay leaves, and onion to pan. Reduce heat to low; cover, and simmer 30 minutes, stirring occasionally.
Stir in 1 teaspoon salt. Cover, and simmer another hour or more depending on the bean (see chart, below).
Remove thyme, bay leaves, and onion; discard. Stir in remaining 1 teaspoon salt. Cool to room temperature in cooking liquid. Place beans and cooking liquid in an airtight container; refrigerate.
How Long to Simmer Each Bean Variety
Cook the beans with the aromatics and 1 teaspoon salt for the first 30 minutes. Add the second teaspoon of salt, and cook for the suggested time or until beans are tender. Red kidney beans: 1 hr. Great Northern beans: 1 hr. 15 min. Black beans: 1 hr. 15 min. Cannellini beans: 1 hr. 45 min. Pinto beans: 1 hr. 45 min.