Steam holes in clay cookware lids.

[Linda Perez]

Does anyone know the rationale of when to have and when not to have a steam hole in the lid of clay cookware? I have been researching and making clay cookware from various cultures and have no idea when to include a steam hole in the lid. Thanks.

[PaulOuzts]

If fluids are inside the pot and the temperature expected is at or above 212F...have a steam release hole otherwise the lid will attempt to rise. 1/4" in diameter should be sufficient.