Material

Glazed stoneware

Family: Ceramic

What it is

Glazed stoneware is fired clay with a glass-like glaze over it, the surface of most mugs, plates and ceramic drippers. The glaze is what touches your food, so a lead and cadmium test on that glaze is the one document worth asking for.

Why it matters in your kitchen

Picture your morning coffee in a favorite mug. The coffee touches only the glaze, so what's in the glaze, and how it was fired, matters more than the clay underneath.

FDA sets limits for lead that can be drawn out of ceramic foodware, and it has said pottery that leaches lead shouldn't be labeled "lead free." A recipe statement isn't a test, which is why we list glazed ceramics only with test documentation.

Chips change things. A chip exposes the clay body, which wasn't made to be the food surface.

Good at

A sealed, glassy surface. Coffee and sauces sit on glaze instead of raw clay, so it washes up like a plate.
A real test exists. ASTM C738 measures the lead and cadmium that acetic acid draws out of a glazed surface, so a maker can show you numbers.
Everyday dishes. Mugs, plates, bowls and drippers, in any color the glaze allows.

Watch for

It chips. Retire a piece with a chip where food or lips touch, or move it to holding pens and keys.
"Lead-free" without a test. FDA says leaching pottery shouldn't carry that label. Ask for the test report, not the recipe.
Decorative pieces aren't for food. FDA requires a warning label on ornamental ceramicware with lead that isn't meant for food. Keep those off the table.
Dishwasher and microwave rules vary. Follow the maker's guidance for each piece.

Who it suits

Good for you if you want everyday mugs and dishes that wash easily, from a maker who'll share a lead and cadmium test. Skip pieces with no test, chipped glaze, or a decorative-only label.

In short. Glazed stoneware puts a glassy glaze between clay and food, and the lead and cadmium test on that glaze is the fact to ask for.

Unglazed pieces have their own page: unglazed stoneware. For what research has and hasn't shown about ceramics and lead testing, see our guide.

Where it is used

Mugs and cups
Plates and bowls
Ceramic pour-over drippers

How to care for it

Follow the maker's dishwasher and microwave guidance.
Retire or repurpose a piece once the glaze chips where food touches.

What the label tells you

Lead and cadmium test results, when a report is on file (ASTM C738 extraction, compared with FDA's limits).

What it doesn't tell you

Never "lead-free" on the strength of a recipe statement. FDA may treat that label as misleading where lead can be extracted.
It doesn't support health promises beyond the test result.

Material pages describe the material in general. The profile on each product page says what we know about that product and how we know it.