Should you glaze a ceramic deep dish before baking in it?

It is generally not recommended to glaze a ceramic deep dish before baking in it. Here's why:

1. Glaze Composition: Glazes used in ceramics are typically composed of various minerals and chemicals, including silica, feldspar, and metal oxides. These materials are designed to adhere to the ceramic surface and create a smooth, glossy finish after firing at high temperatures. While glazes are safe for use in contact with food, it's important to ensure that the glaze is properly fired before coming into contact with food.

2. Direct Heat: When a glazed ceramic deep dish is placed directly in a hot oven, the glaze may not withstand the sudden temperature change. This can cause the glaze to crack or blister, compromising its integrity and potentially leaching harmful chemicals into the food. Glazed ceramic dishes are generally not designed for direct heat and may be more suitable for serving or decorative purposes.

3. Unintended Chemical Reactions: Certain glazes, especially those containing lead or cadmium, may release toxic fumes when subjected to high temperatures. Over time, these fumes can contaminate the food and pose a health risk if consumed. Older or vintage glazed ceramic dishes should be handled with caution and should not be used for cooking without confirming the safety of the glaze.

Instead, it's best to use ceramic dishes that are specifically designed for baking and are labeled as oven-safe. These dishes are made with materials that are resistant to heat and do not require glazing before use. Additionally, they are often coated with a protective layer that prevents absorption and staining.