Canning 101: Is It Safe to Can Products That Contain Some Oil?

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Earlier this week, someone asked a question on the Food in Jars Facebook page about canning giardiniera. It’s a spicy mixed pickled that frequently includes a bit of olive oil. I directed that person to a recipe from a trusted source and she wrote back, questioning the safety of the recipe because of the inclusion of oil.

It was a good question. Lots of people have been told that canning with oil is dangerous and in a sense, it is true. Canning a product that is packed only in oil in a boiling water bath canner is a definite no-no. However, if you’re making a pickle from a tested, trusted recipe that has plenty of acid and it includes a small amount of oil, it is okay.

While I’ve not made the giardiniera that I linked to (though it looks quite good!), I have made a batch of roasted and marinated peppers, following a recipe similar to the ones that Kaela, Shae and Julia posted (they are the jars pictured on the right of the image up top). They turned out just fine. Truly, the only thing you have to worry about when working with recipes that contain small amounts of oil is doing a good job of wiping the jar rims, so that no oil residue is left behind. A small dab of white vinegar on your cloth helps.

One more canning fear put to rest!

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48 Responses to Canning 101: Is It Safe to Can Products That Contain Some Oil?

  1. 1
    Shesten says:

    Thanks for answering that! I’ve been wondering a lot about that lately. Very timely for me!

  2. 2
    Leslie says:

    I didn’t know I needed to worry about oil, NOW I’m concerned – ha, ha. I make a roasted tomato garlic jam that contains olive oil. The tomatoes and garlic are slow roasted in the oven, drizzled with olive oil. When I put them in the pot on the stove, I do remove them from the oven dish with a slotted spoon to remove excess oil. From your description, it sounds like it is safe. The recipe makes 3 – 4 half pints, which I water bath. But we love it so much, it hasn’t stayed on the shelf longer than 60 days.

  3. 3
    Robin says:

    Thanks for this post. I’ve been wondering about that for a long time. Is a little butter in the recipe safe, too?

  4. 4
    Zelda says:

    The problem is, oil floats to the top, creating an anaerobic environment, exactly what botulism needs. Yes, if the food is properly acidified it is safe, but there is no way of accurately testing for acidity in a home kitchen. It’s always better across the board to avoid using fats in home canning OR to use a professionally tested recipe that’s been proven to be safe.

    • 4.1
      joanie says:

      Oil floating to the top does not cause an anaerobic environment!
      The process of canning (anything) creates a anaerobic environment.

      I can Bacon, the fattiest meat around.
      It’s not the fat that makes meats dangerous, it’s improper techniques such as time and temp and hygiene that creates the risk.

  5. 5
    Justin says:

    I actually had the same concern with a roasted red pepper recipe that I’ve used two years running now (probably the same one above except I grabbed it from Rurally Screwed). The recipe is essentially a pickle (lemon juice and/or vinegar) but it has quite a bit of oil in it so they feel more liked they’re canned in a vinaigrette. I’ve had no problems thus far with the actual canning process or spoilage. However, I have noticed that they go rancid very easily (i.e. the oil gets that nasty off-flavor). I imagine the heating process of the BWB breaks-down the oil some to begin with and then my pantry tends to be warm, which doesn’t help. Last year, I ended-up tossing the last jar because of oil rancidity. This year’s batch is already starting down that road. I may ditch the oil next year altogether in favor of a longer shelf life.

    I also use a couple tablespoons of oil to saute the veggies for my marinara sauce (which I usually pressure-can) and I’ve had no problems whatsoever there. I think the quantity is small enough and with the pressure canning, I feel I have a little extra insurance.

    The only other experience I’ve had with fat is when pressure-canning chicken stock. Unless you have the time to let it sit overnight in the fridge to solidify, some chicken fat inevitably ends-up in the jar. After canning, the fat floats to the top and sits there and can also go rancid if the jar isn’t kept cool. Generally speaking, though, I’ve found the product to be fine when I opened it–even stock opened in late summer that was made from the Thanksgiving turkey.

  6. 6
    Ryan says:

    Could you still preserve certain foods in olive oil, without going through the canning process, and still be safe? Would it need to be stored only in the fridge? I’ve thought about preserving my own roasted red peppers, sun-dried tomatoes and duck confit like that, but now I’m not so sure.

  7. 7

    You can also choose a variation of Giardiniera that doesn’t include oil. Here is mine: http://theprudenthomemaker.com/giardiniera.aspx

    I’ve really wanted to do sun-dried tomatoes in oil, but everything I’ve read so far says to just dry them, and then pack them in olive oil in the fridge a day or two before using them. Of course, even just storing the dried tomatoes that long is a bit impossible to me; they’re like candy and I just end up eating them!

  8. 8

    I would like to suggest that you include reference to university Extension resources with USDA-tested recipes. Interestingly, when you use Eugenia Bone as your “trusted source for safe recipes” it was Colorado State University Extension that helped guide her in the first place. A very good link for “trusted recipes” is the University of Georgia’s National Center for Home Food Preservation site at http://www.uga.edu/nchfp because in addition to USDA-tested recipes, it has altitude adjustment processing times which is very important for those not living at sea level. Also, for this reason, please add to your cookbook list So Easy to Preserve, produced by Univ of Georgia Extension. Thank you.

  9. 9
    Kat says:

    Mary: When I first started reading this blog, Marisa had a giveaway for So Easy to Preserve. She went on and on about what a great resource it is. Well, I had the awesome thrill of winning the book and I have to say she was absolutely correct.
    I’m thinking the reason it doesn’t show on the Amazon book sidebar is that the book isn’t available new through Amazon–rather you must go to the Extension’s website to order it. I do see that Amazon lists two sellers of used copies, but maybe it’s too variable for inclusion…

  10. 10
    RM says:

    My experience with canning Giardinera with a small amount of oil was that some oil seeped out along with air bubbles during the boiling water bath and the jars ended up with an oily coat the required lots of wiping oi get off. Probably didn’t allow quite enough headspace.

  11. 11
    Michelle W. says:

    It never occurred to me that canning with oil might be dangerous! I’d never heard such a thing. Two years ago I canned some gardiniere veggies, but the recipe didn’t call for oil. However, that same year I canned some antipasto. The recipe was beautiful, and just what my husband would love for evening snacks. The ingredients were canned wholly in olive oil. The recipe called for an extended water bath period. Two years later, the antipasto is still quite tasty!

    • 11.1
      Valarie says:

      This is my third year canning Italian Style Green Tomatoes in Olive Oil. The tomatoes “dry” with kosher salt overnight, squeezed dry, then they sit in a white vinegar bath for several hours (overnight), drained. Packed in jars with a good olive oil, then a hot water bath for about 15 minutes. I’ve never had any problem with them. Everyone loves them – no one gets sick. (Perhaps tomatoes are acid, then the salt, and then the vinegar – so perhaps it’s weighed out by all those acids)

      My Grandmother had been doing this since she was a young girl in Italy at the turn of the century (1900). Jars of green tomatoes in olive oil were stored in her basement for months. They probably could have been there longer, only everyone wanted to eat them.

      My pickled Jalapeno recipe calls for some olive oil too. They turn out terrific – the olive oil makes such a difference in the pickling process, adds a great flavor.

      So this is the first I have heard of this! So for over 100 years my family has been doing this – Now I’m a bit nervous! Who knew?!?!

      • Marisa says:

        Valarie, the hard truth of it is that we know a lot more about food safety now than we did 100 years ago, so practices that were once common are no longer advisable. The process you describe for your tomatoes is most certainly not recommended by the USDA. However, it’s still a technique that’s used in Italy. It’s a choice that is up to you.

  12. 12
    Marie says:

    Ah, thanks for this! I was a little concerned about an onion jam I made this summer, even though the recipe came from a Better Homes publication.
    It was so good, it didn’t hang around long enough for me to worry much….

  13. 13
    EB says:

    It had never occurred to me that this would be bad. I’ve always eaten canned tonnato that was in olive oil and herbs! Good to know I should watch out!

  14. 14

    Thank you, I had wondered about that too. I have canned tomato sauce with olive oil. Everything bubbled over and leaked out but still sealed! I have six kids…I can’t always make it to the stove in time!

    I also hot packed peppers fried in oil to which I also added a salt/vinegar brine. There seemed to be no problem, but, I always wondered if there was a danger.

    AND I also did this in reused Smuckers natural peanut butter jars with the original lids. My mother was horrified, but when I demonstrated that the only one in the house who could open the jar was my super-fingers-plumber husband, she just grunted.

    • 14.1
      Stephanie says:

      Marie, I looked at that same onion jam recipe! I was worried too – the recipe has butter and oil. I think I’ll just pressure can it to be safe.

      Jessica, a tight seal isn’t necessarily an indicator of safety. Reusing peanut butter jars for water-bath canning is incredibly unsafe, you should throw that food away. It’s not worth the risk.

    • 14.2
      Eisenhardt says:

      Jessica, I had the same question. I have canned tomato sauce with olive oil for the last five years never realizing the possible danger. Marisa, I would like to ask the same question if it is safe? I make very large batches of sauce in 20 qt pots or larger with approx. 1/2 cup of extra virgin olive oil. Thank you!

  15. 15
    Barbara says:

    I have a great Tex-Mex chili gravy recipe I’d love to can. It stays thick and doesn’t separate, but could it be canned? I will share the recipe if you need me to.

  16. 16
    srkshazu says:

    Found you through Twitter (thank you, Twitter!) and it seems like perfect timing.
    What a fantastic looking cookbook! Must get a hold of a copy and make this pork.
    Thanks for the introduction to Virgina Willis.

  17. 17
    Brian says:

    Thanks for clearing that up! Great information to have. :-)

  18. 18

    Great info!!!! I’m Italian, so oil is in everything!!! Thanks!

  19. 19
    Paige says:

    This summer I pressure canned a tomato soup recipe that contains butter. A few weeks later, I read that canning with butter is dangerous, so I stashed all 10 quarts in the freezer. I’m still too nervous to open them, but reluctant to throw out all the work and time I put into them. Considering that they were pressure canned, then frozen a couple weeks later, I want to think they are ok, but remain wary.

    • 19.1
      Lucy says:

      That tomato soup and many of the other posters recipes are really risky. They need to be thrown out. Do not open sealed jars of things as you risk getting botulism from just opening them.
      Pressure canning will not make things with oil safe ! It still is an anerobic condition , which is how botulism grows.
      Please, get yourself some current safe books like the Ball Blue Book and So Easy to Preserve. If you even trust any of the Better Homes, etc. they often have very dangerous recipes.
      I teach food preservation and food safety as a profession. I work at a local University Extension Office.

      • ML says:

        The Ball Canning book includes a spaghetti sauce that has olive oil in it that requires a water bath of 35 minutes. I would think that it would be safe. There is the addition of bottled lemon juice to each jar to increase the acidity. Hope this helps answer the oil question.

  20. 20

    “roasted tomato garlic jam that contains olive oil”…”essentially a pickle (lemon juice and/or vinegar) but it has quite a bit of oil in it”… “It never occurred to me that canning with oil might be dangerous!”… “onion jam”…”canned tomato sauce with olive oil…hot packed peppers fried in oil…”…”Great info!!!! I’m Italian, so oil is in everything!!! Thanks!”
    #6-Ryan: NO! you’re creating the perfect home for Botulism! Freeze those things!
    Onion jam should be refrigerated or frozen. It’s suitability for any type of canning is in question not because of acidity or fat, but because of density.

    Marisa, I hope you come back and revisit this post! Obviously you need to define “a small amount of oil” in measurement terms. The above comments are a canning instructor’s nightmare and an accident waiting to happen.

    • 20.1
      marisa says:

      Rebecca, I’m definitely planning on returning to this topic. Just haven’t had the time in the last week. Thanks for the reminder!

  21. 21
    Valeria Camargo says:

    I have been canning eggplant caponata (diced eggplant, chopped yellow bell pepper, garlic, onion, white raisins roast in oven till tender, salt), a delicious antepasto. I fill the jars with a mixture of canola or corn oil and vinegar. It lasts for at least 6 months in the pantry. After opening it, or if you decide not to can it, it keeps in the fridge for 3 to 4 months, if always covered with oil.

  22. 22
    Ellen says:

    If you Google what makes oil and fat go rancid you will find out that heat is a large factor in breaking fats down as is light and most importantly oxygen in both air form and water form( the molecule water can be broken into oxygen and hydrogen). In stability, the following fats are as follows: polyunsaturated fats are the worst in terms of stability of molecule then monounsaturated and finally saturated being the longest shelf life. Fats should always be stored in chilled conditions to make them last the longest. Rancid fat is not good for you but is not going to kill you tomorrow if you eat some. Accumulatively it is bad for you and it can deplete your system of fat soluble vitamins and is hard on your body for a number of reasons as many unhealthy chemicals are created in the break down (degrading) of fats. You CAN can meats with pressure cooking which of course will have ( some) fat in the flesh. They just recommend you use lean cuts to can to cut down on the amount of fat that can become rancid and be ingested. If you have to sauté something use saturated fat at a low temp like not over 350 degrees F in coconut oil butter or lard before canning. Which will not break down as easily with the heat of canning and frying and remove as much of the oil before canning as you can and then store the product in cool or cold storage in the dark. Also don’t store them for 2 years. make sure you use it up quickly. Remember that canned products are an anaerobic environment. Adding oil or fat is not going to make it more anaerobic. Canning is the process of driving the ” mechanical” air out of the jar with heat and “pressure canning” does an even better job of it with more heat and more pressure. The idea is that the heat kills both bacterium and fungus spores( mold and botulimun clostridium” in pressure canning. However oils and fats are fatty acid-hydrocarbon chains (lipids) and UV light and oxygen can cause the molecules to break apart. Also the air you drove out in processing is not the only oxygen present. Meat has the ability to store some oxygen in its tisue and water in the liquid in the container is a second source of oxygen that can be stolen from to break down fats and cause rancidity. Water is pretty stable as molecular bonds go but an unstable fat molecule can steel from it especially if exposed to heat or UV radiation. So, the more stable fat you use, and the cooler and darker the environment, the better for shelf stability. Happy canning. Less fat, is better than more, in canning. You can always add fresh oil when you get ready to eat your canned product. By the way, even cake mix and flour can become rancid. Buy flour in small amounts and check the packaging date to get as fresh as you can. Grain has fat in the Germ and the healthiness plummets when that goes rancid. http://www.naturalproductsinsider.com/articles/2009/08/understanding-rancidity-of-nutritional-lipids.aspx
    has a good easy to understand page that explains fat breakdown. Hope this helps to stop the panic on this page :).
    I love science.

  23. 23
    Ellen says:

    Sorry for the book length entry.. .

  24. 24
    Terri says:

    I have a barbeque sauce recipe that has butter in it. Since it also has vinegar it I assumed it would be safe for canning. Agree?

    • 24.1
      Marisa says:

      Terri, it depends on how much butter is in your recipe. If it’s just a pat, it should be okay, but if it’s a significant amount, probably not. Butter is different from oil because it contains milk solids. So it becomes something that can lower acidity and render a product unsafe.

    • 24.2
      Lucy says:

      No, not at all ! It is unsafe unless it was safety tested in a lab by a reputable University or Ball.
      The butter can allow botulism to survive. You should toss the jars, do not open or you risk getting potential botulism from just opening them.

  25. 25
    kathleen morgan says:

    Just got some chopped garlic in to make about 100 jars of garlic dills. The garlic is stored in oil! Can I still use it? My guess is yes as the amount of garlic will be minimal and the jars will be water bathed. What do you think? Many thanks.

  26. 26
    Jean Bledsoe says:

    If I find a Giardiniera recipe that calls for oil, can I simply omit it?

  27. 27
    Ann Milster says:

    Hi, I made a wonderful hot(whole) jalapeno pickle recipe last year that called for 2 tbsp of olive oil, along with 3 cups of cider vinegar, garlic and spices. I just finished making a new batch for this coming year. Over time, the liquid has disappeared at the top of the still well sealed jars. I wouldn’t worry if they didn’t contain oil, but now after reading everything about botulism, I am concerned. Some of the peppers are poking up into the ‘air space’ through the little layer of oil. As I said, they are still tightly sealed. Are they safe to eat? Not wanting to kill off my family and friends!!!!

    • 27.1
      Ann Milster says:

      I forgot to say that the two remaining jars from last year are the ones I am asking about. These pickles are processed in a boiling water bath for 10 minutes and haven’t lost liquid in the process…it’s just over the year (I suspect the peppers may have absorbed the liquid)

  28. 28
    PrepperDaddy says:

    Ok…so my question/comment, since we are speaking of oil. I buy my coconut oil, from TT on the internet in 5 gallon buckets. I then melt the oil over low eat in my stainless steel BAP. While the oil is melting I place 1/2 gallon jars in the oven and heat to 250 degrees. Oil is ready – jars are ready – I fill jars and cap with lids and band. When the jar cools the lid seals and the jars are ready for long term storage….this is not really “canning” I am just trying to get a good seal on the jar…and it does work. Any chance of botulism in the coconut oil that I store like this?

  29. 29
    Eunice says:

    Is this why many recipes for chicken stock advise to skim off the fat?

  30. 30
    Liz says:

    Question – so I have a water-bath canned artichoke recipe from what look like a reliable source (Eugenia Bone’s book) that calls for 3 cups acid (vinegar + lemon) and 1 cup olive oil. I want to omit the oil entirely – would the proper thing to do be to replace that liquid with more acid? Or is water an OK substitute? And a more general question – based on what you’re saying here, that 1 cup olive oil seems like A LOT – the recipe is only for 4 pints, so I’m sure it’ll float in a layer above the vegetables – so how is this not a botulism risk?

    Thank you for any input … love your blog, it is such a valuable resource.

    • 30.1
      Marisa says:

      To answer your second question first, the presence of all the acid makes the oil okay. Oil is more of a rancidity risk than a botulism one. If you’re omitting the oil, I’d use more vinegar in its place. However, knowing Eugenia’s work, I am more than certain that the recipe is safe as written. She’s meticulous.

  31. 31
  32. 32
    Cris says:

    Hi! I need help. I have some
    Cured ground Spanish chorizo pork in the freezer I want to bottle:
    1. I want to cook and fry and bottle by pressure canning with olive oil so I’m guessing this bad? My pork has Prague powder. Does this make it safe to can on oil?
    2. Do you suggest I just can in water? Or is it ok to pressure can in vinegar?
    3. I am using a pressure cooker, I read that in should add weight to te jiggler? What should be the
    Weight? How long should it be in the pressure cooker? Or how do I tell if the pressure is good.

  33. 33
    Jordan says:

    Are there any specific quantities available for what is a “safe” amount of olive oil in a canned recipe? As previously mentioned there is a recipe in the BBB for pasta sauce called “seasoned tomato sauce” that calls for olive oil. I assume this is a safe amount.
    It calls for 1/2 cup oil in 45 lbs of fresh tomatoes. I often make batches with only about 15-20 lbs and use 1/4 cup. Is this too much? Is there a ratio of sauce to oil that can give people a better idea what is safe?

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