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

  1. 151
    Kate McCracken says:

    hi again I would really love an answer to my question, waiting with “baited breath!” #145 above

    Kate MCCracken says:
    August 15, 2013 at 4:41 pm
    Hi Marisa i bought your book and i love it! i made the Tomato Jam, but am now a little concerned about the acidity after reading this long post. is it okay because of the lime juice? Also i cooked it down for about 3 hours, would the lime juice have evaporated along with some of the moisture? i used fresh juice in the first batch, and bottled in the second. this is one of the most delicious recipes i have ever made with our heirloom tomatoes and would hate to dump it! any advice would be appreciated!
    Kate

    • 151.1
      Marisa says:

      The lime juice elevates the acidity and makes this recipe safe for boiling water bath canning. What’s more, there are no ingredients added to the tomato jam that lower its acidity and acid levels don’t decrease radically due to cooking. Yes, you’re evaporating out the moisture, but the acid remains.

    • 151.2
      Anne Long says:

      You can ,can your homemade sauce, minus meat, that’s only done is a pressure canner, if you raise the acidity level. You do this by adding 1 teasp of Lemon or Lime juice to each pint, or 2 teasp. to each quart.

  2. 152
    Susan Oliver says:

    Hi –

    in regards to the pH – pH scale runs from 1 to 14. Low pH is acidic, which is below 7. pH 7 is considered neutral.
    pH greater than 7 is alkaline or basic.

    So, your statement: ” When you make spaghetti sauce, one typically adds a slew of ingredients that, while delicious, lower the acid to seriously unsafe levels.” need to read:

    When you make spaghetti sauce, one typically adds a slew of ingredients that, while delicious, RAISES the pH seriously unsafe levels.

    happy canning!

    • 152.1
      Marisa says:

      Susan, we’re actually both right. When you lower the acid levels, you’re also raising the pH level. It can be said both ways.

    • 152.2
      Doctor says:

      Susan, she said absolutely nothing wrong. lowering the acid level = lowering the acidity = raising the pH. Acidity is based on protons, mainly a free hydrogen ion. When you lower the amount of free hydrogen you lower the acid level (thus raising the pH)

      • Emme says:

        Hi again, So I ventured into the canning world and bought my first Bernardine Starter Kit! Now I am of Italian heritage and I remember all of my relatives lining up their tomatoes down the driveways and garages every September but alas I was too young to help or remember. All of the aunts and my grandmother got together and made a weekend of it. I don’t remember them including garlic, but I do remember eating canned tomatoes as the base for the sugo (sauce) all winter long. They put basil leave in there. Is this safe? I want to do the traditional way of adding salt, tomatoes, basil, but would I also need to put in lemon juice or vinegar to make the pH level safe?

        I also have some Serrano peppers, ONE Ghost pepper and 5 habanero and wanted to make a killer (not botulism!) hot sauce. I have learned from reading up on canning and safety that I sadly cannot make an infused hot pepper olive oil and we would not use it quick enough in our family to even justify making it for the refrigerator. I can’t find a recipe for this and I really only want to make one small jar that came with the canning kit.

        Do you have any suggestions on the hot pepper sauce? Also, since you’ve been doing this for quite a while and know what you can adjust and cannot, are there any suggestions you can send this way to a newbie? Thanks, and your site is fantastic!

      • Emme says:

        Just wanted to come back here to add that I found the Ball Tomato-basil-garlic recipe and I think I’m going to use that one. It looks most like the ones I grew up on. :)

    • 152.3
      neal says:

      Is it possible to test the ph of a sauce at home?

  3. 153
    Jill says:

    I am getting ready to make 2 boxes of tomato sauce with fresh garlic, basil, olive oil and came across your article about adding lemon juice. My question is …Wouldn’t all that lemon juice dramatically change the taste of the sauce as it would be so acidic? I don’t have a water bath so will probably have to freeze my sauce. I am a retired chef and am very curious however about the taste of the sauce after adding lemon juice. Also how much do you add to 1 quart 1 pint…or a half pint? Thank you in advance for a response. Jill

    • 153.1
      Marisa says:

      Jill, in order to make the sauce safe for boiling water bath canning, you must add either lemon juice or citric acid. It does make the sauce marginally more tart, but it doesn’t alter it that vastly. But it’s the only way to make it safely shelf stable, so we do what we must. More about lemon juice amounts can be found at the National Center for Home Food Preservation. If your sauce is entirely plain, you add two tablespoons per quart (or one tablespoon per pint). For more doctored sauces, you’ll need more. Here’s my basic marinara sauce.

  4. 154

    […] you can’t can sauce in boiling water (something to do with pH and botulism, read this article for more info) so we had to pressure can it. Instead of buying it on sale at Bed Bath & Beyond […]

    • 154.1
      Laurel says:

      I would never recommend a water bath canning method for any tomato product, ever. Your grandma and the elderly lady across the street will tell you that “she’s done it her whole life” but now that we’re more knowledgeable about food safety we understand the importance of doing it safer. If you don’t have a pressure canner, please consider freezing your sauce.

      • Marisa says:

        Laurel, as long as you acidify your tomatoes and follow a tested recipe, they are safe for boiling water bath canning.

        • Molly says:

          I use pH strips to measure the pH of all the recipes that I can in a water bath. Its comforting (for a sciency type like myself) to KNOW that the pH is less than 4.5.

  5. 155
    Sandy says:

    I’ve read several sites that say using Olive Oil in sauce for jarring is dangerous, including Bernardin’s (Canadian maker of canning supplies) http://www.bernardin.ca/pages/recipe_page/51.php?pid=185

    However I found a recipe on Ball’s Freshpreserving.com (http://www.freshpreserving.com/recipe.aspx?r=45) which calls for Olive Oil, so I’m a bit confused.

  6. 156
    Vicki says:

    I am getting ready to can my salsa. it has black and green olives plus all the peppers etc.. That you’d normally find. I also load it up with vinegar, lime juice and lemon juice and salt. I also pressure can for 20min. I live at 3500 ft. After reading this article now I’m nervous that I should freeze my salsa or should I just put an extra tablespoon of lemon juice in each jar?

  7. 157
    Melissa says:

    I water-canned spaghetti sauce and Mexican-style stewed tomatoes about 3-4 weeks ago but just read this article warning about acidity levels today. I used Roma tomatoes in both. I boiled both for about 30 minutes before putting them in jars and boiling water bath for 40 minutes. The spaghetti sauce only had dried spices but the stewed tomatoes included celery.

    Would it work to un-jar the sauces and re-can, adding the lemon juice or should I throw it all away to be safe?

  8. 158
    Eileen says:

    I just finished processing a batch of tomatoes and realized that I *completely* forgot to add any lemon juice!!! Can I pop the seals, add the acid, and reprocess? Or do I need to throw all this tomato sauce in the freezer?

    • 158.1
      Marisa says:

      If the tomatoes are still hot, you could open the jars, add lemon juice, apply new lids and reprocess. Just know that the tomatoes are going to be really soft. If they’re no longer hot, I’d suggest freezing them.

  9. 159
    Maggie says:

    Hello. I plan on making a chicken broth based soup with a pepper, chicken, and pre-canned fire roasted tomatoes. Can I use a pressure canner to put up?

    Thank you!

  10. 160
    Julie says:

    I’m new to canning. I would like to can my mothers Spagetti Sauce Recipe. Her recipe that I have is from canned tomato sauce and what not….and no fresh tomatoes. How can I go about canning this.
    Do I have to add anything special to it? Any advice would help.

    • 160.1
      Marisa says:

      Julie, did you read this post? You can’t just can your own recipe. You can only can a recipe that’s been tested for boiling water bath canning.

      • Tom Braak says:

        I have not canned in the past 20+ years, and was recently given a pressure cooker by a fellow missionary. Tomatoes are seasonal, and I missed the season. Would like to find a recipe for spaghetti and pizza sauce using canned tomato sauce. Where might I look? I’ve been trying this morning to do find one and can’t. No libraries/ bookstores.

        I live in rural Haiti. We have a solar-powered chest freezer and find we need to make room for other things, so want to can whatever is possible.

        Thanks for any suggestions – would pressure cook it as would use hamburger and sausage (both made from fresh meat sold in the outdoor market!).

  11. 161

    […] on how to can tomato sauce, we suggest that you visit the Ball Canning website here.  Here is another interesting link about canning tomato sauce which suggests that the pressure cooker method b…of any homemade tomato sauce.  Alternately, freezing homemade tomato sauce may be another option […]

  12. 162
    Barb says:

    I love the convenience of having sauce all made both for spaghetti and pizza, I can tons of other stuff too so I use a pressure canner and follow the instuctions from the USDA home canning guide 3, the only thing I change is we don’t like green peppers in the sauce so I omit them. This is a basic sauce that can be added to when opened with whatever you want. Usually I add more spices, and wine. “Putting food by” also has a basic recipe that I have used many times, it is almost exactly like the USDA one. So if you really want Tomato sauce a pressure canner is the only way to go!

  13. 163
    permafrost1979 says:

    So I can’t use my own tomato sauce recipe for canning and have it be shelf stable, but can I keep it in the fridge? I use canned tomatoes which have had citric acid added to them, and I can add more citric acid or lemon juice. If I make a small batch (3 pts), could the sauce keep a few weeks on the fridge?

    • 163.1
      Marisa says:

      You can totally keep it in the fridge for a few days. For longer storage, I recommend freezing it. The presence of lemon juice or citric acid isn’t going to prevent mold when your sauce is stored in the fridge for a long period of time.

      • Laura Jo says:

        I made fresh tomato basil sauce yesterday. I have 2 pint mason jars leftover. The comments indicate that I can freeze it but do I need to get air bubbles out first? And about how long will it stay good in the freezer? Thanks!

        • Marisa says:

          You don’t have to worry much about the air bubbles if you’re freezing the sauce. That is something you need to do when you’re dealing with the boiling water bath process. Make sure to use straight sided jars and leave one full inch of headspace to account for expansion. They’ll be good for about 6 months in the freezer.

  14. 164
    Erica says:

    I didn’t spend the time reading all 200+ comments so this might be a repeat question: pressure cooker canning CAN be used when canning spaghetti sauces,correct?

    • 164.1
      Marisa says:

      Yes, you can use a pressure canner when preserving your own sauces. It is still important to follow basic recipe guidelines, though.

    • 164.2
      Maxwell says:

      Erica,

      Please don’t take this as a personal affront, it is not meant that way. I always find it interesting when someone says, ‘I haven’t read all the response, but…”, or simply bold face ask the same question that’s been answered dozens of times. Why do I find it interesting, well because in order to FIND your question and answer it, someone must read ALL of the responses, at least up to yours. So basically what that says is, I am far too important and my time far more valuable than yours to be bothered. So I will simply state what I want and you will give it to me. Please and thank you. Nice. Slam me if you all want, but I read all the responses, and have no questions as they have been answered multiple times. Please do not encourage such behavior by responding with the answer, simply state you will find it above, like everyone else. Stop the madness.

  15. 165
    Pamela says:

    Your favorite recipe spaghetti sauce is able to be canned… just in a pressure canner. (with no added acid)

  16. 166
    kavya agarwal says:

    hi , i just want to know that can i replace vinegar in tomato ketchup with lemon juice? will that create any difference in taste of the ketchup , or its shelf life? how can i attain maximum shelf life without any preservative… thank you in advance,

    • 166.1
      Marisa says:

      It’s best not to make substitutions in acid sources in recipes. I don’t know what kind of impact that switch would have on flavor and shelf life, because I’ve not tried it.

  17. 167
    Ellen says:

    I’m new to canning and would like to can a couple of my tomato-based recipes. However, I use tomato soup and spices in my spaghetti sauce, not whole tomatoes, no oil, etc. Can I still can it?

  18. 168

    […] the winter. No one, and I mean no one, complains when you open some applesauce, canned garden tomatoes or zucchini relish in […]

  19. 169
    Toni says:

    I want to make & can my homemade spaghetti sauce which consist of 1/2 chopped onion, two chopped garlic gloves, 1 – 28 oz., can tomato sauce, one – 28 oz. Can tomato puree, one – 12 oz. can tomato paste , 1/2 cup olive oil, 2 tblsp dried parsley, 1 tsp. Each of dried basil, oregano, 2 tsp. Salt and 1 tsp. Pepper. This makes a gallon of sauce. Can I can in quart jars by adding two tbsp of lemon juice to each jar and put in a water bath? Live at elevation of 6,100 ft. So was thinking of boiling for an hour. Can I do this and be safe!

  20. 170
    Jim Stone says:

    My neighbors and I, all Italian, have been canning tomato sauce FOR YEARS.
    WE DONT USE LEMON JIUCE when jarring, it’s not necessary! This article is insane.

    • 170.1
      Marisa says:

      Jim, modern tomatoes are less acidic than they used to be. Lemon juice actually is necessary for safety. More details can be found here. http://nchfp.uga.edu/how/can_03/tomato_intro.html

      And I really don’t appreciate you calling my writing insane.

    • 170.2
      Kathleen says:

      I agree!

    • 170.3
      Miriam says:

      This response is incredibly rude. The safety guidelines have changed over time as better testing methods have become available to ensure the long term safety of preserved foods. Marisa would be remiss if she advocated canning tomatoes without added lemon juice – in fact, she could be held liable if someone got sick following her advice.

      If you choose to take on the risk of canning tomato sauce without added acid, that is your choice, though not one I believe is particularly smart.

      • Maxwell says:

        Back in ‘the day’ when everybody did everything right, didn’t they only live until a ripe old age of 45-50? I don’t know about crazy and insane, but I do know that if a tsp of lemon juice might keep me from dying of botulism poisoning, by golly I am gonna add some lemon juice.

  21. 171
    John F. says:

    I’m sorry, but I cannot find the information I am looking for about my homemade pasta sauce. Everything says to use a recipe that has already been tried and tested for canning. But I want to can my own recipe for pasta sauce. I know that it will not have enough acid, and has a good amount of olive oil in it. I know that I cannot be canned using a water bath, but I don’t know how long it needs to be processed using the pressure canning method. Do you have any advice?

  22. 172
    Jasmine says:

    Ok, I’ve read a great deal of your comments and I think I have the answer to my question. However, I’m still a little unsure. My question is, Can I can my original recipes if I can using a pressure canner. I saw your responses in regards to canning the traditional way but I am interested in canning jams, and sauces that I make at home. I would appreciate any response regarding this matter. I do not want to accidentally get anyone sick.

  23. 173
    Kathleen says:

    I have been canning tomatoes for over 29 years and yes I make my own sauces and can it as well as salsa and stewed tomatoes and I do not use a pressure canner. I do use the water bath method and add a teaspoon of salt per jar. I make sure my sauces or whatever I am canning is boiling and I pack them into hot sterilized jars and process them for 45 minutes for sauce, 35 for salsa and stewed tomatoes, green tomatoes I only process for 15.
    I also can fruit, jellies as well as applesauce and apple butter the same way only difference is I add fruit fresh ( not for jams) but still in a hot water bath not a pressure canner.
    The only time I have used a pressure canner is for processing deer meat.

  24. 174
    Michele says:

    How much vinegar is necessary to safely hot water bath tomato chili sauce with green peppers, and onions?

  25. 175
    Lisa says:

    Yesterday I followed a recipe for canning a spaghetti sauce and did not do the hot water bath method. I followed the ‘using hot sterile jars, lids, etc’. and simmered my sauce for about 5 hours. I did add 2 tbls. lemon juice to each jar before adding the sauce. The jars all sealed after assembly so I felt they were safe to store. Then my hubby mentioned this article and I’m stressing. I just put them together last night so would it be safe now to unseal them and put them in freezer containers for the freezer? Would I need to heat it again first to be safe? I’m wondering what the best ‘save’ would be for it at this point. Thank you!

    • 175.1
      Marisa says:

      I’d suggest opening the jars, bringing the sauce to a boil to kill off any bacteria, and then packaging it for the freezer.

  26. 176

    […] only adjust spices/herbs for safety because of their finicky ph/acid levels. Read more about that here.) The idea sparked from thoughts of mole sauce and really great chili, which all use a bit of […]

  27. 177
    Bob says:

    My mom never used lemon juice. & she kept the mayo in the cabinet with the mustard & ketchup. We always cut the mold off the cheese though.

  28. 178
    Stephanie says:

    I understand the point of adding citric acid but have a question – I wasn’t reading my canning book recipe well and added the citric acid to the sauce before boiling with all the seasonings. Will it act the same and do its job or would you recommend I still add another half teaspoon to each jar. Thank You

    • 178.1
      Marisa says:

      The reason to add it directly to the jars is that you ensure that you’re going to get the exact right amount of acid into each portion of sauce. I might add an additional portion to just to ensure safety.

  29. 179
    Mike Fesik says:

    I have been canning tomatoes for over 25 years. I never add lemon juice. Tomatoes are already acidic. I don’t process in a canner either. All you have to do is skin the tomatoes, cup up if desired, and bring them to a rolling bowl. Ladle them into jars which have been boiled for 5 minutes and are sitting in the water. Add 1 teaspoon salt, wipe the rims, and seal with lids and rings which have been boiled for 2 minutes and sitting in the water. Turn jars upside down for 30 minutes, flip over, and check for sealing. I have never had a spoiled jar!

    • 179.1
      Marisa says:

      Mike, it doesn’t matter that you haven’t had a spoiled jar. Your technique is still outside of the recommended methods and is not safe.

  30. 180
    Carol Claire says:

    What causes tomatoes and/or sauce to rise up in the jar after processing? I have a half-inch to an inch of water in the bottom of my jars after my tomatoes have been processed. I put my tomatoes through a Squeezo and processed the sauce.

  31. 181
    Susan Hekstra says:

    Earlier this week I canned 90 pints of salsa with only 1/3 cup of vinegar per 8 cups of tomatoes, however I add more/less onions, green peppers etc (never measuring exactly). Now I fear it is not safe. This is a recipe I’ve used for years. For less worry can I reopen after having set for a week, boil again, add the acidic acid to each jar and put back in a water bath for canning?

    • 181.1
      Susan Hekstra says:

      Correction to previous comment: My recipe calls for 8 cups of tomatoes used with 1/2 cup vinegar plus onions etc.

  32. 182

    […] days or frozen in a freezer-safe container (leaving some space for expansion).  This sauce just can’t be canned with a boiling water bath process for long-term […]

  33. 183
    Kristie says:

    I just came across your posting. I have been canning my family sauce of tomatoes, garlic, s&p and basil for years. I have done a water bath boil for 20 minutes and never had a bad jar yet.
    I learned from someone who has been doing it for 40 years this way. I am stumped and nervous now.

    • 183.1
      Marisa says:

      Canning standards have changed a good deal in the last 40 years. It’s not about jars going bad in the traditional sense, it’s about ensuring that the acid levels are high enough to prevent botulism growth. Both garlic and basil are low in acid and if you put enough in the sauce, it can produce something unsafe. I’d suggest reading through the National Center for Home Food Preservation website to bring your practices up to date. http://nchfp.uga.edu/how/can3_tomato.html

  34. 184
    Lisa says:

    Marisa, I plan on processing my tomatoes safely using the water bath method, lemon juice, etc., and according to instructions, BUT… if i wanted to add some fresh garlic, basil and thyme when cooking them down before i hot pack, do you think it would still safely fall within the guidelines? No oil or vegetables…

  35. 185
    Joanne says:

    I don’t get it. I, my mother-in-law, grandmother, daughter-in-law and many other relatives and friends have been canning everything, especially tomato sauce, for ever 35 years now and have never had a problem. I use a water bath canner too.

  36. 186
    MissCurious says:

    Would Vinegar or Lime juice work if you don’t have Lemon juice?

    • 186.1
      Marisa says:

      You can use lime juice, but vinegar isn’t not an appropriate swap. It doesn’t have the same acid concentration as lemon or lime juice.

  37. 187
    Chloe says:

    I was wanting to can homemade spaghetti sauce, will I need to add lime/lemon to my recipe if I am going to use the pressure canning method?

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