Dried cannellini beans cook up perfectly tender thanks to a salty soak.
Day 1: Add 4 cups water and 2¼ teaspoons salt to large bowl. Use wooden spoon to stir to dissolve salt.
Place colander in sink. Add dried beans to colander. Search through beans and pick out any small stones or broken beans and discard. Rinse beans with cold water.
Add drained beans to salt water in bowl. Cover bowl with plastic wrap and let beans soak at room temperature for at least 8 hours or up to 24 hours.
In large saucepan, combine drained beans, remaining 1½ teaspoons salt, and remaining 5 cups water. (Return colander to sink for step 8.) Bring to boil over medium-high heat.
Reduce heat to medium-low and cook at gentle simmer (small bubbles should break occasionally across surface of water), stirring occasionally with wooden spoon, until beans are barely al dente (tender but still chewy in the middle), 25 to 30 minutes.
In 12-inch nonstick skillet, combine oil and garlic. Cook over medium heat until garlic begins to brown lightly at edges, 3 to 4 minutes.
Add red pepper flakes and cook for 30 seconds. Add drained cooked beans and stir gently to coat with oil. Cook, stirring occasionally, until heated through, about 2 minutes. Turn off heat. Sprinkle with parsley (if using) and serve.
Dried beans start out as the seeds of a bean plant that grow inside long pods (see the Bean There, Done That activity). Those seed pods are dried in the sun until the water inside the beans evaporates, making the beans dry and hard. Drying beans this way allows them to last a long time on your pantry shelf.
To turn them tender again, dried beans need to be cooked in liquid, or rehydrated, which can take hours and hours. One way to speed things up? Brine the beans. Soaking dried beans in a saltwater solution does two things: It softens the beans’ skins (the seed coats) and it shortens the time it takes to cook them. The skins of beans contain pectin, a molecule that “glues” plant cells together. As the beans soak in the brine, sodium ions in the dissolved salt weaken the pectin in the beans’ skins, making them softer and able to expand (instead of explode) as the beans absorb water. During their time in the brine, the beans start to absorb water, first through their hilia (the little holes on the curved parts of the beans) and eventually through their entire seed coats. This gives the beans a hydrating “jump start” and means you won’t have to cook them for quite as long.