Food safety for functional pieces comes down to four factors: toxicity, clay body vitrification, glaze quality, and usage.

Our pieces are made without lead or cadmium, using a stoneware body with a less than 1% absorption rate, and are fired in a cone 10 reduction kiln. Our glazes are formulated for durability, and fit.

The FDA regulates two materials regarding functional pottery- lead and cadmium. There are strict regulations around the allowable levels of both, and to sell in the US, makers must adhere to those restrictions. However, lead hasn't been used for decades by small batch makers, and even some major dinnerware companies. Cadmium is often used to make red and orange pigments, but because of the FDA's strict regulation these pigments are specially manufactured in a process called encapsulation and labeled to show under which circumstances they are safe to use.

Vitrification is another factor in food safety, and proper vitrification is determined by the percentage of water a clay body absorbs after being fired. This isn't government regulated, and because of that the allowable percentage of water absorption for dishware can vary anywhere from 1-3%. Having a clay body with low absorption prevents water from getting trapped and forming mold- so as close to 0% absorption is ideal. However, modern dishwashing methods are incredibly effective at sanitizing, and a good glaze also helps prevent water absorption.

Having a well fit glaze limits the amount of liquid exposed to the clay body, which can aid in mold prevention even in an absorbent clay body. The caveat being that the piece can still develop mold if the exposed clay is left to sit in water. The inverse of this is true as well- a glaze with cracks (called crazing) can be used on a fully vitrified clay body without risking mold growth.

The other piece of glaze quality is its chemistry. To make a durable and stable glaze it has to be formulated to melt at the correct firing temperature, and have a specific flux ratio. Without getting too much into the chemistry, having this ideal flux ratio creates a glaze that won't leach or break down over time- even in the dishwasher.

The last factor in food safety in ceramics is usage. When looking at flaws in dishware it's important to think about how much contact with liquid a piece will have over its life, as well as whether it will experience temperature changes. For example- a mug that's used for coffee and tea will encounter stress that can exacerbate glaze flaws like crazing and under-vitrified clay, that could eventually lead to mold and bacteria formation. However, an equally flawed plate that never encounters temperature changes and only encounters short periods of being wet when washed is much less likely to run into food safety issues.

All of this is to say that food safety doesn't have to be a scary topic! Bacteria growth is largely mitigated by washing and drying dishes regularly, and the toxic chemicals that would effect consumers are well regulated- most of the risk of raw materials in ceramics is to the makers.