Food Safety of Glazes and Clay

General information, not legal advice. This page collects what we have found from authorities and manufacturers about the food-contact safety of glazes and clay. Icewood Atelier is not a testing laboratory. Always check the manufacturer's technical data sheet for each glaze, and ask your local food control authority which rules apply to you. Last reviewed: September 2026.


What "food safe" actually means

In the EU, ceramics that come into contact with food must not release harmful amounts of substances into the food. For ceramics, the specific rules are limits for the release of lead and cadmium, set out in Council Directive 84/500/EEC (in Finland, KTM decree 165/2006). The limits depend on the type and size of the vessel. Finland also has national limits for lead, cadmium, chromium and nickel.


The limits apply to the finished, fired piece. "Non-toxic" on a glaze label describes the product itself and is not the same thing as a food-safe result on a fired surface.


Does firing temperature decide it?

No. The rules do not mention firing temperature, and the same limits apply to low-fire and high-fire ceramics. What differs is the clay body and how forgiving the finished piece is.


  • Low-fire clay (earthenware) stays porous even after firing, so liquid can soak into the clay. Every surface that touches food or drink needs to be fully covered by a food-safe glaze that has been fired correctly.
  • Mid- and high-fire clay (stoneware, porcelain) vitrifies and absorbs much less water, which makes it more forgiving. It can still absorb some water, and a high firing does not make a glaze food safe: the glaze itself decides whether metals are released.

Why the glaze must cover everything and be smooth

  • Full coverage: bare or thinly glazed spots on earthenware let liquid soak into the clay body, and they are hard to clean.
  • Intact glaze: cracks (crazing), pinholes and crawling let liquid and bacteria in.
  • Smooth surface: glossy, even surfaces are easy to wash. Rough, textured or very matte surfaces hold on to food residue, which is why some manufacturers and retailers do not recommend matte or satin glazes for tableware.

Layered glazes and decoration

A manufacturer's food-contact statement normally applies to a glaze used on its own, as instructed. A layered combination, a very thick application or added decoration creates a different surface. Decoration on the food-contact surface can also raise metal release, and some glazes are sold as decorative only.


When in doubt, ask the manufacturer whether your exact combination is suitable, test-fire a sample piece, and check that the result is smooth, glossy and free of defects. If you need certainty, have a finished test piece tested for lead and cadmium release at a laboratory.


Checklist for making food-contact ceramics

  • Use glazes that the manufacturer states are suitable for food contact, and follow the stated firing range and number of coats.
  • Glaze all surfaces that touch food or drink, including the rim, evenly.
  • Keep records: glaze recipes or batch numbers, firing logs and the suppliers' data sheets.
  • Inspect every fired piece. Reject anything crazed, pinholed, crawled or rough on the food-contact surface.
  • If a piece is not meant for food, say so clearly in the listing.

Selling handmade ceramics for food use: what is required (Finland / EU)

A ceramic item meant to touch food is a food-contact material. If you make and sell such items, you are a food-contact material operator, and according to the Finnish Food Authority (Ruokavirasto) the main responsibility for the safety and compliance of the finished item lies with the person who makes, imports or markets it. In Finland this usually means:


  1. Notify your municipal food control authority at least four weeks before you start. This also applies to online-only sales. Pure retail resale of finished items does not need this notification. It is made through the Ilppa e-service or with a form from the authority.
  2. Meet the release limits for lead and cadmium (Directive 84/500/EEC, KTM decree 165/2006) and the national limits for lead, cadmium, chromium and nickel. Samples are tested with 4% acetic acid, which represents a worst-case condition, and the intended use cannot be restricted to certain foods to avoid the limits.
  3. Show compliance with testing. The ceramics decree requires the finished product to be shown to comply through laboratory tests. Relief is possible, for example by testing the smallest or a worst-case version of a series of similarly shaped items. How much testing is needed for very small-scale production is assessed case by case, so contact your local environmental health inspector first.
  4. Issue a written declaration of compliance that travels with the ceramics through every stage of trade except the final retail sale, confirming that the lead and cadmium limits are not exceeded. Ruokavirasto recommends updating it at least every three years.
  5. Have written self-monitoring (omavalvonta) and good manufacturing practice, including traceability: know where your materials came from and where your products went.
  6. Labelling: the glass-and-fork symbol is voluntary. You can also state "for food use" or name the item by its use, for example "mug".

Selling to other EU countries. A product that is legally on the market in one EU country can generally be sold in the others, but national rules can differ. The EU is also revising its ceramics rules (lower limits and more metals are under consideration, with possible relief for small artisan producers), and the Netherlands, for example, tightened its requirements for food-contact ceramics from 29 May 2026. Check the rules of the country you sell to.


Questions to ask your glaze supplier

  • Is this glaze suitable for food contact when fired as instructed?
  • Is there a technical data sheet or declaration of compliance?
  • Is my exact combination, clay and firing range covered?

Sources