Posted on 03 September 2007 by

The Definitive Guide to Canning Tomatoes (for Those Afraid of Poisoning Themselves)

Ultimate Guide to Canning Tomatoes (for Those Afraid of Poisoning Themselves)By Tomato Queen

I’ll admit that eying the stacks of gleaming tomato jars in my cabinet has brought almost as much satisfaction over the long, bleak months of winter as eating them in a delicious sauce or stew.

Canning (really, jarring) preserves the texture and flavors of tomatoes like nothing else, and is an affordable way to eat organic and/or heirloom tomatoes year-round.

But make no mistake: canning definitely takes time and equipment.

Those who haven’t canned find it daunting, but have no fear; following a few basic essentials–sterility, acidity, heat–will ensure safe and delicious tomatoes for 1-2 years.

Equipment you’ll need:

– Water Bath with Rack

Tomatoes are acidic enough that you don’t need a pressure cooker. If you don’t own a covered water bath (with rack) and mason jars, they’re often easily scored in rural/farm area garage sales and thrift stores. But for those who don’t have time to scour garage sales or your local craigslist, consider purchasing a water bath on eBay; where you can find a $60 piece of equipment for $16 or so.

– Mason Jars and Bands

I recommend wide-mouthed quart jars for tomatoes, as they’re easier to fill and a good size for cooking. Make sure the jars have no chips or cracks. These, too, you can often find in garage sales and thrift stores; or you can buy sets with rings and lids in mega mart stores and general stores alike. It’s pricy to buy jars new, but worthwhile if you’re using multiple times.

– Lids

These are the rubber-coated discs that the bands secure. These are inexpensive, and should always be used new.

– Canning Tongs

You can also use regular kitchen tongs, but they are unwieldy and take extra care.

– Optional

There are canner’s wands, which are little plastic pen-sized tools with a magnet on the end, for fishing the lids out of hot water.


– Loads of Ripe Tomatoes!
– Canning/pickling salt (or kosher salt). No iodine.
– A pint of fresh lemon juice (bottled works)
– Several basil leaves, cleaned and patted dry

Step 1: Prep

– Fill water bath 2/3rds full and bring water to a boil; then keep at a near-simmer until ready to can. Bring a second large stock pot of water to boil for blanching/peeling later.

– Take clean mason jars and bands and sterilize in the hot water bath by boiling for 3-5 minutes. Remove with tongs and let dry on clean towels.

– Wash all tomatoes thoroughly. Best not to use any tomatoes that have rotten parts at all.

– You might want to separate your tomatoes, by type, variety, and/or color if you care about such things, so that you can use your paste tomatoes for sauces and your green zebras for stews, etc.

– Keep the coated lids in a small pot of hot water on the stove (do not boil).

Step 2: Blanch, Peel and Trim

To keep skins from floating and marring sauces, soups and stews:

– Drop several tomatoes into the stock pot for 30-60 seconds. (This is easiest in a wire basket, but also works to scoop out with a strainer.) Drop into bowl/pot of cold water.

– Then just peel the skins right off.

– Cut the cores and any inedible spots from the tomatoes. Optional: if using paste tomatoes, which are full of pectin and not much juice, you may wish to squeeze/scrape out the seeds from the center.

Step 3: Fill the Jars

Now you’re ready to can!

– Fill the jars with tomatoes, leaving no more than 1 inch of space.

– Use a chopstick or slender rubber spatula to press the tomatoes down so that any air pockets fill with juices. Fill with more tomatoes if need be.

– Top off the jar with 2 Tbsp of lemon juice and a basil leaf to each quart (1 Tbsp of lemon to a pint). If there’s food residue on the top of the jar, wipe off with a clean paper towel.

– Take a clean lid from the lid pot and place onto the filled jar. Screw on the band (no need to make this too tight) and put aside.

– Repeat until you’ve used up all your jars or tomatoes! Jars really do need to be full to seal; you don’t want to can jars with too much air in them.

Step 4: Bathe and Cool

– Bringing the water bath back to boil, bring the rack up so that the handles are resting over the sides of the pot. Load the jars onto the rack and gently lower the rack into the water. The water should cover the jars by at least 1-2 inches.

– Cover the canner and let process for 45 minutes for quarts; 40 minutes for pints.

– Raise the rack back up and carefully remove the hot jars, leaving them to cool on a clean towel (cooling racks are nice, too, on top of towels).

– Repeat with the rest of the jars until all have been canned.

– Let cool: you’ll hear popping noises for the next ½ – 12 hours as the jars cool and seal, one by one. You may wish to remove the bands while the jars dry so as not to get rusty. You can re-screw them on again later, if you’d like, or not; they’re not necessary after your jar has sealed.

If you have any jars that have not sealed after 12 hours, refrigerate! Occasionally through a defect in the lid or jar, you may get one or two that refuse to seal.

Store the jars out of direct sunlight, and your tomatoes and juice should bring you pleasure for months to come.

53 Responses to “The Definitive Guide to Canning Tomatoes (for Those Afraid of Poisoning Themselves)”

  1. susan Says:

    I canned tomato sauce from garden for the first time. I learned if adding lemon juice AFTER I canned. I grew these tomatoes. My recipe called for a 30 minute water bath. However, I slow cooked the tomatoes in the stove for 6 hours before canning. I ready to throw them out for fear if botulism….anyone????

  2. Laura Thomas Says:

    I just canned tomatoes for the first time and the recipe did not call for lemon juice. Should I throw them out? Also one jar of sauce in the middle of the night popped its top a bit it looks like it was bubbling so I threw it out, should I throw the rest out and start over again new?

  3. Jessica Says:

    I canned a batch of 32 cans. About a week later, I lost 5 cans due to bulging and exploding. Should I toss the rest of the cans or is there a way to tell if the others are ok?

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