Look for any large dirt particles or stones in the dry navy beans. After cleaning them, rinse them with clean water and drain the water.
Take a large pot and add water and baking soda to it. Mix them and then add washed navy beans to the pot. Boil all of them together for once on a high flame. Then remove the pot from the flame, cover it with the lid, and place it aside overnight.
After beans have been soaked overnight, preheat the oven to 300 degrees Fahrenheit.
Take the pot with soaked beans, drain the water, and add other ingredients: onion, salt, and brown sugar. Give them a good mix.
Then add the cooked and diced bacon to this mixture and combine well.
Take a casserole dish or a Dutch oven with a lid. Transfer the bacon and beans mixture to it. Bake at 300 degrees Fahrenheit for 5 hours.
Stir the mixture after every hour and add in some water if necessary so that the beans do not dry out and are cooked soft properly.
When 5 hours have passed, check if the beans have been cooked properly. Also, check the consistency of the mixture which should be thick. Then check for the seasonings. Adjust if needed.
Homemade Grandma Brown's Baked Beans are ready. Bon Appetit!