Add all ingredients to 6-quart slow cooker and stir to combine. Cook on high for 6 to 8 hours or until beans are soft and mash easily. Add more water if necessary during cooking to keep beans fully submerged in liquid.
Reserving the liquid, strain the beans out into a large bowl (see note). Mash with a potato masher or immersion blender. Add the reserved liquid until you reach the consistency you desire.
Serve, or cool completely and freeze in portions appropriate for your family.
Video
Notes
Makes 12 cups or 24 (½ cup) servings.
These taste significantly less salty than the canned version. Make sure to check for seasonings and add salt as desired.
Reserve some of the beans before mashing if you would like to use them whole for other recipes.
Refried beans will keep in the refrigerator for three to four days. Freeze them in serving size freezer containers for up to 6 months. Spray the containers with nonstick spray before filling them and the beans will pop right out.