Canning Organic Roasted Tomatoes and Sauce


I have been growing our own organic vegetable since I moved to Southern Ontario 9 years ago. Growing up in Glasgow, Scotland and living in other city and suburban areas, I didn’t do a lot of serious gardening before, although I did do some container gardening, grew herbs, and a little backyard gardening.

There is nothing better than picking and eating fresh vegetables that you know don’t have any chemicals on them! But here in Ontario, we only have so long to grow heat loving tomatoes, so we like to preserve them for a taste of summer in the winter!

Making your own organic tomato sauce not only saves money, but is so much better than what you buy, plus you know what is in it, and not in it! There is something so satisfying about seeing a big batch of beautiful jars of food you have grown, and canned yourself!

So this year I did my sauce a bit differently and it turned out so amazing, I am never going to make it any other way! Instead of cooking down the tomatoes on the stovetop and steaming up the house I roasted them on the barbecue grill! You can also roast them in the oven, which is how I did our canned tomatoes this year, and they were amazing too! What I like best is not only the amazing flavour, but the bright colour and that you get a lovely thick sauce in less time. And with the roasted canned tomatoes, you get more tomatoes in the jar and a lot less tomato juice on the bottom of the jar.

Also, as I mentioned in a prior post, we like to live as chemical-free as possible, so before I start, I wipe down everything with our favourite, eco-friendly, non-toxic disinfectant. This hospital-grade EPA-registered botanical disinfectant kills over 99.9% of common household germs. Everyday cleaners don’t kill bacteria and viruses. In fact, when using an everyday cleaner and a cleaning rag or sponge, you could simply be spreading the germs around. One single bacteria cell can multiply into over a billion in just 24 hours. And if you are growing and canning organic, you certainly don’t want nasty chemicals like bleach in your food!

Here is my recipe for the Roasted Tomato Sauce:


  • 20 lbs. of ripe tomatoes, preferably heirloom paste and sauce type such as roma
  • 3 cups chopped onions
  • 8 medium garlic cloves, chopped
  • 2 Tbsp. olive oil
  • 2 Tbsp. balsamic vinegar
  • 2 Tbsp. canning salt
  • 1 Tbsp. dried oregano
  • 1/4 cup finely chopped fresh basil (or 1 Tbsp. dried)
  • freshly ground pepper, approx. 2-3 tsp.
  • citric acid – 1/4 tsp. per pint

Heat up the barbecue on high for all burners. I use a big ceramic disk on one side and cast iron trivets on the other side that I have to put under pots on the stove to prevent things sticking, but a ceramic pizza baking disk, fire bricks, etc. would work too. The first time I did half the recipe and put my roasting pan on one side of the grill, turning down that side of the grill and leaving the other side on high. You can also roast in the oven at 450ºF.

Wash tomatoes, cut in half, and put into a roasting pan (make sure it fits in your grill!) that you have rubbed a bit of olive oil all over bottom and sides. I divide between two roasting pans, one large and one smaller that both fit on the grill.

Add the rest of the ingredients to the tomatoes dividing to the proportions of tomatoes if using two roasting pans. Gently stir and place onto the grill, closing the lid. I turn down my heat a little bit so temperature stays around 500-600ºF. or so.

Roast for a couple hours, checking and stirring from time to time. Once tomatoes have cooked down enough, I put the tomatoes from the smaller roaster into the larger one and keep cooking until they are reduced enough for a thick sauce. One batch I cooked way down and made into tomato paste! You can also cook down a bit more on the stove top later, if you decide you want your sauce thicker.

After the roasted tomatoes have cooled enough to handle, run them through a sauce press. Here is my ancient one I got at a thrift store, but you can find them at most Home Hardware stores in Canada, or on Amazon. This contraption takes all the skins and seeds out, and does it really fast!

As my pan fills up, I transfer to a sauce pan and keep running the rest of the tomatoes through the press.

At this point you can heat the sauce on the stove top for a little while if you need to thicken it and also can adjust seasoning to taste. Get your canning equipment ready! After washing my canning jars, I like to put them into a 250ºF oven to dry and keep hot. We have hard water, so works better than sterilizing in the hot water bath.

Fill up your canning pot, with rack, put lids into a small sauce pan with water and heat to sterilize but don’t boil. Get clean rings ready, and other equipment such as a canning funnel and jar grabber.

Once sauce is at the desired thickness keep hot and start filling hot jars, adding 1/4 tsp. citric acid to each pint. You can add a small amount of sugar or maple syrup, if desired, but if you have used ripe tomatoes, sauce should be sweet enough! Put lids and rings on firmly, put into canning rack, and immerse in water with at least an inch covering jars. Bring back to a simmer and simmer for 35 min. for pints, 45 min. for quarts.

Remove jars from canner and let rest for 24 hrs. before removing rings and storing. Make sure lids sealed properly. Any unsealed can be re-canned or put into the fridge to use within the next few days.

For roasted canned tomatoes, I roast in tomatoes on trays in a single layer in the oven pressed close together, so I can pop off the skins, and pack into pints. They are processed the same way as the sauce, including the 1/4 tsp. citric acid, and I found I got a lot more tomatoes per jar and less liquid, than when I canned them the traditional way! Feel free to comment or contact Wendy if you have questions!

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