Food safe describes fired pottery whose glaze and clay are suitable for contact with food and drink: the glaze is durable, fits the clay without crazing, doesn’t leach harmful amounts of metals, and the clay is fired dense.
What Is Food Safe?
A glaze labelled food safe by its maker is only food safe on your pot if it is applied and fired as the maker intends, on a clay it fits. Underfiring, overfiring, thin application or mixing glazes can all change how durable and stable the fired surface is.
Crazing, glaze that doesn’t fully melt, and very porous bodies are the common problems in studio ware. Cracks and pores can harbour bacteria, and poorly melted or unstable glazes may leach colouring metals into acidic food and drinks. Glaze makers generally advise against crazed glazes on food surfaces.
For tableware, choose a clay body fired to its rated cone, glazes rated by their makers for food use, and keep decorative-only glazes, lustres and unknown recipes to the outside of pieces. Commercial laboratories can test glazes for leaching if you sell functional work. If in doubt, label a piece as decorative. Ask your studio which of its glazes are rated for food use, as they usually keep a list on the glazing bench.
This pottery glossary entry from Le Studio Art Space is general educational content. Always follow the clay, glaze and kiln makers’ data for your own materials and equipment.