The manufacturer sets Crock-Pot temperatures for safe cooking with the low setting at approximately 200 degrees Fahrenheit and the high setting at 300 degrees Fahrenheit. Slow cooker owners should not attempt to vary the preset temperatures.
When cooking with a slow cooker, it is essential to ensure the food reaches above 140 degrees Fahrenheit as quickly as possible to kill any bacteria. If possible, it is best to start all slow cooker meals on high for the first hour, and then reduce the heat to low for slower meal preparation. Thawing meats before cooking ensures they reach the safe temperature more quickly. Cutting large pieces of meat into smaller chunks helps to ensure that the inside of the cut reaches the safety zone without any problems. At the preset temperature settings, most meals cook safely and are ready after four to five hours on high or eight to 10 hours on low.
If preparing foods for the slow cooker the night before, storing them in separate containers in the refrigerator is the best practice. Storing foods in the unit overnight provides too much time for bacteria to grow.
Removing the lid of a slow cooker allows steam to escape and reduces the cooking temperature. The decrease in temperature increases the cooking time. Most manufacturers recommend opening the lid only once to stir or add ingredients a couple of hours before serving.