I remember when I was little watching my mother make jellies, relishes and preserves. She used every little jar she could find that had a screw-on lid. Pickle jars, preserve jars, and condiment jars all got a second life holding the treasures that came out of her large canning pot. The cutest, though, were the baby food jars. Every jar got a "cap" of wax poured on top to seal it and lids were screwed on and allowed to seal before it was decorated.
Tiny Jars of Tasty Gifts
Back then, newspapers were delivered rolled up with a rubber band holding them into a neat tube that newspaper boys tossed into your yard. My mother would cut squares of fabric and attach them across the baby food jar tops with saved rubber bands. She would then glue on a Christmas label, and off they would go to neighbors and friends. Maybe jars were made better back then, but now, you're told not to reuse those jars for canning.
Why Shouldn't You Reuse Baby Food Jars for Canning?
The prevailing wisdom is that baby food jar glass is too thin, which makes it more likely to explode during filling. Also, the lids won't make another tight seal once they have been opened. This makes sense for jars that need boiling water baths, but what about preserves and jellies you just pour into the jar?
My Experience with Reusing Jars
I've reused baby food jars for canning, but I wouldn't do it now. I believe that in the days when my older son was eating baby food, the jars and lids were more substantial, or I remember them being so. Today's jars are made in another country and are too cheaply made for me to consider safe.
When I did use them, I warmed them first in very warm water, and I only used them for preserves or relishes that didn't need a boiling water bath. I poured wax into the caps to create a seal. I gave them as gifts, and no one ever told me they got sick from them, so I can only assume that they were eaten quickly, since the jars were so small. Maybe I just got lucky.
Better Safe Than Sorry
I don't recommend reusing any kind of grocery store jar for canning. Canning jars are processed differently and the glass is denser and less likely to break. Grocery store jars aren't strong enough to withstand the heat and pressure of canning. Plus, if your reused jar doesn't seal properly, bacteria can build up rather rapidly in the contents, and there isn't always a sign, like a bulged top or mold.
In my grandmother and mother's day, things were very different than they are now. My mother grew up during the depression, and I suppose that may explain the reusing everything and never throwing anything away. Now, I have all sizes and types of real canning jars and buy new lids every year. If I used baby food jars, I might not poison myself or anyone else, but why take the chance? A few pennies saved is not worth the risk that you may make yourself, your family or others ill.
If you want to learn more about canning, the U.S. Department of Agriculture has a downloadable PDF called "Complete Guide to Home Canning" that is free to download online .