Food Safe & Food-Safe Glazes – What You Need to Know
How to identify food-safe glazes – a guide to safe ceramics for food and drink.
Introduction
Not all glazes are suitable for ceramics that come into contact with food and drink. Food-safe glazes are designed to withstand liquids, acids, cutlery, and everyday use.
Glazes that are not food safe may, for example:
- become discolored when in contact with acidic food
- show marks from cutlery
- crack when exposed to hot water
- develop a rough surface where food and bacteria can accumulate
Food safety is always determined by the surface of the fully fired glaze. However, a glaze can be food safe and still unsuitable for functional ware if the surface is rough, heavily crackled, or difficult to clean.
This guide explains how to identify food-safe glazes and how to work with them safely.
Step by step
- Check the labeling
- Always check the product information before using a glaze on functional ware.
- Glazes that are not food safe are clearly marked in the product description or with a warning symbol:
- Use the correct clear glaze
- Underglazes and engobes usually become food safe only after applying a recommended clear glaze.
- Recommended clear glazes: HF-9, MS-100, SW-004 (clear glazes for stoneware), NTBR, EM-2134 (clear glazes for earthenware).
- Always follow the recommended firing temperatures for the best results.
- Keep your workspace clean
- Do not eat, drink, or smoke while glazing.
- Avoid inhaling sanding dust from glazes, as it may be harmful.
- Keep work surfaces and tools clean.
- Test new combinations
- Always perform test firings before using new glaze combinations on functional ware.
- Check food safety if you mix different brands or glaze systems.
Important terms
- Food Safe: Tested to ensure that the glaze does not release harmful substances when fired correctly
- Dinnerware Safe: Provides a durable surface suitable for plates, mugs, and bowls.
Tips
- Do not focus only on appearance – functionality is just as important for functional ware.
- Document which glazes and glaze combinations work well.
- Always run tests when trying new materials.
A simple way to test food safety is to place a slice of lemon on the glazed surface overnight and check if the surface changes. You can also test durability by pouring hot water over the piece and gently using cutlery on the surface. If the surface does not change, it indicates that the glaze has good resistance to acids, heat, and wear.
Summary
Knowing which glaze is food safe saves time, money, and frustration. Always check the labeling and perform test firings.
On the website, you can filter food-safe glazes under Properties.