The Qualities of Ceramic Pots

Appears in
On Food and Cooking

By Harold McGee

Published 2004

  • About
The outstanding characteristic of ceramic materials is chemical stability: they are unreactive, resist corrosion, and don’t affect the flavor or other qualities of foods. (One exception to this rule is the fact that clays and glazes sometimes contain lead, which is a nerve poison, and which can be leached out into acidic foods. Imported ceramic containers made with high-lead clays or glazes still occasionally cause cases of lead poisoning.) Ceramic pots tend to be used only in slow, uniform cooking processes, especially oven baking and braising, because direct high heat can shatter them. Heat-resistant forms of glass incorporate an oxide of boron that has the effect of reducing thermal expansion by a factor of about 3, and for this reason are less affected by thermal shock, though they’re still not immune.