Crazing is caused by the glaze being under too much tension. This tension occurs when the glaze contracts more than the clay body during cooling. Because glazes are a very thin coating, most will pull apart or craze under very little tension. Crazing can make a food safe glaze unsafe and ruin the look of the piece.

How do you stop ceramics from crazing?

Adding Fluxes to Reduce Crazing

Another way to correct crazing is to add a low-expansion flux material such as talc, which is magnesium silicate. Both magnesium oxide and silica have low expansion; both will decrease the expansion and contraction of the glaze during cooling, to help prevent crazing.

Is it safe to eat off plates with crazing?

Is it safe to eat off cracked dishes? Never eat from a dish or plate that has a crack in it. Cracked dishes can harbor bacteria.