Mme ZabetI don't do preserves but have used mason jars for general storage and as drinking vessels for decades. I have never had a problem with wide-mouth Ball brand mason jars cracking when used in the freezer until we got this new fridge in February. I always refrigerate them overnight first and leave plenty of expansion room. I can only conclude that for the first time in my adult life (and I'm like 50 now) I have a fridge that actually gets properly cold.