Why do Slow Cookers Crack? (Safety Tips Included!)

Slow cookers are wonderful. I’ve used them countless times and occasionally left them on while I was at work or overnight. However, I’ve recently heard concerns about their cracking. I made the decision to look into the cause of slow cooker cracking.

Here is what I discovered:

Slow cookers only break in one of three situations:

  1. Rapid temperature swings
  2. Using it on a stovetop burner
  3. Pressing it down firmly on the counter could cause them to crack

However, there is much more to explore, so let’s continue examining some of the most pertinent questions.

Top Causes of Slow Cookers Cracking

The following are the main causes of slow cooker cracks:

  • Extreme temperature changes, such as placing the ceramic insert directly in the shell to heat up after having it in the refrigerator all night.
  • Using a Crock-Pot to heat a huge, fully frozen object.
  • A hot ceramic insert is submerged in cold water.
  • Direct use of the ceramic insert on a stovetop burner.
  • Making a small crack in the ceramic insert by pressing it down too firmly in the sink or on a counter; the crack will subsequently grow when heated.

But placing a hot slow cooker into cold water increases the likelihood of cracking.

For instance, it can be tempting to simply place the insert into the sink and fill it with water to soak after we’ve served the food from the Crock-Pot.

If the water was cold enough, doing that while the ceramic insert is still hot could probably cause your slow cooker to fracture.

Setting the ceramic insert down on a hard surface with too much force could also cause cracks. In some cases, those cracks might be microscopic but the next time the slow cooker is heated, it could cause the cracks to break apart.

Always fill your slow cooker at least one-third of the way full, according to Crock-Pot themselves.

Additionally, without any liquid in your slow cooker, you run the risk of burning or scorching your food. And, unless the item already has significant moisture or fat, the food will dry out.

But there’s also a tiny chance of cracking if used for too long at once.

Last but not least, make sure your slow cooker’s ceramic insert reaches room temperature before reheating any leftovers that were in the refrigerator.

Can You Fix a Cracked Slow Cooker?

No, you cannot fix a ceramic Crock-Pot insert that is cracked or damaged. However, if the outside piece is still in good shape, you can get a replacement insert. However, you might discover that buying a new one isn’t any more expensive.

The crack could be superglued, for example. However, there would be concerns about food safety. Additionally, the repair can eventually fail in the heat.

Additionally, considering how affordable slow cookers are today, why even try to fix a cracked Crock-Pot?

Is it Safe to Leave a Slow Cooker On Overnight?

Yes. You may leave your slow cooker on all night without worrying. Actually, slow cookers are made to be left on for extended periods of time.

Most Crock-Pot users are unsure about how to utilize their appliances. Additionally, they ponder whether it is risk-free to leave a slow cooker running all night.

Don’t you worry!

However, leaving them on all night doesn’t guarantee that the bottom won’t burn if the wrong ingredients are used. It also doesn’t guarantee that liquid will not splatter over your counter if you add too much of it.

However, it’s generally acceptable to leave your slow cooker running while you sleep. Just make sure the cord is not close to the sink or other liquids, and keep it at least 6 inches away from the walls.

I adore my Crock-Pot with a locking lid (link to Amazon) for splatter prevention reasons! When I wake up or return from work, there’s no mess on the counter.

Is it Safe to Leave Your Slow Cooker On While at Work?

Leaving your slow cooker on all day while you are at work or otherwise away from home is entirely acceptable. Set it to low, which is often the setting you would use for 8 or more hours, if possible.

Just ensure that your Crock-Pot is placed on a heat-resistant surface, such as granite worktops.

Finally, place the slow cooker on a completely flat surface. Some countertops might be uneven at times, and you don’t want to risk your Crock-pot toppling over, shattering, or spilling.

You can also seal the lid on some slow cookers, which helps to avoid a mess.

Do you need more assurance of their safety?

Crock-Pot’s FAQ page on their website states the following: “Crock-Pot® Slow Cookers are safe for countertop cooking for extended periods of time. If holding food on the warm setting for a long time, cut back on the cook time accordingly to reduce overcooking.”

Can You Leave a Slow Cooker on Warm All Day?

No. In a slow cooker, you shouldn’t keep uncooked food on warm all day, especially raw meat or shellfish. The warm setting on the majority of Crock-Pot and other slow cooker models is intended to maintain the temperature; it is not intended to heat food or cook uncooked food.

Therefore, simply ensure that your dish is fully cooked (especially important for meats and poultry). THEN you’ll be able to use warm all day.

So, you can set it to warm before you leave for work if, for example, you cooked a brisket all night and want to eat the leftovers for dinner the next day.

All you need to do is make sure there is plenty of sauce on it, and it should keep its temperature all day.

Can You Put a Pyrex Dish in a Slow Cooker?

Yes. You might put a smaller Pyrex dish that can be used in the oven within the ceramic insert of your slow cooker. The Pyrex dish’s lid is not required, but the lid for the slow cooker must be used nonetheless.

This is confirmed by the author of the top-selling slow cooker cookbook in the New York Times, Stephanie O’Dea.

Simply place the ingredients in a small glass baking dish that can be baked in the oven or a Pyrex-style container, and place the dish inside the slow cooker.

Are Slow Cookers Toxic?

No. Slow cookers made nowadays are not hazardous. According to a 2004 study, 20% of slow cookers were releasing trace levels of lead into the food they were cooking. Leaded glaze, on the other hand, was widely used then but is no more.

The research by Bill Gebhardt of Salt Lake City’s KUTV in 2004 is what sparked the worry about slow cookers and toxicity.

He was looking into the possibility of lead exposure from the Crock-Pots heating up and leaching into the food. He discovered that 20% or so of slow cookers were releasing trace levels of lead into the food they were cooking.

In general, ceramic vessels leak 10 times as much lead when heated to 80° than when left unheated. He thought it was worthwhile to look into as slow cookers heat up to around 250°. When heated, acidic foods also have a tendency to release more lead.

Of course, almost all slow cooker brands now declare that their products do not contain leaded glaze, more than 15 years later. Additionally, they claim that their slow cooker complies with the FDA Compliance Policy, which specifies that leach levels up to 1 mcg/mL are considered acceptable.

Fortunately, the FDA keeps track of products that have tested positive for lead, and slow cookers are not among those products.

Can Slow Cookers Catch on Fire?

No, it’s unlikely that a slow cooker will catch fire. Unless the slow cooker is still in fine operating order. But virtually anything that plugs into a wall has a risk of catching fire. So whenever you see that the power cord for the slow cooker is worn, cracked, or broken, always replace it.

After all, we are directing electricity into an object through a wire. The appliance, the wiring, or the plug all have potential points of failure.

So long as your slow cooker is in excellent operating condition with no frayed or damaged cables, you should be good.


We looked into the rumors concerning lead in Crock-Pots, toxicity, and the truths, falsehoods, and myths that circulate online about slow cookers catching fire. However, we also addressed some fundamental safety concerns, such as whether it’s okay to keep a slow cooker on while you go to bed or to work.

But in the end, we were able to discover the precise reason why slow cookers might crack, which means you and your family can stay safe while still enjoying this fantastic small kitchen device!