I wasn’t sure whether to title this How To Can Diced Tomatoes, or How to Can Crushed Tomaotes. Honestly to me they are one in the same, just different tomato chunk sizes. Either way, taking my garden fresh tomatoes and turning them into canned diced tomatoes is one of the most frugal ways to save money throughout the year. This tutorial shows you step by step how to can diced tomatoes.
Related Posts:
- How To Can Tomato Sauce
- How To Can Apple Peel Jelly
- How To Make Habanero Jelly
- How To Make Jalapeno Jelly
- Homemade Applesauce – With Canning Tutorial
What You’ll Need:
Here’s a list of what you’ll need for making and canning your own diced tomatoes.
~ Tomatoes — about 20 to 25 pounds of tomatoes
~ 12qt Saucepot* — I like using two of them for this process.
~ Large bowl*
~ Waterbath Canning Kit — I’ve had this one* since 2010. It’s been through hell and back, including being dropped on my deck, and it’s still kicking! The canner itself holds up to 7 quarts, or 9 pints, and is a breeze to use. Plus, it comes with other items you’ll need, like the headspace tool, jar lifter and funnel, without having to purchase them separately.
~ Canning Jars with Lids and Rings*
~ Ladle
~ Stainless Steel Strainer*
~ Citric Acid*
~ Small Knife
~ Measuring Spoons
~ Damp cloth for wiping the jar rim
~ Towels
Gather, Wash & Peel The Tomatoes
Every year I like to grow a variety of tomatoes. But the ones that are the best for canning as sauce are Romas*. They’re not as watery, and have a nice meaty texture. They’re not the best for eating fresh, but they hold up excellent through the whole preserving process.
When I’m canning diced tomatoes though, I’m not too picky. I’ll go for whatever tomatoes we have on hand since tomato season can leave me with a plethora of fruit and not a lot of time to process them before they go bad. This year I had a lot of Cherokee Purples, Big Rainbows, Tigerellas, Brandywine Pinks and Mortgage Lifters, and the process went just as smooth as when I use Romas.
No matter how I am preserving tomatoes though, I recommend peeling them because it makes the tomatoes a little more versatile to deal with.
Fill one of your 12qt sauce pot* with water and bring it to a simmer. While you’re waiting on the water to simmer, fill your large bowl with water and a splash of vinegar (optional), and wash the tomatoes.
Using a steak knife, score an “X” on the bottom of the tomatoes.
At this stage, I like to wash and score all my tomatoes at once, placing them on a cookie sheet or a towel. This isn’t a necessary step, but I only have one large bowl and I will need to use it again to cool the tomatoes off.
Once the water is at a low simmer, place a few tomatoes at a time in the water until the skin from the score cracks up the rest of the tomato. This can take 1 to 3 minutes depending on a few factors, including the type, size, and ripeness of the tomato.
Once the skin has peeled, use your stainless steel strainer* and fish out the tomatoes that have started to peel.
Place them in the large bowl, filled with cold water. Let the tomatoes sit for 3 to 5 minutes, or until they are able to be handled. If I’m in a hurry, I like to put a cup or two of ice into the bowl to help speed up the cooling process.
At this point the peels usually slip off nicely. If you need to, you can carefully use a steak knife to help take off stubborn spots.
Using a steak knife, core the tomato, and dice into chunks.
While I’m peeling the rest of the tomatoes, I like to use my second 12qt sauce pot* to hold the chunks.
Prep Your Canner And Jars
Once you’re done peeling all your tomatoes, put the pot they are in on the stove and bring it to a simmer over low heat. The goal is not to cook them down further, but to raise their temperature a little so when you place them in your jars and in the canner, your jars aren’t going through a temperature shock and they shatter. It’s never fun when it happens.
As you’re bringing your diced tomatoes to a low simmer, wash your jars and lids and rings with hot soapy water. Fill the jars with boiling water, and sit on the rack of your canner to remain hot. Put your lids in a bowl of hot water to help soften the seals. As of recently, this isn’t a necessary step, but it does help the lid seal easier.
How To Can Diced Tomatoes
I prefer to leave my tomatoes plain only because it makes it more versatile for any meal planning uses. This means no salt, no seasonings, just straight up tomato.
Working one jar at a time, add 1/4 teaspoon citric acid* to each pint, or 1/2 teaspoon citric acid per quart. The tomatoes need a boost in acidity to be canned safely in a waterbath.
Using a funnel, fill each jar with the diced tomatoes, leaving 1/2″ headspace. {Remember, headspace is the distance between the rim of the jar and the contents within the jar.}
Remove any air bubbles with the headspace tool, and wipe the rim with a damp cloth. This ensures that there is no food on the rim that may ruin the seal. Using the magnetic lid lifter, add the lids, and tighten with a ring until finger-tip tight.
Add the jar to your canner, and repeat for the remaining jars.
Once your jars are filled, lower the canning rack into the canner. Put the lid on, and bring to a full boil. Once at a full boil, process pints and quarts for 1 hour and 25 minutes.
Remember to adjust your cooking time for your altitude. If you are above 1,000 feet in elevation, adjust your processing time by adding 5 minutes. For example, our altitude is 1,350 feet, so I process my diced toamtoes for 1 hour and 30 minutes. If you were above 3,000 feet, you would add 10 minutes from the initial processing time, and above 6,000 feet in elevation, you would process for 15 minutes, etc. This helps compensate for the difference in boiling temperature and air pressure at higher elevations compared to sea level.
When your processing time is done, turn off the heat and remove the lid. Allow the jars to sit for 5 minutes before you remove them from the canner. Let them sit undisturbed for 12 hours, then check the seal. To do this, push down in the center of the lid. If your lid is sealed, it should not give, or “pop”. To store, remove rings, label and store in a cool place until ready for use.
If your lid did give, or “pop”, you can either reprocess your jar with a new lid, or store in the fridge to use with the next week.
Last year I had too many tomatoes and didn’t want to spend a lot of time canning them so froze them. Can you use frozen tomatoes to can?
Absolutely! We have had years where we had too many all at once too, or we were busy with fall sports, so we peeled the tomatoes and froze them whole, or juiced them and froze the juice. I’ve canned tomato sauce from frozen tomato juice and it works wonderfully, but I’m not so sure diced tomatoes would come out perfectly after being frozen since the water crystals expand during freezing. They’d probably make some amazing canned crushed tomatoes though!