Canning 101: Why You Can’t Can Your Family’s Tomato Sauce

full jar

Tomorrow is the first day of September, and with it comes all those traditional end-of-summer events, including tomato canning season (at least here in the mid-Atlantic where I live). Because the yearly tomato glut is finally beginning to arrive, I’ve been getting a number of questions about how to safely can tomatoes.

The most frequent question I get is from people wondering if they can boiling water bath process their favorite spaghetti sauce recipe. You know, the kind that has plenty of garlic, onions, basil, olive oil and sometimes even a few peppers.

Sadly, I always end up delivering disappointing news. You really can’t just can your family recipe. Anything canned in a boiling water bath needs to be high acid (for the science minded types, this means that it has to have a pH of 4.5 or below). This is because botulism cannot grow in high acid environments. However, tomatoes are in the grey zone, typically having a pH right around 4.5. Because of this, tomatoes need to be acidified when canned, so that the acid levels are pushed into the safe zone and the pH becomes something lower than 4.5. That’s why my instructions (and all other good ones you’ll find) for canning whole tomatoes includes two tablespoons of bottled lemon juice per jar (you can also use citric acid if you prefer).

When you make spaghetti sauce, one typically adds a slew of ingredients that, while delicious, lower the acid to seriously unsafe levels. Unless your family spaghetti sauce recipe contains several cups of red wine vinegar, it will be too low in acid to be canned in a boiling water bath.

Most canning information will repeatedly remind you that it’s incredibly important to follow tested recipes. While I will occasionally play around a bit with jams and pickles (and I only do this because I know which aspects can’t be monkeyed with), even I never deviate when it comes to acidifying my tomatoes. I always follow the instructions in either the Ball Blue Book or So Easy to Preserve when I want to preserve tomato sauce, soup and salsas.

The one caveat I have to offer is that if you have a pressure canner, you may be able to preserve your beloved sauce recipe (just so you know, any recipe that includes meat MUST be pressure canned). Pressure canners raise the internal temperature of your jars to temperatures in the neighborhood of 240 degrees, which is high enough to kill off any botulism spores that may exist in your food. However, you should still consult recipes that have been tested using a pressure canner to determine processing time and pressure.

The good news here is that there are plenty of safe, tested tomato recipes that are designed for canning. Let’s hear about your favorites!

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395 Responses to Canning 101: Why You Can’t Can Your Family’s Tomato Sauce

  1. 201
    Eileen says:

    pH test?
    IF the issue with water bath canning tomatoe sauce is the pH can we test the pH and add enough citric acid to get the pH <4.5 and then use the water bath. I know you keep saying meat sauces need to be pressure canned, but I can't figure out why if you can get the pH of the sauce <4.5, or when you add the meat is there more than just the pH issue?

    • 201.1
      Teresa says:

      From what I understand, in regards to meat, it’s the fat content, not the ph level.

      • Edwin says:

        From what I understand,the fat in the meat can protect spores. At least partly this would be because they exclude water (hydrophobic) and thus wouldn’t be affected by the pH unless it was far more acidic than you’ll get with citirc acid. (btw, this water exclusion is essentially the reason why microwaving meat won’t protect you either).

  2. 202

    […] with boiling-water canning, especially when they’re not even measured amounts (see this article for more information). I know that many people have canned this way for years, but in my opinion, […]

    • 202.1
      Jamie Ellis says:

      My great grandmother water bath canned all her stuff she didn’t have a pressure cooker and we ate everything she made. So I got her recipes and I follow them to the letter I have never had anything go bad or make anyone sick.

      • Marisa says:

        Food science has come a long way since your grandmother’s time. I would suggest updating your practices.

  3. 203
    Joan Polignone says:


    I would like to pressure can homemade sauce no meat and no garlic and the ingredients I use are:

    2 cans Pastene crushed tomatoes
    1 can Puree
    3 small cans of Paste
    1 Medium chopped onion
    1/2 cup of oil
    salt & pepper

    cook approximately four hours adding water occasional …….

    I need to know now if I can pressure cook this safely?


    Joan Polignone

    • 203.1
      Marisa says:

      Joan, I just can’t answer these kinds of questions. I’d suggest you look at the information about canning spaghetti sauce on the National Center for Home Food Preservation.

    • 203.2
      Carolyn says:


      I would suggest that you contact your County Extension office for research-based information regarding this topic. They will be able to provide you with scientific, research based information so you can preserve food safely.

  4. 204
    John says:

    Hi Marisa. Going back to Eileen’s question from September, could you just add citric acid to your favorite sauce and measure the PH level until you get below 4.5 and then can in a water bath? Thanks so much.

    • 204.1
      Marisa says:

      It’s not a recommended technique, but if you were willing to live a bit dangerously, you could. You’d probably want it to measure closer to 4.2 or 4.3, just to give yourself a slightly larger margin of error. And if the sauce contained meat, it would not be advised, no matter how low a pH you were able to achieve in the surround sauce.

  5. 205
    Andy says:

    Too bad when the family recipe originated from Italy a couple hundred years ago…adding a bunch of red wine, citrus or lemon juice is not desirable.
    Does the pH requirement stay the same even if you add meat? And I assume the added meat would also lower the acidic value so you’d have to make even more adjustments to get that back up to 4.5. Am I correct?

    • 205.1
      Marisa says:

      It is not advised to process sauce containing any kind of meat in a boiling water bath canner. For that, you MUST use a pressure canner.

      • Barbara says:

        I just processed sauce and meat in a boiling water bath canner not knowing this should not be done this way, can I reopen the jars to correct this error. I just made 30 jars of plain sauce and 30 jars of sauce with meatballs, the meatballs were cooked in the sauce before processing OMG they are Christmas gifts. Please help

        • Marisa says:

          Unless you have a pressure canner, everything needs to go into the refrigerator as soon as it is cool. There’s no way to make low acid sauces shelf stable without a pressure canner.

  6. 206
    Hat says:

    There are two wonderful tomato pasta sauce recipes created with canning in mind in the better homes and gardens’ canning magazine from this summer. Both require the tablespoon per pint of lemon, and are a bit on the tart side, but have some lovely flavors of basil and roasted garlic, and are just waiting for added cheese or meat when heated and served. I sure hope they were tested because I have 30 or more pints heading out the door this Christmas!

  7. 207
    Kimberly says:

    So not for canning, but What about for short term storage? 2-3 days. And for freezing.

  8. 208
    crystal says:

    My husband cans his sauce and it turns out fine. But of course he makes huge batches, uses red wine and cooks it for what seems to be forever! I can’t say what his secret is because I’m not allowed in the kitchen, and I’m not allowed to touch the sauce…That’s what I get for marrying an Italian.

  9. 209
    Alexander says:

    Hi, and Greetings from Germany. I know, it is not directly topic, but as meat was mentioned several times, I would like to add that they are really a lot of different sausages and meat stew recipies around here that are usually canned during home slaughtering at approx 72 °C (160 °F), this being done as long as my gramma can recall. As far as I know, there are no Botulism problems with that, but of course nobody would eat something that was visibly under pressure when opened, or the content of a bloated tin can. Sorry if I missed the subject completely – Alex

    • 209.1
      Marisa says:

      There is actually a great deal of trouble with that. Meat is low in acid and botulism spores require temperatures of 240F to be killed. There is no safe way to process meat in jars without a pressure canner.

  10. 210
    Nikki says:

    Hi I am just wondering whether once the batch of sauce (does contain lots of white wine vinegar, tomatoes and has been preserved properly) has been refridgerated can it then be stored elsewhere or does it need to be pressure canned/heat treated again/ remain in the fridge or freezer until consumed?
    I wasnt sure at the time of making it and didnt want it to spoil so i put it into the jars and into the fridge, its keeping well but it would be better to have my fridge space back!
    Any hints you may have are greatly appreciated, even for next time i will remember to just heat treat and then store not in the fridge perhaps.
    Thanks in advance 🙂

    • 210.1
      Marisa says:

      You made the sauce, canned it, and then refrigerated it? If the sauce was high enough in acid for boiling water bath processing, and the jars sealed properly, there’s no reason why you can’t take the jars out of the fridge and put them in the pantry. More information about canning tomatoes can be found here:

  11. 211
    Stephanie says:

    I have a similar issue. I make a lot of sauces that I’d like to make in larger quantities and can for my big family. (Alfredo sauces, vegetable sauces, Asian brown sugar and soy sauce sauces, etc). Csn I water bath can these, or pressure can them? How long would I need to?

  12. 212
    CrabbeNebulae says:

    It’s simpler and tastier to just make a nice thick tomato sauce (tomatoes only) and add one generous tablespoon of lemon juice to each quart jar and water bath can it. Then, make your spaghetti sauce from that, fresh, when you need it. Tastes much better. Water bath canning spaghetti or pasta sauce, or any other sauce using tomatoes WITH A MULTITUDE OF OTHER INGREDIENTS, and trying to manipulate the Ph is not safe. Pressure canning spaghetti or pasta sauce, or any other sauce using tomatoes WITH A MULTITUDE OF OTHER INGREDIENTS, while safe, changes the flavor. I’ve found it best to simply make plain tomato sauce and use that in the family recipe when you need it instead of trying to can the family recipe. Keep it simple people, and keep your awesome family recipes intact and awesome.

    • 212.1
      Marisa says:

      You actually need two tablespoons of lemon juice per quart of product.

      • CrabbeNebulae says:

        You are right… my bad. I say “generous” tablespoon because I slosh it over a lot. But, two measured tablespoons is correct. Sorry.


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