Stockpot method. Put beans in a pot with enough water to cover by 21⁄2 in. Cover, bring to a boil over high heat, and boil 3 minutes. Reduce heat and simmer until beans are tender, about 11⁄2 hours, adding salt, if you like, after 1 hour.
Instant Pot method. Put beans in pot with water to cover by 1 in. and 1⁄2 tsp. salt, if you like. Secure lid and set pressure to Sealing. Select the Multigrain setting (it adds a presoak) on high and set cooking time for 35 minutes. Let pressure release naturally for 15 minutes. Switch to Venting and let remaining steam escape.