Is there any danger to letting food cook in a slow cooker for a very long time?
I've recently started using a slow cooker and I was thinking about recipes that could be cooked for days. My main concern is if there are any side effects for leaving food cooking for days that would make this plan unfeasible (dangerous to try). Since it is at cooking temperature, there wouldn't be any reason to worry about bacteria growing on the food. Liquid would be lost over time, which could result in burning if left unchecked, but if I add more every morning/night as needed, that too wouldn't be a problem. All I can see is that most recipes wouldn't end up tasting as well, but undesirable isn't equal to dangerous.
There just seems to be something absurd with the notion of leaving food cooking for 5 days or even 2 weeks without there being any dangers, but I'm having a hard time figuring out what they would be.
You've answered the food safety question yourself. So why would you want to leave anything cooking in a slow cooker for five days or two weeks? It is kind of absurd.
Who would want to eat a century egg or fish that hasn't been thoroughly cooked? What about fried tongue or 'milk' from almonds/soy? What you or I call absurd another may call dinner. Beans that turn to mush? Perhaps that is a new food or part of a new dish? Perhaps something too woody to eat right if cooked regularly will soften and become edible when cooked this long? I'm not saying it will end up with something worth eating, I was just wondering if it could safely be eaten.
@Lawtonfogle Century eggs aren't made like this. Eggs or fish cooked for hours (let alone days) will be overcooked. If you're going to cook something this long there's not much point frying it, and if you're just trying to soften it up before frying, it doesn't take days. And if you want mush, you can generally get it with a few hours of cooking (at most half a day) and a little mashing. I'm not saying it's useless, but the real uses for cooking this long are fairly limited.
A note of warning about newer slow cookers with digital controls -- some of them will automatically shut off after a period of time (less than a day). If you're thinking of doing this, you want to use a slow cooker with a manual switch so you don't run the risk of it shutting off on you.
Perpetual Bone Broth is an example of when this is used. In that case the Slow cooker never gets turned off. When you take some broth out, add some water to top it up. At least once a week remove the bones, filter the stock. The idea is to leach out all the goodness from the bones, which can take several ldays. I do remove the vegies after a couple of hours. No point in overcooking them, and add and remove bones. After a week, remove the bones, filter the stock, and use this as the starter base for your next batch.
It's safe. All that matters for safety is that the food stays out of the danger zone (above 140F).
But it sounds like a pretty reliable way to overcook things. Perhaps that's why it sounds absurd to you? Slow cookers tend to be somewhere between simmer and light boil (probably at least 180F), and there's very little that won't be fully cooked after half a day at those temperatures. If you cook for days, you'll start turning beans and vegetables to mush, and may manage to make meat tough from overcooking. So at best it's pointless, and at worst it's going to mess up your food.