You overcrowd your slow cooker
This is especially important if you’re cooking meat. Meat needs room to cook, so be sure once you fill up your slow cooker that the lid still fits snugly on top. A good rule of thumb is to fill your slow cooker up halfway to two-thirds of the way, according to the National Pork Board. Check out these slow-cooker recipes for Sunday dinners.
You lift the lid to stir too often
It’s tempting, I know, but it’s best to just let the Crock-Pot do its job and cook your food. According to Christopher M. Wilmoth, corporate chef at Lee Kum Kee, lifting the lid too often to stir will let out heat and prolong the cooking process. Your slow cooker is called that for a reason, so resist the urge to peek under the lid and just let your slow cooker slow cook.