You need at least 1/2 inch of head space.
Steve
"rile" wrote in message
oups.com...
We finally might have enough tomatoes this year to start canning tomato
juice again. My wife and I are at a disagreement though. She always
seems to fret over the jars not sealing. I've said that she fills them
too much. I claim that she needs to leave some air at the top, at
least to the bottom of the lid edge. She disagrees. Any ideas?