Your Ceramic Hob’s Glass Is Cracked Or Stained

Are you seeing cracks or stains appearing beneath the glass surface of your electric ceramic hob? There can be various different causes for these, depending on the particular type, shape and location of the crack or stain involved. Discover the various possible reasons why cracks of this sort can appear below.

THE POSSIBLE CAUSES FOR THIS ISSUE:

• The hob is not properly fitted into the worktop

• The hob has been subject to a hard bang or knock

• The hob has been scratched

• Sticky or adhesive substances have not been cleaned off

• There is a stain underneath the glass surface

• The hob is fixed too tightly in place

• One of the plates or rings has overheated

WARNING
Before you do anything to your appliance, make sure you disconnect it from the power supply.
There is a risk of electric shock.
Wear suitable protective gloves if you need to dismantle anything.
There is a risk of getting cut or injured

The hob is not properly fitted into the worktop

If the hole cut into the kitchen worktop is too small, there is a risk this could excessively squeeze and compress the metal casing of the hob. The combination of heat and too little space will cause the glass to break across its width. If you have this kind of crack in your hob, check and reread the installation advice provided by the manufacturer.

The hob has been subject to a hard bang or knock

If your hob has a number of cracks radiating out from a single point, this is probably due to an impact caused by a damaged or overly heavy pan. It could also have been caused by a jar falling on it, as glass-on-glass impacts never have a good outcome.
Did the glass break without it being the direct and immediate result of an impact? The heat-resistant glass on your hob is very strong. However, if it is subjected to an impact, it retains a memory of the incident in its structure and can produce a delayed reaction, even as much as several days later.
After you've cooked on it a few more times, the glass will break due to the strains exerted on it by the heat.
To put it simply and plainly, you need to avoid dropping anything on the glass or subjecting it to any strong impacts.

The hob has been scratched

Does your hob appear to have a crack of some kind, but one that does not extend across its whole surface? A crack cannot just extend for a few centimetres and end in the middle of the glass. Therefore, it is highly likely that what you're seeing is a very deep scratch of the kind often caused by using a damaged pan.

Sticky or adhesive substances have not been cleaned off

Has a piece of glass broken off the top surface of the glass? When this happens, it's normally due to something boiling over, or to splashes of sugar or other similar products. If these kinds of substances are not quickly cleaned off, they subsequently cool and end up sticking to the glass and the pan. When the latter is then lifted up, the substance, which will now be adhesive, may cause a piece of the glass to break off. Therefore, do not wait for substances to cool before cleaning them off.
Important: if your pan is stuck to your ceramic hob surface, do not try to pull it free. Instead, switch the plate/ring back on to heat it up and gently rotate the pan repeatedly left and right to free it.

There is a stain underneath the glass surface

Has a stain appeared underneath the glass on your ceramic hob? Something important to note here is that it's virtually impossible for water or fat/grease to form a dry patch or become congealed and encrusted beneath the glass. More often than not, the stains are actually on the top surface of the glass but are so thin that they give the illusion of being underneath. To check what these patches are and get rid of them, first find a razor blade, or get yourself a ceramic hob scraper designed especially for the task. Angle the blade at 45° to the surface and start scraping the patch. You will see it beginning to disappear.

The hob is fixed too tightly in place

If your hob is equipped with clamps and tightening screws, it is absolutely imperative not to overtighten these, otherwise the glass will be held too tightly in place in the worktop, preventing it from moving slightly. Worktops can sometimes flex and deform horizontally, and a hob that's too tightly fixed in place will be subject to distorting forces that could cause the glass to break at any moment.

A plate or ring has overheated

The thermostats that prevent plates and rings from overheating can sometimes fail or become damaged. This can lead to the glass overheating, or indeed melting, which causes the glass to break in a very specific and particular way, usually inside the plate or ring.
If this occurs, you will first need to change the plate/ring or temperature limiter before thinking about replacing the entire glass surface of your hob.