I have not frozen tomatoes in jars, but I regularly freeze various nuts, apple cider, grape juice, freshly rendered lard, leftover soup, green enchilada sauce, bulk yeast, lots of things. Those all get frozen in canning jars. I use the wide mouthed jars for things like apple cider or juice, soup, sauce because freezing causes expansion. Something like nuts or yeast won't expand like soup or juice, clearly. I leave lots of head space, don't tighten the bands until the product is completely frozen and I've had no problems. Actually, I've frozen the nuts and the yeast in well washed and sanitized commercial jars from pickles and jam with no problems.

Annie

Straight sided so your jar doesn’t shatter when your frozen liquid expands. Straight sided pint jars are my most used size. For freezing soups, beans, salsas, sauces as well as canning.

Thanks annie and agmss. Question: Is there something about non-straight-sided glass jars that would break with expansion more than straight? I mean couldn't the ingredients still expand enough at the top.........or does it put too much pressure on that curve? (Sorry, I tend to think a little too much.....haha). Thanks for that tip, Annie, about not tightening the jar until the contents are frozen. :)

catherinet, I've frozen cider in regular mouth canning jars, but I leave plenty of room for expansion, it usually doesn't expand up above the shoulders of the jar. It's kind of my last resort if I'm out of wide mouth jars.

Annie