this is the most critical step, so take notes! Rinse the beans well and add them to a bowl of water. The beans should be covered by 2 in (5 cm) of water.
Let them soak overnight at room temperature. When the beans are done, they’ll split easily when squeezed. Split one open and look—if the inside is flat and buttercup yellow, it’s ready. If the inside is concave or rubbery, let the beans soak longer. The soaking time can vary. We’re recommending 10 hours, but don’t be worried if it takes up to 18.
Drain the beans through a sieve or strainer, and reserve the soaking water. Add more filtered water to the reserved water until you reach a total of 8 cups (2 L).