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

September 1, 2010(updated on October 3, 2018)

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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452 responses to “Canning 101: Why You Can’t Can Your Family’s Tomato Sauce”

  1. 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

    • 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.

  2. 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 🙂

    • 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:

  3. Hi,
    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?

  4. 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.

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

  5. Hi, I have been canning for several years and every summer I make a tomato basil sauce from the Blue Ball Book. This year in just one of my batches the oil separated after the hot water bath. (The recipe calls for one TBS of olive oil.) It is possible I used a generous TBS of olive oil, but otherwise I am not sure why this happened. I was wondering if you had any insight and most of all, is this safe?

  6. My Roma plants are beginning to ripen, I am really trying to get them ripe on the vine,but I have been freezing then to make sauce later. I am asking if slightly under ripped is OK to use to can. Could I still use table ripened like vine ripe? I plan to pressure can? People are saying it’s fine if the fruit looks good. l

  7. Can you re-jar pasta sauce that is store bought? I’ve been trying to find information on this with no luck. I always end up wasting store bought pasta sauce because it doesn’t get eaten before going bad. I’m wondering if I can buy a large jar and then re-jar into the smaller ones.

    This is for times when I don’t just make my own sauce 🙂

  8. May I make a reply here? I have a recipe that my aunt and the lady from our local extension office helped me with several, several years ago. She knew that my recipe had oil in it. It makes 12-13 quarts and has 2 cups of oil in the whole recipe. I add 1 tbsp lemon juice to each jar (not important to what I am saying, but just in case someone mentions it, and yes that is the amount the lady from the NC State Extension Office told me to use). I just ran up on this website and now a couple more that all say do not use oil to can with. I’m honestly not sure why. Is the difference in the way you can your sauce? Most recipes I see call for a water bath, but I have always canned mine at 12 pounds of pressure for 10 minutes (per the instructions from our local extension office lady.) I am canned my spaghetti sauce this way for years without any trouble, and to now see that someone is saying we are not suppose to use oil has just floored me.

  9. I never canned before last week and never knew of the dangers of canning your own tomato sauce. I canned 12 jars last week and put in cool basement I did a water bath not adding any lemon juice or wine vinegar. Should I throw out the entire batch or can I take it out of the jars and freeze it or re-can it with lemon juice in each jar or is one week too long?

      • I have a similar situation, my mother in law canned my tiny tomatoes that were roasted with peppers, onions, garlic and olive oil. She cleaned the jars in the dishwasher and the sanitize setting. She boiled them for 35 minutes. All the jars “popped”. They have been stored in the pantry. It’s been warm for the couple of weeks they have been stored, up to 80 degrees in the house. If there was no boiling of the jars and no lemon juice added, what should I do with them?

  10. I just made tomato sauce and salsa last night with one of the recipes on line. I boiled my my jars and put the sauces in the jar but for got to do a water bath. Is it still safe to use this boil it again and the jars and than do a water bath.

  11. I never add meat to my canning sauces, and I start with 25 lbs of fresh frozen garden grown tomatoes from our yard,I add carrots onion basil thyme marjoram oregano rosemary sage and savory 1quart of olive oil 2 cups of organic cane sugar 1 cup of lemon juice 8 bay leaves and cook it down like my grandmothers did 24 to 30 hours on low heat stirring the pot about every 3 hrs, Its a long process but it is worth it in the end the sauce is dark red almost rust coloured and has a nice sheen on top when stirred.

  12. Opinions swing like a pendulum. For generations people canned meat successfully because they had to but how many stories of food poisoning from home canning have you actually heard of. I think a lot of us would be more convinced if we heard real life stories.t he Amish can extensively because they don’t believe in using electricity

    • You don’t need electricity to can safely. And there were many instances of food poisoning in the past. The recommendations contained in this post are not opinions, they are science.

  13. My Aunt and Uncle were hospitalized 2.5 years ago with botulism. They were both in their mid 80’s and ultimately my Aunt wound up passing away. The CDC had to test everything in their kitchen to discover the cause. It turned out to be her jarred tomato sauce that she had been making and jarring annually for 60+ years. Seeing it firsthand we now know how important it is to follow food safety guidelines. My family doesn’t currently jar our sauce anymore, but have been working towards figuring out how to do it safely so we can keep the tradition alive for future generations.

  14. So, I just made and water canned marinara sauce which included olive oil,carrots, 0nion, garlic, herbs, Roma tomatoes… I boiled in a water bath 45 min following a recipe on the internet yesterday and refrigerated after cooling after I found out you aren’t supposed to can sauces. What can I do if anything to re-can for gifts or at least to save for self use, such as freezing? Because it’s delicious.

    • You can’t can a sauce like that without a pressure canner. You could transfer it into freezer-safe containers and freeze it, though.

  15. Being 75, let me say that the pioneers canned everything and there was no such thing as a pressure canner. I canned green beans, tomato sauces and ketchup, pickles, corn…LOTS of things with no pressure canner. First you shouldn’t do it if you don’t know what you are doing. You should be able to tell if the item has a good seal and also if the seal breaks. It’s like saying, if you don’t wash your hands you will get sick. No, you might! What are the odds?

    • We know a lot more about food safety than the pioneers did. Additionally, many of them died of unknown illnesses. Why put yourself at risk when we have such deeper understanding of the science of food safety now. To can green beans and corn (low acid foods) without additional acid or a pressure canner is gambling with your health. Why take that risk?

  16. To be fair, the US has roughly 127 cases of botulism per year. Of that number, 15% is foodbourne. Assuming a population of 300 million, that amounts to 7 millionths of a percent. How many people are canning tomato sauce in a boiling water bath? Probably a lot. I’ve been doing it for 25 years, and my mother and grandmother before that. I can salsa the same way. I have a better chance of being struck by lightning or winning the lottery than contracting botulism. Of course anything is possible but this seems like a stretch…

  17. Hi! I’ve only canned a couple of times and the other day I used a recipe for salsa that called for store bought canned tomatoes (28oz) and 3 jalapeños, Cumin, salt, garlic powder and 4tsp lime juice. Well, I canned it in a water bath and am now seeing that maybe I should have used a “tested” recipe(?) is it safe to eat??

  18. I made a spaghetti sauce tonight and made way too much and was wondering if I could safely water bath can it if I add citric acid to it and how much citric acid should I use? I used 3 cans of canned tomato sauce, 1 can of canned tomato paste, water, 2 T minced garlic, 1/2 cup of chopped onion, dried herbs, 2 large tomatoes diced, 1 T olive oil, and 1/2 cup of red wine.

    • You cannot can an untested tomato sauce recipe. What’s more, I can never advise on the safety of a recipe for canning based on an ingredient list.

  19. I canned several quarts (24) of spaghetti sauce in the last few weeks. I did a water bath (for 35 minutes) not adding any lemon juice or vinegar. I also added extra herbs. Should I throw it all out? Or can it be saved in any way? Maybe take it out of the jars and freeze it or re-can it with lemon juice?

  20. Hi there – slightly off-topic, but you mentioned that you are in the Philadelphia area. I am in Center City Philly and looking for a good place to buy several bushels of tomatoes in late summer. Do you have any recommendations in or near the city? (If I have to drive to Lancaster County, I will, but it’s always best to ask first.)

    • Hi Chase! I’m also in Center City. I am going to send you an email with a couple of options.

  21. I put up several more jars of whole tomatoes last year than I actually needed. They were all processed according to the home preservations standards. I was wondering if I could add some (about 7 quarts) of these jars of whole tomatoes when I make my tomato sauce this year. I plan on putting up three to four boxes of fresh tomatoes for sauce. My tomato sauce and last years whole canned tomatoes contain nothing more than fresh tomatoes, canning salt, and lemon juice. For both the sauce and whole tomatoes I removed the skins. For the tomato sauce I also remove the seeds.

    • I don’t see why you don’t just keep the tomatoes as they are in the jars. They keep for several years. There’s no need to transform them if you’ll use them as-is at some point in the next year.

  22. Do you have any recommendations for a very simple sauce (canning approved) that isn’t heavy on the spices? For example, below is a simple one I found online and really enjoy but based on your article I don’t think it would be canning approved even if I followed protocol of adding the citric acid.

    14 oz can of European tomatoes
    3 Tbslp extra virgin olive oil
    1/2 tsp sea salt
    a few pinches of dried oregano
    2 or 3 leaves of fresh Italian basil

  23. Can you water bath spaghetti sauce with cooked onions and a little carrot juice in it? I heard that onions are slightly less acid than tomatoes..and add 2 T lemon juice?

  24. HI – Most recipes call for canned tomatoes and don’t seem to speak to substituting with fresh. I’m pressure canning and using meat, but wondering if I need to change anything else if I’m swapping in tomatoes from my garden? (which I have been for years!) I’d love a safe recipe that uses beef, pork and fresh tomatoes and lotttttts of herbs. Any recommendations?

  25. I plan on pressure canning this sauce. my question is, in our recipe we add chicken broth and the spaghetti season packet along with meat and other veggies and would like to use my fresh garden tomatoes. Normally we freeze the sauce but I am running out of room. Would this be safe to can and how long should it be canned?

  26. Hi! I have an old Italian recipe that’s very simple: tomatoes, olive oil, garlic, capers, red pepper flakes, white wine, basil, and salt. Can I use ph test strips to ensure proper acidity and then pressure can it? If not I guess just make plain tomato sauce and use that for when I want this phenomenal pasta sauce? Obviously the most important part is the fresh tomatoes. Truly there’s no other sauce out there like it, especially since it’s cooked WAY down to intensify the flavors!

  27. Hello, I have several jars of canned tomato sauces and stewed tomatoes that I canned last year. Upon opening, is there any way to tell if they are safe to eat? They all sealed at the time of canning

  28. I was gifted a lovely jar of home canned marinara sauce. I have no idea what process was used. Is it possible for me to put it into my pressure canner snd reprocess it just to be safe?

    • If you can’t guarantee that it was processed safely, the only truly safe thing to do is discard it.

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