doing hot bath for sauerkraut.  Cleaning jar rims, adding more salt water to 1 inch of top, putting new lids and rings on jars.  Screwing rings on tight.  Put jars in canning, filling with cold water and bring to rolling boil for 30 minutes.  When we turn off stove and remove lid to canner we are seeing most of the lids have bent in upward position.  WHAT IS MAKING THIS HAPPEN? 
Adding cold liquids to a hot enameled pan is not going to crack the enamel, you can add a cold beer to a dish without worrying about your cookware. The main thing to keep in mind when adding cold liquids is that it will bring the temperature down below your desired cooking temperature, you will need to either crank up the heat to bring it back up to the desired temperature quickly or lengthen the overall cooking time.  