If you’re busy canning tomatoes (and who in the food preservation world is not?), please be sure to use updated methods. Canning in old pickle jars, canning in a microwave, canning without added lemon juice to acidify the pH for tomatoes, hoping that if the jar seals from the heat of the tomatoes alone then you’re good to go…
all bad news.
Don’t risk the health of your family to save a few bucks.
Check out the National Center for Home Food Preservation’s webpage on how to can tomatoes for the most up-to-date information on canning those beauties safely. It discusses why you need to add lemon juice (tomatoes are right on the borderline for acid content, which can make long-term shelf storage unsafe), why you need to boil the jars, and how to process in easy-to-follow instructions.
What it doesn’t explain is how to keep your kitchen free of tomato juice and seeds splattered all over the place. I’m still working that one out myself.
And if you live in Oregon, don’t forget to give the Master Food Preservation hotline a call if you have a question about preservation or food safety. We’re there to help! The information is listed to the right. Give us a call before you start for best results.
Culinaria Eugenius 
I’ve never been so thankful for the smooth stone backsplash in my kitchen as I was the day I made ketchup and spurted orange tomato guts everywhere.
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I love the daunting photo with this post.
Question: if my recipe has vinegar, is that the same as lemon juice for what it does in the food preserving aspect?
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Thanks, Lelo. I was looking for a Frankenstein tomato feel. Love Photoshop!
Vinegar and lemon juice both add acid to a recipe, and they inhibit pathogen growth, so yes. They have different acidities, though. I can never remember which one is stronger — google will tell you — so you can substitute one way but not the other if you’re using it for canning. Also, lemon impacts the flavor more, in my view.
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