Skip to Content

Cracked Ceramic Cup – Is it Safe to Use?  

It won’t be surprising if you have a ceramic cup in your cupboard that is slightly chipped or even seems to be cracked inside.

These things happen all the time.

Did you know that even a small crack in a ceramic cup can be dangerous?

Cracked Ceramic Cup – Is it Safe to Use? 

A crack in the ceramic at the bottom of your cup is not safe because bacteria can become lodged there that cannot be got rid of in a normal washing process, even in a dishwasher. It’s also possible that a tiny shard of ceramic could escape from the crack into the cup and cause problems if it is drunk with the coffee. Some ceramics contain metals, which can also leach out through the crack.

Cracked Ceramic Cup - Is it Safe to Use?
Cracked Ceramic Cup – Is it Safe to Use?

Is my cup cracked, or is it just crazing?

Crazing is a common feature of ceramic dishes and mugs. It is the result of the glaze on a piece of crockery and the basic clay expanding at different paces.

This causes hairline cracks to develop in the glaze.

Generally, crazing is not a problem, because it is a very superficial feature that is quite common.

However, some crazing can be deeper than others, which makes it similar to cracks in the glaze.

A crack in a mug is a single line that indicates damage to the glaze and possibly the underlying clay.

This type of flaw is usually caused by some kind of damage and runs deeper than the typical cracks associated with crazing.

What is the danger of cracks in a ceramic cup?

Although a crack in the interior of a ceramic mug may appear to be quite inconsequential, it can actually be the site for problems to emerge in the mug that can affect you.

There may be a build-up of bacteria in the crack, metals can leach out of the glaze through the crack, or tiny flakes of the ceramic can move into the mug itself. All of these can potentially be harmful if you drink out of the mug.

Build-up of bacteria in cracked ceramic cup

Cracks in a ceramic mug, especially a single crack, not only crazing, are sites where bacteria can potentially gather. Because the cracks are so thin, it is not easy to clean them properly and the bacteria will thrive and increase.

When this happens it is possible that some bacteria will enter the coffee you drink from the mug and can affect you.

Bacteria can be lodged in a cracked ceramic cup. It is therefore not safe to use
Bacteria can be lodged in a cracked ceramic cup. It is therefore not safe to use

What harm can bacteria do?

Experiments with cracked ceramics have identified two types of bacteria that can occur in the cracks in something like your mug: Acinetobacter and Pseudomonas

Acinetobacter is potentially harmful, but the minuscule amounts living in the cracks don’t have any awful effects.

People can suffer from upset stomachs more than anything.

Pseudomonas is potentially more generally harmful. Again, though, the amounts that can escape from the cracks into your coffee are unlikely to cause much harm.

Given that there is even the slightest possibility of bacteria getting into your coffee from the crack, then it is possibly safer to avoid using a ceramic mug with a crack inside it.

What metals does ceramic glaze contain?

Ceramic glaze can contain little bits of metal oxides such as potassium and sodium. These are not necessarily harmful to us.

However, the glaze on older ceramic crockery can contain some lead, which can be harmful if it gets into your body.

For this reason, you should avoid the possibility of any lead leaching into your hot drinks. This is only likely to happen if the lead can get out through a crack in the glaze.

Can sharp flakes escape from a crack in a ceramic cup?

When a piece of ceramic cracks, there is always the possibility that sharp flakes can escape. This is especially possible if the crack is caused by some trauma to the cup and is quite recent.

Any sharpish, foreign item can potentially cause damage to your digestive tract and it is better to avoid swallowing any of them, no matter how small. This means getting rid of any mug that has a crack in it.

Is a cracked ceramic cup likely to break?

Crazing in the glaze of a cup doesn’t necessarily mean that the cup is weakened and is likely to break.

A crack is different, though, because it’s often a spot of weakness in the cup, which may crack further or break completely.

This is potentially dangerous, as a broken cup can have sharp edges that may cut someone.

Frequently Asked Questions About Cracked Ceramic Cup

Why are bacteria a potential danger in a cracked mug?

Microscopic bacteria can find a home just about anywhere, but particularly in areas they can latch onto. A crack in your ceramic mug offers a good place for this, and they can stay there for a long time. Some bacteria can escape and get into your coffee, then be swallowed.

Why are flakes of ceramic potentially harmful?

Any hard and sharp item can potentially cause harm, because it can cut into your stomach or another part of your digestive system. Flakes of ceramic in a cracked mug are not likely to be large enough to cause any harm.

Conclusion About Cracked Ceramic Cup

A cracked ceramic cup is not always a problem, and you could use it for a long time without any issues.

However, there are some hidden threats, which could affect you before you know it.

The long and the short of it is that it’s better to avoid using a cup that appears to be cracked inside.

Or you can attempt to repair a cracked ceramic pot following the tips&tricks over at Spinning Pots.