An example of a cone 10 porcelain that is over mature. It contains too much feldspar and is vitrifying so much that it is beginning to melt. The weight of the handle is pulling the lip into a oval shape, even though the hourglass shape of the piece should offer stability.
Warping happens during the firing of ceramic ware when there is a high degree of vitrification or a shape is unstable. But warping is expected in translucent ware, it is just a factor that must be compensated for.
The term vitrified refers to the fired state of a piece of porcelain or stoneware. Vitrified ware has been fired high enough to make it very strong, hard and dense.
In ceramics, handles need to be applied to many types of ware. There are things to know not just to make them look good, but to be strong, durable, practical.