Thank you for your review and for your feedback. We’re sorry to hear about your disappointing experience. The Staub Lid should rest fitting on the base of the Cocotte with a little steam to escape as not to cause a vacuum effect when the Cocotte reaches a higher temperature. Perhaps using a little more liquid or lowering the heat source and then gradually increasing the heat would help. At ZWILLING, we stand behind the quality of our products. If you have any questions or concerns, please do not hesitate to reach out to our Support Service Center. Here is our website link: https://www.zwilling.com/us/magazine/support-center.html Our dedicated representatives are available to assist you in any way possible.