How to Can Tomatoes at Home — Safely!

By Lena Anken Sexton
Published on July 1, 1985
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ILLUSTRATION: MOTHER EARTH NEWS STAFF
Use these four easy home-canning steps to ensure your tomatoes are both scrumptious and safe.

I canned my first batch of homegrown produce 58 years ago, when I was just nine years old. Countless quart and pint jars later, the tomato remains my favorite garden product to put up … mostly because it’s my favorite to eat.

I shudder, however, when I think of how many people in this country are innocently using unsafe tomato-canning techniques. For instance, if you are following a canning guide that’s from 1983 or before, you may not be aware that the raw-pack, boiling-water-bath method — commonly used over the past several decades — is no longer considered safe for tomatoes. And I can’t even count the number of times I’ve heard people say — to my horror — that they still can their tomatoes the old-fashioned, open-kettle way because “they never hurt my grandmother or my mother, and they won’t hurt me.”

Granted, botulism poisoning from canned tomatoes is relatively rare — but when you’re talking about a disease that destroys human life, rare isn’t enough. I have seen the ravages of the deadly Clostridium botulinum. It is an insidious killer, for it reveals no clues to its presence: no mold, no odor, no color or taste change. It will grow and thrive in a perfectly sealed (but insufficiently heated) canning jar.

And although tomatoes are generally considered a high-acid food — one that supposedly presents a hostile environment for botulinum — the fact is that their pH can vary greatly, not only by variety, but by a whole range of other factors. Too-green tomatoes, overripe tomatoes, tomatoes from pulled vines, bruised tomatoes, low-acid-type tomatoes, tomatoes grown in low-acid soil … all have been blamed for producing “killer jars.”

Finally, after years of debate (and the controversy continues), the U.S. Department of Agriculture changed its recommendations for canning tomatoes in 1985: The USDA has dropped the cold-pack, boiling-water-bath method from its list of approved techniques … recommended that an acidifier be added to tomato products (particularly low-acid and very ripe produce) … and lengthened its processing-time guidelines for the hot-pack, boiling-water-bath method (more information below).

As for me … well, I hot-pack all my tomatoes and process them in sterile jars in a pressure canner at 15 pounds pressure for 10 minutes — which exceeds even the new USDA guidelines. Why? Because, after years of experience, I’ve decided that taking chances is a fool’s game. As far as I’m concerned, there’s just no such thing as too safe when it comes to the food my family and friends will eat!

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