Can You Overfill Or Underfill A Slow Cooker?

So you’ve just got your hands on a slow cooker and want to learn about how to make delicious slow-cooked meals. I’ve made the common mistake of putting the wrong amount of food and liquids into their slow cookers before. Can you overfill a slow cooker?

You can overfill a slow cooker if you fill it beyond about two-thirds of its capacity. While it simmers, the liquid can bubble up and spill out of the side to cause a mess. It needs a gap at the top to work most efficiently. It will also take longer to cook if the slow cooker is too full.

Because you can easily batch-cook meals in the slow-cooker, you may be tempted to cook as much food as possible and fill your slow-cooker to the brim with vegetables, meat, and broth. But due to the process of slow cooking, you’re going to be spilling food and making a mess if you fill the pot to the brim. Here are some tips for cooking efficiently.

What Happens If You Overfill A Slow Cooker?

The fill level for slow cookers, also known as crockpots, will vary from recipe to recipe. If not mentioned, anywhere between half to two-thirds full is a good rule of thumb to go by. Sometimes you need to adjust the fill level through trial and error.

When a slow cooker is filled too near the top edge during the simmering stage of the slow cooking process, the pot can overflow and spill due to a vacuum created by the slow cooker’s lid. Leaving room for the food and liquid is imperative for the slow-cooking process.

When a slow cooker is overfilled, food doesn’t cook as evenly and thoroughly as it should. And, if you keep the fill level at about two-thirds, you can avoid any mishaps. You can make sure that your food is ready on time and you don’t have to be inconvenienced by constantly checking up on it.

Slow cooking creates a lot of steam, which condensates on the lid and drips right back down into the pot. In traditional cooking, this would evaporate and reduce the sauce, but very little liquid is lost in slow cooking due to the lid.

In short, overfilling your slow cooker will be messy and inefficient. You should adopt a mantra of less is more when it comes to how much you should fill your slow cooker. That might mean you need a bigger slow cooker if you are feeding lots of people!

Can You Underfill A Slow Cooker?

You can underfill a slow cooker if the cooker gets dry at the bottom from lack of liquid. This causes the bottom heating element to start burning the food. It is best to sit all food in enough liquid to allow it to simmer without any problems.

The lid of a slow cooker ensures little liquid is lost in the lengthy cooking process. A bit of liquid will escape and some will evaporate and condense on the lid. The majority of the liquid will remain and make the sauce. Ensure you add enough that you don’t need to keep opening the lid and cooling the pot, which lengthens the cooking time.

For stews and casseroles, underfilling isn’t usually a problem because you are already using a lot of liquid for the sauce.

For things like pulled pork and pot roasts where you are cooking a whole piece of meat, just ensure you have enough liquid to avoid it drying up. That doesn’t mean you have to cover the whole piece of meat with liquid. Usually half full is a common rule, but you can use less if you want a more concentrated sauce. See my post on cooking a roast in the slow cooker.

Does Meat Need To Be Submerged In A Slow Cooker?

Meat doesn’t need to be submerged while slow cooking but does need to have enough liquid to cover the bottom of the pot and stop any sticking or burning. The steam and ambient heat will slow cook the meat.

Braising is the term used to cook meat partially covered in liquid, and this is essentially what happens in a slow cooker when you are not stewing. It doesn’t need to be fully submerged, or even half submerged. Sometimes half a cup of liquid will do.

Most dishes will release liquid when cooking. Fats will render out, and water will be released from veggies. If your meat is on a bed of onions, then those onions will become watery. In most cases, you don’t actually need to add any liquid, but I think it’s good practice just to be safe.

Alternatively, you can submerge the meat halfways up or more. Remember this makes a more watery sauce that won’t thicken as liquid doesn’t evaporate. When the meat is cooked, strain the juices and add a smaller amount back to your dish (like pulled pork). You can reduce the cooking liquid in a pan so that it’s more flavorsome.

Common Slow Cooker Mistakes To Avoid

Overfilling and underfilling are just some of the common mistakes made by anyone new to slow-cooking. Now that you are more familiar with the cooking process, you should also be aware of some of the other mistakes that you may be making.

If you are slow-cooking chicken, be sure to take the skin off first. Chicken skin becomes rubbery and gelatinous if you leave it on in the stewing process. You should sear chicken, and your meat will be far tastier and juicier in its consistency if you remove the skins first.

Chicken bones can disintegrate into the broth during the process, which could be a choking hazard, which means you may want to take it off the bone about halfway through the process. It should slide off quickly, and by the time you’re done cooking, you won’t have to fish anything out of the pot.

Avoid expensive and lean cuts of meat. With expensive cuts, you’re simply wasting your money. Slow cookers are great at tenderizing cheap cuts, which is what makes them so popular. Overcooking expensive steaks make them rubbery. Lean cuts that don’t have any marbling or fat can get chewy when cooked over a long time.

Brown raw meat before slow cooking. You should always start by searing your meat in a pan beforehand, allowing it to be browned, making it taste better, and lock in all of the flavorings from the fat and any spices you’ve added to it. Many recipes cover your meat in a layer of flour before adding it to the slow-cooker to give your stew a thicker consistency.

Avoid adding too much alcohol to your recipe, especially if you’re adjusting a recipe that was not originally intended to be cooked in a slow cooker. Beer and wine in regular stovetop recipes will evaporate quickly and merely leave behind an alcohol aroma. In a slow cooker, it can’t reduce so will be stronger. Opt to reduce the amount of alcohol you add to the recipe to avoid the alcohol imposing itself.

Add fresh herbs and soft vegetables at the end of the cooking. This helps with their delicate texture and flavor. Wait until you’re getting into the final hour of the slow cooking process to add your herbs. They will cook quickly but not so fast that the recipe doesn’t retain its flavor or crunch.

Finally, avoid lifting the lid as much as possible. Your slow cooker needs to be sealed appropriately to do its job. The meat needs to be evenly cooked, and disrupting the process can compromise that.


Using a slow cooker can seem intimidating at first, and overfilling a slow cooker is just one of many mistakes that anyone new to the process can make. Now that you’re aware of the mistakes you need to avoid, you’ll start to get the hang of it and it becomes second nature. Soon enough, you’ll be confident in leaving your meal to cook throughout the day while you’re at work, and you’ll be enjoying a delicious meal when you get back home!

Have any questions? Ask me in the comment section below and I’ll get back to you.

Tom Hambly

Tom Hambly is the founder of Boss The Kitchen. With a background in cooking and building websites, he enjoys running this site to help other cooks improve. About Tom Hambly.

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