In general, you want your home canning to be as fat free as possible for technical reasons.
Fat, in canning, can:
- Interfere with a good seal taking effect and holding;
- Go rancid in the jar over time, whether there is a good seal or not;
- Interfere with proper and full heat penetration while you are processing the jar.
Sealing issues with canning jars caused by fat
The National Center for Home Food Preservation says,
Why is it necessary to remove as much fat from meats as possible before canning? Any fat that gets on the rim of the canning jar can prevent an airtight seal. Excess fat in jars makes it easier for the fat to climb the sides of the jar and contaminate the seal. [1] National Center for Home Food Preservation. Canning FAQ. Accessed March 2015.
Oregon State University Extension Service says,
Fat left on meat will climb up the sides of a jar during processing and may prevent sealing.” [2] Scott, Judy. Oregon State University Extension Service. Pressure cooker needed to can meat and poultry safely. News Release October 2010. Accessed March 2015.
Rancidity Issues in canning caused by fat
The National Center for Home Food Preservation says,
Remove excess fat, as it goes rancid most easily.” [3] National Center for Home Food Preservation. Blog posting January 2014. Accessed March 2015.
Heat penetration issues caused by excess fat in canning jars
The National Center for Home Food Preservation says,
…fats can protect spores from heat if they are in the product during a canning process.” [4] National Center for Home Food Preservation. Canning FAQ. Accessed March 2015 at https://nchfp.uga.edu/questions/FAQ_canning.html#33
The authors of Putting Food By say,
Fat insulates against heat just as it does against cold, and the more fat there is in a food, the slower the penetration by any heat.” [5] Hertzberg, Ruth; Greene, Janet; Vaughan, Beatrice (2010-05-25). Putting Food By: Fifth Edition (p. 48). Penguin Publishing Group. Kindle Edition.
Exceptions to the rule of thumb
That being said, as with everything, it’s not a black and white world. With any pressure canned containing meat (even the 97% lean ground beef in the jar in the photo above), a certain amount of fat is going to be in the product, no matter how lean a cut you start with, and that is fine. What is being cautioned against is an excess of fat: leaving in or adding oodles of grease to the food product.
As well, there are some “authorized” and tested recipes that require or give the option of the use of added fat in the form of an oil or actual fat.
Penn State Extension notes:
The USDA Complete Guide to Home Canning includes three recipes that have oil in the ingredient list: marinated peppers, marinated whole mushrooms, and pickled three-bean salad. Each of these recipes includes added acid ingredients (lemon juice, vinegar) as well as preparation steps to ensure adequate acidity of the vegetable. There is a small amount of oil in each recipe and sufficient amount of acid. These recipes have been scientifically research tested for safety.” [6] Penn State Extension. Caution: Don’t Can in Oil. 2 July 2012. Accessed January 2015.
When you are canning ground vension, the USDA and NCHFP call for you to add lard to it:
With venison, add one part high-quality pork fat to three or four parts venison before grinding.” [7] National Center for Home Food Preservation. Ground or Chopped Meat. Accessed July 2015.
The University of Alaska Extension calls for oil to be added to some canned fish:
For halibut, add up to 4 tablespoons of vegetable or olive oil per pint jar if you wish. The canned product will seem more moist. However, the oil will increase the caloric value of the fish.” [8] van Delden, Kari. Canning the Catch. FNH-00128 . University of Alaska Fairbanks Cooperative Extension Service. Revised January 2014. Page 3.
The above examples given are for pressure canning, but there is also oil called for in some tested recipes for water-bathing from trusted sources, such as these three from the NCHFP:
- Marinated Peppers (1 cup / 250 ml oil);
- Marinated Whole Mushrooms (2 cups / 500 ml oil) ;
- Pickled Three-Bean Salad (¼ cup / 75 ml oil)
So, generally, one of the things that makes home canning so low in fat is that it’s mostly all done low fat, for various technical reasons. But, when a tested recipe from a trusted source does call for adding fat or oil, then do so worry-free.
Oil is not a safe way to preserve food
In some traditions, such as Mediterranean, people preserve food by putting it in a jar and pouring oil over it. This is highly dangerous.
The concern about vegetables in oil and botulism remains current. The products are popular, home production is common and, according to Food Science Australia (2000), two false assumptions persist:
- That the addition of oil has a preservative effect. This is incorrect. The only function of the oil is to prevent oxidation from air in the container which can lead to discolouration of some foods. By excluding air from the surface, one is establishing anaerobic conditions which actually favour the growth of some types of bacteria. Unfortunately, C. botulinum is one of these bacteria.
- That some herbs and spices, and especially garlic, have significant anti-microbial properties. This is also incorrect. The preservative effect of these materials is slight and inconsistent as the botulism incidents in Canada and the United States prove. [9]Shelf stable acid preserved foods. New South Wales Food Authority. Australia. FI035/0811 . August 2011. Page 3. Accessed August 2017 at https://www.foodauthority.nsw.gov.au/_Documents/scienceandtechnical/shelf_stable_acid_preserved_foods.pdf
And while people in Europe will say “no one ever gets sick from doing that”, they are uninformed.
Vegetables in oil have contributed to 54% of the cases of botulism in Italy between 1992 and 1996, where approximately 40 cases per annum have been reported (Aureli et al. 1999; Squarcione et al. 1999). Other vegetable preserves have been implicated in 10% of cases. While many of the products implicated were home-prepared, a proportion was produced commercially.” [10]Barbara M. Lund and Michael W. Peck. EVALUATION OF THE RISK OF GROWTH AND TOXIN PRODUCTION BY CLOSTRIDIUM BOTULINUM IN SELECTED NEW PRODUCTS OF CONCERN. Food Safety Science Division, Institute of Food Research, Norwich Research Park, Colney, Norwich. 2000. Page 19.
References
Michael k
Hey there,
I’ve recently got into pressure canning at home and have a few questions I can’t seem to find a straight answer to. I pressure canned meatballs in a tomato sauce and there is roughly 1/3 cup of oil/fat leftover on top of the jar. The jars sealed properly but I’m wondering if they’ll be safe to eat and what their shelf life might be
I also have some chicken stock that has maybe 1/8 c of fat in it as well and have the same questions about it.
Thanks!
Jack
My big question is: if my canning bath has oil in it after I process my jars (meaning that the oil in my recipe leaked out with the air and water during the canning process), does that mean the seals are definitely compromised, since there is oil between the glass and the sealing compound? I had 1 1/4 inch of head space as per my recipe.
Healthy Canning
If you got a seal, you are probably good to go. We’ve seen that happen for instance with the USDA’s marinated mushrooms recipe which has oil in it, and the jars have got a seal, and the seal has held.
J.Bailey
Concerns about this recipe being safe to preserve using the water bath method. It also calls for oil in the recipe. We used this recipe last year without any issue (before I knew better), but after doing more research I’m wondering if this is a safe recipe to use again. I contacted the original poster, but have not received a reply back.
https://farmfreshforlife.com/canning-and-making-homemade-spaghetti-sauce/?epik=dj0yJnU9RjNpUHFfbGRxeHYxMm5XeTBRd1dSVVdfTDNsQ0NXTk4mbj01eEVEWGNuWmpQQkFzZWNrbWswVzBBJm09MyZ0PUFBQUFBRjFyQlpF
Healthy Canning
IT’s probably better to disregard her take on things — she’s adding extra low-acid ingredients such as the green pepper, which is a no no.) Best just to make the original Ball recipe, which does btw call for the oil. It’s on page 33 of the most recent version of the Ball Blue Book. If you don’t want the oil in it, Bernardin has a Seasoned Tomato Sauce that is very close without the oil
JULIUS
I want to preserve meat in a tin can using oil….I need to know which oil is best for preservation and won’t change the taste of the meat. And which will give the food a longer shelf life?
Healthy Canning
The only reputable source we’re currently aware of that still gives trusted advice for home canning in tin cans is the University of Alaska Extension service. Here is their advice on home canning meat in actual cans.
Casey
Hi, I would like to make a jalapeno salsa using a tested recipe of 300ml lemon juice per 1kilo of jalapeno peppers and a little bit of sea salt for flavour. This mixture would then be sterilized in a water bath for 15minutes. Is it possible to add a small amount of olive oil for added flavour and texture and if so how much and how would that increase/affect sterilization times (also would this affect the headspace?)? Many thanks, Casey.
Healthy Canning
Hi Casey, where is the tested recipe from, who tested it? The reason I ask is — I’d ask your source directly about that change.
Maria
I’m looking at making the following recipe, it does call for 2 tbsp oil in the recipe and the canning times are wrong (recipe calls for 15 minutes) but I would use 45 minutes. Question – do you feel the amount of oil is negligible and I can go ahead and can this recipe? https://www.thekitchn.com/how-to-make-tomato-paste-cooking-lessons-from-the-kitchn-206853 I know the general rule of thumb is no oil in canning, but I’m starting to read more about a little bit of oil is o.k.?
Healthy Canning
Oil is fine in tested recipes that call for it, but that processing time seems WAY off base making me feel none of the recipe might be tested for heat penetration, and tomato paste is pretty dense stuff.
What about one of these two recipes instead?
https://nchfp.uga.edu/how/can_03/tomato_paste2.html
https://www.bernardin.ca/recipes/en/tomato-paste.htm
There’s also a roasted tomato paste recipe in Ball All New. 4 oz jars, 40 minutes processing.
Earl Blair
We are mixing some ingredients for canning salsa – we accidentally chose a “garlic paste” substitute for the required ingredient of garlic. Then we discovered the garlic paste contained: Garlic, non-GM canola oil,whey(milk), sodium lactate, sea salt,dextrose,glycerin, citric acid,calcium chloride,xanthan gum. We used 3.5 teaspoons of the garlic paste in making approximately 4 to 4.5 pints of salsa.
Is the small amount of canola oil and whey in the salsa (per the garlic paste) going to be a problem in our canned salsa ?
Or is the amount so small it will not cause a problem ?
Thanks for any info …
Healthy Canning
Hi Earl, those would be such trace amounts that they will be fine, provided you used a tested recipe that is fine to start with. In the future, if you are going for a modicum of convenience, you could opt for the (oil-free) minced garlic in jars.