To cook rice porridge in an electric slow cooker, the general guideline is to set the slow cooker to the "porridge" or "stew" setting and allow it to cook for approximately 4 to 6 hours on low heat. This duration ensures that the rice is fully cooked and the porridge achieves a creamy, soft texture. The exact cooking time can vary depending on the specific slow cooker model, the rice-to-water ratio, and the desired consistency of the porridge.

The reason for this extended cooking time lies in the nature of the slow cooker, which utilizes low and steady heat to gently cook ingredients over an extended period. This method is ideal for rice porridge because it allows the rice grains to absorb the water and break down, creating a smooth and creamy texture. The slow cooking process also helps to meld the flavors of the rice and any additional ingredients, such as milk, sugar, or spices, resulting in a rich and comforting dish.

According to the National Center for Home Food Preservation, slow cookers are particularly well-suited for cooking rice because they prevent the rice from burning and ensure even cooking throughout. The data from the center suggests that slow cookers can maintain a consistent temperature of around 200°F (93°C), which is perfect for the slow cooking of rice porridge. Additionally, the extended cooking time allows for the natural thickening of the porridge as the starches in the rice grains release into the water.

In conclusion, cooking rice porridge in an electric slow cooker typically takes 4 to 6 hours on low heat. This method ensures a creamy texture and rich flavors, thanks to the slow cooker's ability to maintain a consistent temperature and the extended cooking time that allows for the rice grains to fully cook and the flavors to meld together.