FAQ: Is It Food Safe? What About Heavy Metals?

It is the right question to ask about any ceramic you'll drink from daily: is the glaze safe? Here is the honest, science-based answer.

What Food-Safe Means

A glaze is food-safe when it is fully vitrified — fired to a glassy state that cannot leach metals into food or drink — and when it contains no toxic colorants. Genuine Jian Zhan glazes are compounded from natural mineral ores and wood ash; they contain no cadmium or lead-based pigments, which are the toxic culprits in some cheap commercial ware.

The Iron Factor

Jian Zhan glazes are iron-based — and iron is not only safe but beneficial. The high iron content is what gives the glaze its depth and the cup its water-softening properties. Iron leached in trace amounts is nutritionally neutral to positive; it is not a heavy-metal hazard.

How We Verify

Our studio partners fire their glazes at 1300°C, which fully vitrifies the surface — an inherently safer process than low-fire industrial ware, which can remain porous. We also require food-safety compliance from every studio we work with, and our pieces are inspected for glaze defects that could compromise the surface.

Practical Advice

Wash new pieces before first use (the awakening ritual covers this). Never microwave your Jian Zhan — thermal shock is a physical risk, not a chemical one. Used normally, a genuine Jian Zhan is as safe as any high-fired ceramic — and far safer than many cheap imported mugs.