I am making mug cake in a pot using steaming method and I will use normal tea cup. I want to know what precautions I must take so that the cup doesn't break after baking
The only precaution you can take is to have the temperature change happen as slow as possible. This includes:
- don't use cold mugs, start them from room temperature
- put the mugs in the steamer before you have turned it on
- let the mugs cool down slowly
This doesn't mean that you will never have mugs break on you. It can still happen, but it will be a rare occurrence. Just make sure you are only using cups which you can afford to lose, not the most expensive china.
Also: Mugs and cups have handles, which get shaped separately and attached during the production process. The attachment point is then a place with high risk for breaking. So ideally, you would use something without a handle, if you have it. Good choices would be ramekins, or maybe Japanese tea cups, if you find ones that are large enough.
Thermal stress is fairly unlikely to break porcelain you've used to bake something.
Porcelain doesn't automatically break at high temperature (remember, it was "baked" at much higher temperatures than your oven can reach), but may break if part of it is heated to a high temperature while a different part is kept at a lower temperature. Normally you'd need direct, high-flux heat (such as over a burner, or immediately under a broiler element) to cause that.
And if you are steaming the mug, it is absolutely impossible to build up the requisite temperature differential. The stress here is much less than the stress caused by adding boiling water to a room-temperature mug. You'll be fine. Unless you drop the mug.
Yes, don't forget that steaming heats the whole thing quite evenly to a maximum of 100°C (barring pressure cookers of course). Making a hot drink by pouring in boiling water heats it to nearly 100°C , much less evenly, with far more thermal stress on the handle joint; boiling water in a mug in the microwave can get the main bit right to 100°C with the handle cold. No one worries about that– Chris HFeb 15 at 11:51