Tips for Tomato Canning Season

August 13, 2012(updated on October 3, 2018)

heirloom seconds

There’s been a rapid up-tick in questions about tomato preservation in the last week, so I thought I’d take a few minutes to gather all my tomato-centric posts in one place. Before you shoot me an email with a tomato query, take a look through these posts because your answer may be there.

Canning Whole Peeled Tomatoes – A basic tutorial that will walk you through the steps of canning whole tomatoes packed in their own juices. This is my preferred method for canning tomatoes for use throughout the year.

Tomato Canning 101 – If you’re dealing with floating tomatoes, a separated product or loss of liquid during processing, read this post in order to set your worries to rest.

Did your Sungolds, grape tomatoes and cherries do really well this year? Check out this post which details five ways you can preserve small tomatoes. On the flipside, if your bigger tomatoes are doing well, here are five ways to put them up.

Last summer, I made tomato paste for the first time. I wasn’t too keen on when I first did it, but I must confess, it’s been incredibly useful throughout this year. So much so, that I’m thinking of biting the bullet and doing it again (if I’m able to get a really good deal on tomatoes in the next few weeks).

Finally, no tomato post is complete without mention of my two favorite tomato jams. The classic and the one featuring yellow tomatoes and basil. Both are delicious.

In other news, the winner of the Mountain Rose Herbs giveaway is commenter #717, Elizabeth Dalton. Thanks to all who entered!

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42 thoughts on "Tips for Tomato Canning Season"

  • If you have a crockpot.. use it to reduce the tomatoes down the day before you want to can them. It makes life a whole lot easier.
    Also, it look like you have a VitaMix.. use that to puree your tomatoes, skipping the work of de-skinning, & milling the tomatoes. If you zip them in there long enough, all the seeds as well as skin disappear.

  • Yay tomato canning! I’ve been buying lots of tomatoes from the sort-outs bin at the farmer’s market and processing them into plain all-tomato sauce–great, but clearly I need to branch out! Plus I have a gigantic sungold plant with baby tomatoes just starting to ripen–I’m totally going to be drowning in them in about two weeks. My freezer is going to be so full. πŸ™‚

  • I just spent the entirety of last weekend canning, primarily, tomatoes (tomato sauce actually – two of your recipes from your beautiful book!). I was a little nervous about the separation… it’s something you don’t really see in commercial products, so I was curious about it in the homemade.

    It was an enlightening weekend, for sure. It was my first real attempt at canning staples en masse (previously, I’d dabbled in jams, pickles, and apple sauce), and though I’m glad that I did it, I was having a little bit of self-doubt about whether or not it is worth the effort. (I wrote a post about the full nervous breakdown.)

    Thanks for your post. I don’t have a co-conspirator in my canning aspirations here, so it’s nice to have a voice from a fellow blogger keeping me reassured. Thanks for all you do!!

  • Your post couldn’t be more timely! I was up to my ears in tomatoes and decided to try my hand at them for the first time. I used the recipe for basic tomato sauce from the Ball Complete Guide to Home Preserving book, however it didn’t say to peel and seed the tomatoes before cooking them but to strain those out later. What I was left with was basically a thin tomato juice. I had to cook it down for more than an hour before it reached the constency I was looking for. Do you think I did something wrong? I might just concasse the ‘maters first next time.

    1. Not Marisa but… I made tomato sauce last year from the same book and had the same experience. It took a long time cooking to get it “saucy.” I vowed to make crushed or whole tomatoes in the future. Part of my problem was that I used a variety of my homegrown tomatoes most of which were not paste/romas. Regular (non-paste) tomatoes have more liquid and seeds so thinner sauce.

  • We’re getting so many tomatoes in our CSA this year (does that sound like a complaint? Because it’s absolutely NOT!) that I’m having trouble keeping up. What a timely post… I think I might attempt a tomato jam. Yummy!

  • My CSA was offering an unlimited amount of tomato seconds today, so I asked hubby to stop on his way home from work and get some. He got some all right – about 30 lbs of them! I’ve currently got 3 pots (each with a double batch) of tomato jam simmering on the stove. I think we’ll be up until midnight to finish the canning process. The best part is that my husband keeps coming over and telling me how absolutely wonderful the house smells!!

  • This summer has marked the beginning of my explorations in canning (it started last month when I found sweet cherries for $1.99/lb and made your recipes for cherry bounce and pickled sweet cherries). This past weekend was partly devoted to your tomato jam recipe, and I have to say that I was totally wowed by the flavor. I ended up with 11 4-oz jars and I can’t wait to eat some (and give some away, but only to people who I REALLY like). Today is garlic dill pickle day, and I’m killing time as I wait for my (giant) canning pot to boil. Thanks for all the great recipes and the straightforward way you present them!!

  • Our tomatoes are finally ripening in Vermont, so it’s nice to have a bunch of information all in one place. I think we are going to try to can some whole tomatoes, although we will probably use the pressure cooker we just bought. Also want to dry some cherry tomatoes and possibly do some salsa.

  • I am new at canning and was looking for a simple salsa recipe that I can use my fresh garden tomatoes. I would like to be able to use sugar also in the recipe. Any ideas? I am at a lost for which recipe to try. Thank you for any help.

  • I processed two pints of whole tomatoes with no extra liquid recently. After the long 85 minute boiling point, enough of the water had evaporated that the jars were no longer covered. They were covered by at least an inch at the beginning, and I did use a lid for the pot.

    I’ve been trying to find an answer everywhere on if I should toss them or not.

    Also how can I prevent this in the future?

    1. Did you have a lid on the pot? If you did and still lost liquid, you can always add some boiling water to the pot to raise the volume back up.

  • I have some white stuff floating inmy tomatoes? What the heck? I can’t find anything online in regards to this. I pressure canned them according to the recipe. I’m afraid to use the and want to replace them ASAP if they are bad. Any guidance?

  • This is the first time I have written anything to food in jars. I love your website! When
    have a bumper crop of tomatoes I always make taco sauce and salsa . We love mexican
    food and its nice to have homemade spiced to your taste. For taco sauce just peel and
    chop tomatoes, crush with potato masher, add chopped onion, chili powder, comino
    [cumin], some finely minced hot chili pepper, small amount vinegar, dab of sugar, salt
    to tast. cook down to proper consistency, put in sterilizes jars. I always water bath can
    mine to be safe. This recipe is good for tacos, Spanish rice, tostadas and many other
    I misplaced my salsa recipe momentarily so will post it latrt

  • I love your site. This tomato year has been phenomenal for us in Warrenton, MO. My father ‘n law started 150+ various tomato plants from seed. All different varieties though I prefer Roma for canning. It was a test for different types. We were going to do it right this year and leave enough room for tilling. But when the temps reached 100+ degrees, my husband gave up on tilling and weeding which actually helped us by shading the plants. So far we harvested 1500+lbs of organic tomatoes. Still lots more to ripen. I’ve canned everything, my neighbor/friend is also canned out. I’ve donated over 400lbs to the Missionaries of Charity shelter (Mother Teresa order) for their soup kitchen. Unbelievable. But I like canning regular crushed tomatoes that I cook down a bit (1/2 hour) to avoid the water on the bottom as they being most all-purpose type to do anything with. I’ve also made sauce, Mrs Wages salsa, barbecue sauce, yellow pear tomato and ginger jam. Next year I want to can and simplify it with the vitamix after removing the bad spots. I’ve read a bit about it. I figure not only easier but more nutrients. I don’t like cooking a thick sauce because as you mentioned, it becomes bitter. Any more info on canning experience using the vitamix would be wonderful.

  • Hi Marisa,

    Great info, thank you!! I just did 7 quart jars of garden tomatoes yesterday. Whole tomatoes, that after processing floated to the top, like some of the photos I have seen. Some seem to have broken apart, I think I left them in the boiling water before peeling them too long.
    I also had two buckled lids, and some siphoning, as the water smells like tomato juice.

    I used the pressure cooker. Added 1/2 tsp citric acid AND 1tsp salt per quart jar. I put them in the jar with 1/2 inch headspace, hubby did the lids and bands, but I do believe he overtightened the bands, as two did buckle. However, 5 did not.

    Per the presto canner booklet, we put the jars in the canner, brought up the heat till the steam emitted from the spout, put on the weight (10lbs and 25 minutes) and let the weight rock..

    We then let the canner sit ,off the heat overnight without opening it. It said to let the pressure deregulate without removing the weight or lid, and cool..

    1) can i use the tomatoes even if they siphoned, if the lids are still indented on the non buckled ones? How do you check for a tight seal, and if there is food residue/siphoning they are still ok? (paranoid)

    2) but now that two are obviously buckled is it too late to save them since its been over 15 hours? Toss them?

    3)We use an electric stove and did have to adjust the temp a few times as the rocker would get rather aggressive and the booklet said “gentle rocking”. Not sure that actually mattered now, as the siphoning is from change in temp, right?

    Seems so complicated with tomatoes. And of course, it’s one of the most bountiful garden items. Murphy’s law. LOL.


    1. Heidi, if you use a pressure canner to process your tomatoes, you don’t have to add acid to them. The pressure canner makes the issue of acid levels moot. Have you seen my tomato trouble-shooting post?

      1. As long as the seals are good and strong, you can still use the jars that siphoned. Test the seals by removing the rings, grasping the edges of the lid and gently lifting up an inch. If you can suspend the jar holding only onto the lid, your seal is good.

      2. You can put the buckled jars in the fridge and use them in the next few days.

      3. The siphoning has more to do with trapped air bubbles inside the tomatoes than it has anything to do with temperature changes. Do try to keep the pressure regulated, though.

  • Hi Marisa,

    I love your site! It’s been very helpful as I start my canning journey. πŸ™‚

    I recently canned about 40lbs of tomatoes. I read a couple dozen different “recipes” online beforehand, but I’m not feeling so confident in what I did.. I couldn’t quite find what I wanted, so I improvised. Probably not a good idea for a novice canner!

    I cored, blanched, peeled, and then diced the tomatoes, slowly adding them to a large pot and simmering them for about three hours until they’d reduced by about 1/3. Ladled the tomatoes into my pint jars, added a tbsp of Lemon juice and processed for about 50 minutes.

    They’ve all sealed well.. (phew) but I’m concerned I did something wrong. The closest recipe’s I’ve found say to simmer for 5 minutes and away you go, or to strain/mill out the seeds. Are there any issues with not getting rid of the seeds, and/or simmering a lot longer?

    How do you determine the appropriate processing times? The two closest recipe’s I’ve found (USDAs ‘Standard Tomato Sauce’ and Bernardin’s ‘Tomato Sauce’) are both 35 minutes + adjustment for your elevation (or 45 minutes for mine). However some very similar recipes required substantially longer! πŸ™

    Yikes, this got long.. sorry! Any insight is very much appreciated.

    Thank you!

    1. I use the processing times recommended by the National Center for Home Food Preservation. It’s the gold standard for home canning.

  • Thanks for the great tips. I just canned tomatoes for the first time ever this past weekend and they turned out great! I processed longer because I’m at high altitude in Boulder, CO. I used the Colorado State University guide to high altitude food preparation and increased the time by two minutes per 1,000 ft above sea level.

  • HELP!!!!
    (This was a reply to a comment above, just wanted to make sure you saw it!)
    I have the same stuff! It looks like little worms! I threw the last batch of juice away (that would have made a wonderful 7qts!) when I noticed this. I just started filling the jars with the latest batch, making sure the tomotoes were perfect with no cracks or holes. To me, that would indicate worm entry places. I still have those white things! I don’t want to keep tossing out the juice if it’s actually part of the tomato. HELP!!

    1. I have the little worm looking things in my sauce as well. I have seen it in peas. I’m thinking it is part of tomatoes. Let me know what you found out. I hate to throw mine out as well.

    2. Did you use a food mill to process your tomatoes? I did. I have the same thing, was thinking maybe worms, but if you have another batch with all skin intact and still have it, I wonder if the food mill partly ground up the seeds, and that’s what we’re seeing?

    3. Hi! Figured out it is the seeds! When the tomato seeds are pressed through the food mill- sometimes the seed splits and those little white things are what is inside! Kind of like new growth from a seed-

      1. Wish I would have seen this before I threw out a whole pot of soup! My husband was convinced there were worms in the meat. gross huh? But now I know it was probably from the crushed tomatoes. That was some good tomatoes ruined too!

        1. Greets,

          Same thing here. Except I found them in organic canned tomatoes purchased from the store.

          Turns out these worms were “likely” not worms, at least I could find no tomatoe pest resembling these small worms. What I did find was a photo of tomato stem rootlets. These look exactly like the “worms” I found in my sauce.

          So tonight I chow.

          I must admit I coooked the heck out of the sauce, just to make sure I wasnt gonna get parasites…

      2. Thank you! I just opened a can of crushed tomatoes and wasn’t going to use them because of little white “worm looking” things in it.

  • Hi. I have your book and last night I tried canning tomatoes for the first time using your marinara recipe. In my excitement and self-pride, I forgot to add the lemon juice to my jars. I didn’t realize it until after I had finished processing. Since I am new to canning, I have no idea if anything can be done…can I re-can it? I understand the lemon/acidity is important to tomato canning, but don’t understand all the chemistry behind it. Does it just have to do with giving a safe shelf life? Should this batch be refrigerated then? HELP! πŸ™‚

    1. Kaylene, since you just canned them last night, you could open the jars, bring the marinara back up to a boil and recan the sauce with the addition of lemon juice. The lemon juice is necessary to ensure that the contents of the jars have enough acid in them to prevent the growth of the botulism toxin.

  • Not sure if you’re still monitoring this post, but I could use your help. I’m cooking down a bushel of tomatoes and they smell gross, like cigarettes. Any idea why? I don’t think I want to can these…

  • (Please Readddddddddd)!!!!!

    I I canned my home made salsa I in June now it’s like October I believe I saw a larvi inside please tell me it’s not. I added two table spoons of lemon juice to my salsa then took the air out last canned it. I thought it was garlic but got a little close and it’s A schrunchy thing. Please help me to understand what this was and could it happen again and why????? Please say it’s not a worm.

    1. If you processed your salsa properly, I can’t imagine that there are worms in your salsa. Sometimes tomatoes produce little while sprouts in their interior while they’re fresh. It could be that. However, the rule of thumb is if you doubt the safety of your preserve, it’s best to throw it out.

      1. I had the same problem just now. Little worm like white things. Somebody on here mentioned that it was part of the tomato seed. I had put my cooked down tomatoes through the food mill and noticed all these white little “worms”! My husband just now cut some of the seeds and squeezed them and sure enough a white little worm like thing pops out! It is part of the seed. Probably the germination part! Big relief, because I knew I had used good clean tomatoes with no worm holes or splits. Another thing, if it was worms, you shouldn’t see them after the canning process because the’d turn to mush!