Add ground beef and the rest of the ingredients (except sandwich buns) to <g class="gr_ gr_255 gr-alert gr_gramm gr_run_anim Grammar multiReplace" id="255" data-gr-id="255">a 6-quart slow cooker and mix well.
Cover and cook on low for 6-8 hours, stirring occasionally.
If the sloppy joe mixture has too much liquid, turn the slow cooker to high, and cook uncovered for another 30-45 minutes.
Thaw freezer bag in the refrigerator overnight. Reheat the meat mixture in a large skillet on the stove (medium heat for 15-20 minutes) or in a 6-quart slow cooker (high for 1-2 hours) until warmed through.