20 Everyday Ingredients That You Probably Shouldn’t Be Putting In Your Slow Cooker

No kitchen is truly complete without a slow cooker. A simple appliance, all you need to do is turn the thing on, toss some ingredients inside, and let them cook over time. And that’s it! There’s just one problem. Slow cookers aren’t suitable for every meal – and they can sometimes be downright dangerous. So here’s a look at some foods you shouldn’t prepare with the gizmo.

20. Tomatoes

It’s an age-old dispute – is a tomato a fruit or a vegetable? Well, the answer depends on your perspective. If you’re a scientist you’d classify it as a fruit, but if you’re a chef you might think of it as a vegetable. But whatever the case may be, you can likely agree that it’s often an essential component of a given meal.

There are countless way to prepare a tomato, but you should be wary of tossing it inside a slow cooker. You see, a tomato contains a lot of acid, and this can actually react negatively with the appliance. Some slow cookers – particularly older models – can contaminate food with lead, and the acid in tomatoes only makes things worse.

19. Vinegar

Researchers have found that slow cookers dating back to the 1970s are particularly troublesome with regard to the amounts of lead they give off. You see, lead is a toxic metal that can harm any given organ of the human body. Overexposure to the metal, in fact, can even bring about death.

According to the British health service known as the NHS, “Lead poisoning can affect almost all parts of the body, including the central nervous system, kidneys, and reproductive organs.” With this in mind, then, it might be best to steer clear of adding vinegar to an old slow cooker. The acid it contains might just encourage the lead to spread.


18. Spinach

Said to have first emerged in Persia, spinach is an extremely healthy foodstuff that many of us enjoy today. According to experts, the leafy vegetable has properties which help to bring down our blood pressure. It also helps with our eyes and it’s good for the body’s ability to avoid cancer.

Now, spinach can be consumed raw, but many people opt to cook it in some way. If you opt to heat the vegetable up, however, be sure not to overdo it. If spinach is cooked for too long, it’ll turn to mush. With that in mind, slow-cooking the green is probably not the way to go. You don’t want to risk losing all those nutrients.


17. Couscous

Having emerged from the northern regions of Africa, couscous is now enjoyed by people all over the world. And why wouldn’t it be? It’s easy and quick to prepare, and you can pair it with all sorts of dishes. Having said that, problems do arise when you try to slow-cook it.

If you add couscous and some liquid to a slow cooker, you should prepare for your dish to end up a disaster. The couscous, you see, will soak up too much of the broth and end up becoming all mushy. The best thing to do, then, would be to prepare it separately to the rest of the meal.


16. Rice

Packed with essential nutrients, rice is a vital source of energy to most people on Earth. Indeed, it’s said that over 50 percent of the planet’s human beings rely on the grain, most of whom reside in Asia. Having said that, it’s becoming increasingly vital to Latin American and African populations, too.

Now, it’s important to prepare rice correctly. While it might be tempting to just throw your rice into a pool of water and prepare it with the slow cooker, this would be a mistake. If rice is left to cook over too lengthy a period, it’ll end up becoming gluey. Instead, parboil the rice and then add it to the slow cooker for only a short duration.


15. Dairy

Milk, as many of us know from firsthand experience, often curdles once it’s been exposed to high temperatures. Essentially, this just means that the proteins found inside dairy end up being clumped together. In reality, this means that the milk product will contain more lumps than anyone would ever wish for.

However, for those of us who want to make our own homemade yogurt, curdling milk is an essential step. So, if your slow-cook recipe requires some dairy products, make sure you only put them in the cooker towards the end of the process.


14. Bacon

Bacon is a surprisingly versatile foodstuff. Although we might associate it with breakfast – there’s little else better, after all, than bacon and eggs in the morning – there are plenty of other ways to consume it. For instance, we can eat it as part of a sandwich or as a component of salads or even soups.

The thing about bacon, though, is that many of us like it best when it’s nice and crispy. But this is a state which is hard to achieve when preparing it in your slow cooker. Ultimately, a slow-cook will lead the meat to emerge in a soft and limp condition – the opposite of what you’d prefer.


13. Fresh herbs

It’s not overstating things to suggest that fresh herbs are the stuff of magic. By adding the perfect amount during the cooking process, these flavorsome leaves can ultimately turn a meal into something great. And on top of that, they actually contain plenty of nutrients which are beneficial to our health, too.

However, to get the best out of fresh herbs, it’s best not to prepare them inside a slow cooker. You see, many of them will become rather flavorless if they’re left to stew in heat for longer than necessary. Plus, they might even fade from a lovely green into an unappealing shade of brown. Best to add them to the dish at the end, then.


12. Dried beans

Beans are great, of course, but you need to be really careful when you’re preparing them for consumption. You see, multiple varieties of dried-out beans – kidney beans, in particular – are actually toxic. So, if you need them for a dish, what can you do to make them safe to eat?

First things first, you’ll need to blast the beans with lots of heat. This will impair their toxic elements so that they’re safe to eat. But preparing them in a slow cooker might not do the trick, as such appliances are too gentle. So, before you add them, you should boil them for roughly ten minutes beforehand.


11. Boneless chicken

Depending on whatever mood you’re in, boneless chicken breasts are always handy to have chilling in the fridge. So many different recipes can be achieved with the help of the white meat, after all. But be warned, some ways of preparing chicken breasts are better than others.

Indeed, if you decide to slow-cook boneless chicken, you undoubtedly run the risk of ruining an otherwise delicious meal. Chicken breast, after all, has a rather sinewy texture as it doesn’t contain all that much fat. This means it won’t cook as well as different kinds of meat and can dry out.


10. Eggs

Eggs are an incredibly versatile foodstuff that can be prepared in a huge variety of different ways. They’re cheap, simple and absolutely packed to the brim with vital protein. All in all, then, they’re a perfect choice for any meal, but many of us, of course, prefer them for breakfast.

However, one method should be avoided at all costs. That is, you should refrain from ever using your slow cooker to prepare them. After all, eggs tend to cook swiftly, so leaving them to slowly heat up for hours at a time is clearly going to end badly.


9. Chillies

Chillies are a diverse bunch, with no less than 200 types known about today. Many of these are red, but they can also be green, orange, yellow and even black. They come in different sizes, and their spiciness varies greatly. As a general rule of thumb, however, we might say that the smaller varieties tend to be the most fiery.

Although chili peppers can really give a dish a delicious kick, caution should be exercised. And especially so if you’re using a slow cooker to prepare your meal. Spicy ingredients tend to become even more flavorsome as they’re heated up. With that in mind, it might be best to add chili pepper to your dinner right at the end of the cooking process. Otherwise, the chili might just overpower everything else in the cooker.


8. Fillet steak

When cooked correctly, a fillet steak can blow all other cuts out of the water. You see, even though they can be less flavorsome when compared against certain other types of cut, they do tend to be the most tender. However, that counts for nothing if the strip is prepared in an unsuitable manner.

Bearing this in mind, then, you really shouldn’t throw fillet steak into your slow cooker. You see, a fillet cut is quite thin, meaning it could end up with a tough, leathery texture. The best meat cuts to prepare on a slow cooker tend to be much thicker.


7. Frozen meat

Throwing meat into the freezer can be an extremely worthwhile thing to do. It means, after all, that your home is never short of food. However, you really do have to be careful about how you make use of this frozen fare. Handling it in an inappropriate manner could prove disastrous.

You see, if you put frozen meat directly into the slow cooker, then you run the risk of ruining your meal. That’s because slow cookers operate at a relatively low temperature. If you add unthawed matter into the mix, then you’ll end up cooling things down even further. And this will make the whole meal take longer to cook.


6. Seafood

For many people, no week is complete without a little seafood. And considering that it’s a meal without too many calories that’s packed full of essential minerals and vitamins, why wouldn’t you want to indulge? Of course, it’s vital that seafood be prepared correctly.

Fish, for instance, doesn’t take long to finish cooking. If you leave it on the heat for too great a time, in fact, you might give it a texture like rubber. Similarly, scallops can be ruined with too much cooking time. As such, seafood should generally be prepared away from the slow cooker.


5. Broccoli

The health benefits of broccoli have been drilled into many of us since the early stages of our childhood. And given that the tree-like vegetables are packed with essential minerals, fiber and vitamins, we’d do well to remember it in adulthood, too. But to get the best out of broccoli, we should make sure we prepare it correctly.

If broccoli is overcooked – as happens when it’s prepared in a slow cooker – then it turns to mush. That equates to an unpleasant meal, but it also means that the broccoli won’t possess the same amount of healthy benefits as it should. Yes, if the vegetable is heated up for too long, many of its nutrients are destroyed.


4. Peas

Many people enjoy peas, as they’re delicious and healthy. In fact, some research even suggests they can aid the human body in guarding itself against terrible conditions like cancer and heart disease. But if you want to get the best of the greens, make sure you cook them right.

You see, while certain vegetables can cook beautifully inside a slow cooker, others most certainly do not. Root veg, for instance, works really well, but more fragile and starchy greens like peas can just turn to mush. So, it’d definitely be best to look for a better method of preparation.


3. Lemon juice

The zesty bite of lemon juice can really turn a good meal into a great one. Whether it’s a sweet or savory dish, the citrusy notes of lemon can be a perfect addition. Having said that, you do have to be careful if you’re adding it to an old slow cooker. In fact, you might be safer to avoid it altogether.

If your slow cooker is old, it might give off high levels of lead. Lemon juice, then, can actually make this worse. And as Britain’s NHS has explained, “[Lead] commonly causes weakness and abdominal discomfort and less often causes abdominal pain, vomiting, constipation, foot and wrist drop and anaemia.” Better, then, to play it safe.


2. Pasta

It’s such a simple foodstuff and is loved by so many people. Flour-based pasta is a staple of Italian cuisine, but it’s adored by food lovers all over the world. And moreover, it’s easy to prepare, often taking only minutes. Of course, it doesn’t take too much to ruin it, either.

You see, the shape of pasta is an essential part of its character. And if you throw it into a slow cooker, it may go soft and mushy. As writer and slow cooker aficionado Stephanie O’Dea explained to Reader’s Digest, “If you don’t follow a recipe for pasta that is written specifically for a slow cooker and take note of the timing, it loses shape and becomes wallpaper paste.”


1. Alcohol

Similar to the manner with which salt helps to draw flavor out of ingredients, alcohol can also enhance a dish. Whether using liquor, beer or wine, alcohol can really bring out the best of certain recipes. But it needs to be cooked correctly, of course. Otherwise, your meal could be ruined.

If you heat alcoholic beverages at high temperatures, the alcohol itself will burn away. If the heat is too low, however, then this won’t happen. The alcohol will remain in the dish and the meal will be left with an unpleasant taste. Bearing that in mind, you really shouldn’t use alcohol on your slow cooker.