Have tomatoes coming out your ears? Here’s a recipe showing you exactly how to Can Diced Tomatoes!
Are home grown tomatoes one of your favorite things?
I honestly can’t think of anything better right now. This year we planted a bunch of heirloom tomatoes, mostly brandywine, and they’re my absolute favorite both for eating fresh, and for canning diced tomatoes with.
I don’t know how to explain them other than that they’re the most tomatoey tomato that ever tomatoed.
Deep pink, smooth texture, sweet, and deliciously acid flavor. So good!
Last week we harvested quite a few, and stocked up on canned diced tomatoes that we’ll probably use mostly in instant pot chili throughout the winter (don’t hate me – I love tomatoes and even beans in my chili – in fact, I can chili beans too!)
That’s one of the things I love the most about canning – once your jars are sealed, it doesn’t matter how small your freezer is, or if you have a power outage – your tomatoes are all good, ready to use then you need them.
Okay, so what do you need to know about canning diced tomatoes?
How to can diced tomatoes
- Have you ever wondered why when you buy diced tomatoes, you open a can of tomato chunk and juice, but when you open home-canned tomatoes, you pour out a jar of chunk and water? That’s because exposing a raw tomato to air by cutting or crushing it activates a natural enzyme that breaks down the pectin, causing the liquids and solids to separate. So, when you’re working with tomatoes to can, work in small batches so you can heat them and stop that enzyme immediately. That said, for diced tomatoes, in my opinion, it’s not super important whether the juice separates or not. It tastes the same, and if it’s easier to work in larger batches, go for it!
- You’re going to need a canning kettle. Tomatoes are generally water-bath canned unless they are combined with other vegetables, so you’re going to need a kettle or pot tall enough to cover the jars you put in it with at least an inch of water.
- You need a rack to separate the jar from the bottom of the kettle. The direct heat from the kettle can cause your jars to crack otherwise. You can buy a proper (inexpensive) canning kettle with a rack here (or probably at your local Walmart). In a pinch, you can also line the bottom of your kettle with a kitchen towel. This will ruin your towel eventually though, and while I’ve had many friends who do this, I don’t personally feel comfortable with it, so I use a large stock pot with the rack from my pressure canner in the bottom, or my waterbath canning kettle.
- Tomatoes are considered an acid food, however, they typically sit at about a pH of 4.6 (depending on variety, growing conditions, etc.), which puts them very close to the dividing line between high and low acid foods. I tested my heirloom tomatoes and sure enough, that’s right where they were on the pH scale. As a result, home-canned tomato products need to be acidified to be considered safe to can. This may be done using Ascorbic acid powder, citric acid, or, most commonly lemon juice. Bottled lemon juice is best and easiest to use, because it has a consistent pH, and takes the guesswork (or pH testing) out.
So now that we have the jargon out of the way, let’s get to canning!
How to Can Diced Tomatoes
- Start by sterilizing your jars and lids
- Working in small batches, dunk clean tomatoes in boiling water for 30-45 seconds, to just loosen or crack the skin
- Immediately remove, and let cool while you dunk the next batch
- Remove skin (it should slip right off), and core tomatoes
- Dice, or to make large batches quickly, whirl in the food processor
- Pack into sterilized jars to within ½ an inch of the lid
- For each pint add 1 Tablespoon of lemon juice, or ¼ teaspoon of citric acid
- Wipe rims clean, and fit with lid and ring
- Fit inner rack inside of canning kettle and fill about half full of cool or lukewarm water
- Add jars and begin heating
- Bring to a rolling boil, and continue boiling for 40 minutes
- Remove from heat. If you have the time, just let the whole kettle cool with the jars of tomatoes inside.
- If you don’t, remove the lid and let cool for 10 minutes, then carefully remove jars from kettle, keeping them away from drafts. Cover hot jars with a bath towel to protect them from drafts (and breakage drafts can cause) as they cool.
- Leave rings on jars at least 24 hours before removing to store jars in a cool, dark place until ready to use.