Cut the spareribs into 2-inch individual pieces, ensuring even sizing for consistent cooking throughout the slow cooker. While prepping the ribs, combine the brown sugar, apple cider vinegar, soy sauce, ketchup, and pineapple juice in a bowl, whisking until the sugar dissolves completely. This creates a smooth, well-integrated sauce base rather than having granular sugar settle at the bottom.

Place the ribs in your slow cooker and add the minced garlic and grated ginger directly to the pot, spreading them evenly over the meat. I like to add the aromatics to the ribs before the sauce so they infuse into the meat rather than floating on top. Pour the sauce mixture from Step 1 over the ribs and ginger, stirring gently to distribute everything evenly.

Cover the slow cooker and cook on low for 8-10 hours or on high for 4-5 hours, depending on your schedule. The ribs are done when the meat is fall-apart tender and easily pulls away from the bone. For the most tender results, I prefer the low-and-slow method as it allows the flavors to develop more deeply and the connective tissue to break down completely.

Once the ribs are tender, skim any excess fat from the surface of the sauce if desired. Mix the cornstarch with 2 tablespoons of cold water to create a slurry, then stir it into the slow cooker. Cook uncovered on high for 10-15 minutes, stirring occasionally, until the sauce thickens to a glossy, syrupy consistency that coats the ribs.