How to Can Tomatoes

Canned TomatoesFor people of a self-reliant ilk (as Primal readers usually are), what better way to ensure the quality of your food than preparing it yourself? I post a lot of recipes for various meals on MDA, and I’ve urged readers to produce their own food if possible – either by hunting or gardening. There was even that sauerkraut guide last week. But until today, I haven’t tackled the age-old process of home canning.

In the past, I’ve been a bit critical of canned items, and rightfully so. The soups are often loaded with preservatives and lines and lines of unrecognizable ingredients, while canned fruit is usually soaking in a syrup bath. Canned vegetables are a great choice when fresh produce isn’t available, but you still have to check the ingredient list. Still, the convenience of canned goods can’t be beat, and all those concerns about unPrimal ingredients go out the window if you take it upon yourself to learn how to can your own food. Just as cooking at home allows you to make sure your meal is truly Primal, home canning allows you to control exactly what goes into your canned food.

You can can just about anything: fruits of all kinds, vegetables, pickled items, salsas, sauces, even meat and fish. Obviously, you’ll want to avoid the sugary jams or baked beans that are typical in home canning, but as long as you stick to already Primal foods, you’ll reap the benefits of canning (which are considerable). You can buy in bulk and never worry about things going bad. If you’re the survivalist type, you can can your own goods for the disaster of your choice – canned goods won’t go bad just because the power went out.

Probably the easiest for beginners is canned tomatoes, so that’s what I’ll talk about today. I started by gathering the necessary items:

  • Eight largish tomatoes (red and yellow, preferably homegrown or organic)
  • A dozen basil leaves
  • A bit of sea salt
  • Three 1/2 pint mason jars
  • Tall crock pot for sealing the jars
  • A rack that fit in the bottom of my crockpot
  • Smaller pot
  • Bowl for cold water

Clean your hands with soap and hot water. An absolutely sterile environment is required for good home canning.

Put the rack at the bottom of your crock pot. I didn’t have one that fit, so I had to bend and break a little-used oven rack (mini-workout!) to size. Fill your crock pot with enough water so that your jars can stand up straight and still be covered by an inch of water. Boil it. Fill your smaller pot with water, too, and get it boiling.

Wash the mason jars with soapy water and rinse, then sterilize the jars, their rings, and their tops in the boiling crock pot for at least ten minutes. Leave them in the water until you’re ready to can.

Wash your tomatoes and dunk them in the boiling water in the smaller pot for about a minute. Once the skin starts to split, dunk them in a cold water bath and peel the skin off. It should come off easily. After removing the cores and any bruised spots, sprinkle your peeled tomatoes with sea salt. Cut, dice, or leave your tomatoes whole – it’s your choice (I tried to keep them as whole as possible, but I did end up cutting a bit and smashing them down in the can).

Put your tomatoes, along with a few basil leaves (optional), into your jars. You’ll want to avoid any air bubbles, so force them down. Do a little smashing if you have to. Once they’re all in, use a wooden spoon to go along the sides and remove any lingering air bubbles. Leave about 1/2 inch of space at the top.

Using a damp, clean towel, wipe the rim of the jar clean. Put the tops on and screw them down with the ring, but not too tight – don’t strain. Place your jars in the crock pot on top of the rack (the rack allows water to flow underneath the jars); the water should be at a roiling boil.

Remove your jars after 40 minutes and place on the counter to cool. Don’t touch or move them. After about a day, you might hear a popping noise as the seal occurs. A properly sealed canned item will have a depressed indent in the lid. If you don’t have that indent, your food isn’t sealed. In that case, eat the stuff now or try again.

If canned tomatoes are properly sealed, keep them in a cool, dark place and they’ll stay for years. Enjoy!

If you truly want to get into big-time canning, buying a pressure canner is a good first step. Canning acidic items, like tomatoes (or tomato-based sauces), salsas, or fruits, can be safely done using the above method, but canning meats, fish, and other less acidic foods requires a proper pressure canner. These can be a bit pricey (around $100-120), but they’re very useful if you think you’ll be doing a lot of canning. There are also dedicated boiling canners for less money that do essentially the same thing as my makeshift crock pot-with-a-broken-oven-rack, only the rack is built in (but again, these are only good for acidic foods). Otherwise, if you’re just going to be doing the occasional canning, the Primal quick and dirty method will work just fine.

Further Reading:

How to “Primalize” Your Pantry

How to Make Your Own Jerky

Homemade Condiment Creations

TAGS:  cooking tips

About the Author

Mark Sisson is the founder of Mark’s Daily Apple, godfather to the Primal food and lifestyle movement, and the New York Times bestselling author of The Keto Reset Diet. His latest book is Keto for Life, where he discusses how he combines the keto diet with a Primal lifestyle for optimal health and longevity. Mark is the author of numerous other books as well, including The Primal Blueprint, which was credited with turbocharging the growth of the primal/paleo movement back in 2009. After spending three decades researching and educating folks on why food is the key component to achieving and maintaining optimal wellness, Mark launched Primal Kitchen, a real-food company that creates Primal/paleo, keto, and Whole30-friendly kitchen staples.

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37 thoughts on “How to Can Tomatoes”

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  1. I was just wondering yesterday about canning tomatoes (seriously, I was), so thanks for posting this! Now all I have to do is wait for summer and the generosity of friends with an overabundance of tomatoes…

  2. You need to add citric acid to tomatoes to bring their pH down low enough to be food-safe against botulism.

    1. Help!
      My tomatoes that were green,got ripe. So I made a spaghetti sauce. It was bitter!
      I added sugar to the recipe, but that did not help. What didn’t I do, or what did I need to do. . . ?

      1. I also made spagetti sauce with my green ripe tomatoes. I too, tried everything to change the flavor.
        What did you find out?

      2. my comment below was really for you. I clicked on the wrong reply I guess. We didn’t try it on green tomatoes but we put it in our Spaghetti sauce and the balsamic vinegar does work.

    2. just add a little balsamic vinegar. My husband is a chef and we made some too and the balsamic vinegar blends everything together and gives it a smooth taste.

  3. I have to admit… I laughed out loud a bit at the mental picture of Mark in his kitchen bending metal.

    Thanks for this post – I’m really enjoying the “How To”s.

  4. Okay, this is a ridiculously unprimal suggestion, but during the whole canning process, what about mixing a little blue food coloring in? Yes, it’s an unnatural, chemical, and possibly evil thing to do to a tomato. But blue tomatoes? How fun is that?! Anyone have any specific problems with food coloring? If not, I’m blueifying my tomatoes. And maybe my kraut too.

  5. Good tips – I am going to be canning and freezing a lot this year as my 1-acre garden gets planted starting on Saturday!

  6. I have just recently found this website & am LOVING it! I am making a switch from ovo/lacto vegetarian to primal (I’ve only had fish so far) and find this site informative & inspirational. I have been toying some of the recipes & when it’s perfected, look for Energy Bar III! I just canned my first veggies last fall & was wondering if pickling is “primal”? I love my beets & purple eggs… & pickled Brussel Sprouts are awesome.

  7. Welcome, Peggy.

    Pickle away!

    I look forward to hearing if and how you can perfect the Primal Energy Bar.

    Thanks for the comment and stay in touch!

  8. Ugh, I can smell the tomatoes cooking in our family kitchen. I see the slimy little blobs in the bowl of goulash and on the Swiss steak. I was the least finicky of the kids, willing to eat anything except tomatoes, which my mother loved and served at least twice a week, and forced me to eat.

  9. This blog is always up my alley. I love this blog. I use a pressure cooker, then I don’t have to worry about adding vinegar or whatever to increase the acidity. With a pressure cooker you will be able to can soups and stews, which I think process pretty well. Refer to the Ball canning guides for details–great source of info. I was a big time tomato and pepper gardener when I lived in Chico, CA. I prefer to can salsa or plain tomato sauce rather than canning whole tomatoes; it’s just a more usable product for me. I have a juicer attachment for my kitchenaide mixer and it makes a beautiful puree out of tomatoes–this way you don’t have to deal with the skin blanching stuff and you can then cook it down and condense a lot of tomatoes into 8 or so jars. (I’m talking, HUNDREDS of homegrown tomatoes all ripe at once. I had tunnels I’d crawl through in that tomato garden!) Canning is not surgery–hands clean is always good in the kitchen but if the contents of the jars are brought to 240 degrees in a pressure cooker and kept there for a long time, it’s gonna nuke anything pretty much. And the stuff that can grow in low acid foods brought only to the boiling point is going to come from the food itself, not your hands, as far as I understand it. BTW apples can be quartered (not even cored) and boiled till soft then run through the juicer, too, then cooked down and canned as applesauce. I did that as baby food for my own, about 16 years ago. She still likes my homemade apple butter. Since I’m fructose intolerent, I can’t eat apples anymore. I’m going to try growing tomatoes again this year, though, after many years–a 20′ by 5′ raised bed is being erected in my yard and seedlings are being faithfully brought out to the front porch and then carried back in each night. It’s fun but I know Oregon will never yield me what I had in Chico, in terms of tomatoes. Heck in Chico those little seedlings would be in the ground, 10 inches tall by now! My husband will probably eat them all before I get a chance to can any of them!

  10. If you start canning fresh veggies, you are headed down a slippery slope! My family would only eat home-canned green beans, not store-bought! And home canned tomatoes are vastly superior to store bought. You can also freeze tomatoes after skinning & quartering. Good for soup.

  11. Thanks for the suggestion to buy in bulk and can stuff, the thought never even occurred to me. I always associated having a garden with canning, like you had to grow it yourself in order to can it. Funny how the mind puts up walls and tells us there’s only one way to do things.

    Now I can’t wait for the farmer’s market to open here, I’ll be buying a lot more than just what I can eat each week. I had actually given up tomatoes during the winter, figuring it was better to pay twice as much for local, organic tomatoes for a few months than waste money on crappy grocery store tomatoes all year long.

    Thanks for showing us that it can be easy, canning always seemed like a daunting thing to undertake. Sometimes I make the dumbest things seem so hard when all it would take is reading the instructions…

  12. Holly,

    Green eggs are made by chickens, NOT food coloring. If you want green eggs, you need to buy the right chickens. I recall my dad eating them at a relatives place when I was a kid. They only had a couple chickens that laid green eggs so I didn’t get to try them. (I don’t think they are any different other than the color of the shell)

  13. Pressure canning – the way to go! I pressure can everything I can get my hands on cheap! Supermarket got Chickens at half price to get rid of overstocking situation? In I go, and buy as many as I can get, prep them, can them, and when prices are high, I enjoy my half-priced stuff, no refrigeration costs added! Got an over-purchase of carrots two years ago for nearly nothing, canned them, gave carrot space in garden over to beets two years running now, and I am still laughing at the supermarket manager! See a veggie bargain in the fall and wish you could get those prices year-round? You can, You can! Seriously, I got salmon on a huge sale, canned the whole lot, and have great salmon whenever I want, much better than half-price, because to the fishmonger, it is a “perishable” but to me it is cannable! You do have to “get when the getting is good” and can fast and furious for a day or more every now and then, and you need a good supply of the reusable jars and new lids on hand, but you can really save a lot of money this way! We have a local farmer lets “poor folk” go over his tomato patch when he is done, for the smaller, misshapen, odd-ball tomatoes – we visit him every season and go canning crazy when we get home! Over the years, we have built up a good inventory of jars, from neighbors who gave up canning, yard sales, and folks who watch and collect such things just for us, so our “jar” costs are nothing. We use new lids every time, bought at the “Dollar Shop” or other bargain spots – Walmart had an end of season sale that did us a big favor last year!Lid costs can be kept minimal! Luckily we have a big old gas stove running on natural gas in our kitchen, and it serves as the cheap heat source for this endeavor. The rest is joyous labor of enthusiastically packing away secure food supplies for up to even three years ahead! and in these kind of times, that feels very good! I like drying food too, but that’s another story!

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  16. It seems you don’t know about the canning jar lids having the same bpa-containing lining as metal food cans. I was looking for info on whether the natural rubber rings used with Weck and other all-glass jar and lid combos are safe, but I guess you haven’t caught up to this issue yet!