Don’t want your tomatoes to go to waste after the summer season ends? Use this easy and straight-forward beginner’s guide to canning tomatoes to enjoy tomatoes from the garden year-round!
However, it only takes a few plants to suddenly become overrun with tomatoes. And when you’ve eaten your fill of Hearty Spaghetti Sauce and Tomato Basil Soup, what else can you possibly make with all those tomatoes?
The answer – canning tomatoes!
Beginner’s Guide to Canning Tomatoes
The idea of canning can sound scary, but it’s like riding a bike – once you get the hang of it, it’ll never be hard again!
Plus, this beginner’s guide will explain exactly what to do – step-by-step – so you can take advantage of garden harvest tomatoes in August, farmer’s market tomatoes, or even a good deal at the grocery store, all year long!
What You Need for Canning Tomatoes
- Canning Jars: You need jars specifically made for canning (Ball and Weck are good brands) in either a 16 oz pint size or a 32 oz quart size. I tend to find the best deal on canning jars at Walmart, but these on Amazon are a good deal too. You can, however, re-use canning jars. If someone gives you gifts in mason jars, keep them!
- Canning Lids: Canning lids come with canning jars when you buy them, but it’s best practice to use new lids every time you can.
- Canning Rings: Also known as screw bands, you can reuse canning rings from canning jars. Do a quick count and make sure you have one ring for each jar you plan to can with.
- Canning Pot: You need one pot big enough to cover your jars plus 2″ of water. If you chose pint jars, you could probably use the typical 5-quart pot that comes with most cooking sets. If you’re using quart jars, you’ll need a big stock pot or canning pot. Using racks in the pot is optional.
- Small Saucepan: A small one like this that comes in your cooking set will work. It’s to keep the lids warm while you prepare the tomatoes and jars.
- Sharp Knife: For cutting tomatoes, I love this one.
- Cutting board
- One cookie sheet OR another large pot: Some canners keep the jars warm in the oven on a cookie sheet; others keep them warm in a big pot of water. Choose whichever method suits you.
Optional Tools for Removing Skins
- Medium Pot (optional, for removing skins): if you want to remove the skin because it’s tough or doesn’t taste good, you’ll need this.
- A big bowl of ice water (for removing skins, optional)
For most canning projects, you’ll probably already have most of these supplies. Double check you have enough jars in good condition (no chips or cracks), enough lids, and that your pots aren’t being used in another recipe and you’re good to go!
Ingredients to Can Tomatoes
This tutorial is for making diced canned tomatoes using ONLY tomatoes. If you want to can tomatoes using onion, peppers, garlic, carrots, or celery, you’re essentially canning salsa and you should follow the appropriate process times.
- Lots of firm raw tomatoes. Fresh ripe tomatoes are best for this recipe as they provide the most flavor!
- Lemon juice. Bottled lemon juice is best for canning because the acidity level is consistent.
Note: This is everything you need for the cold-pack method, which is canning food that hasn’t been cooked. You can follow this guide for the hot-packing method of canning tomatoes.
How to: Canning Tomatoes Tutorial
Step 1: PREP
Optional, if Removing Skins: Fill the MEDIUM pot ⅔ full with water and bring to a boil. (See additional recipe notes for more on removing the skins from the tomatoes.)
Warm the Canning Jars. Jars must be the same temperature as the water you’re canning them in. If you’re using…
- Cookie Sheets: Preheat the oven to 250F. Place the empty jars on the cookie sheets and place them inside the oven.
- Large Pot: Fill the pot half full with water and place empty jars inside. Bring to a simmer.
Simmer. Fill the SMALL saucepan with a couple of inches of water and place the lids inside. Bring to a simmer on a back burner.
Optional, if Removing Skins: Fill a big bowl halfway with ice water to create an ice bath.
Catch-Up. At this point, you should have up to 4 pots on the stove:
- CANNING pot for water bath canning
- COOKIE SHEET in the oven with jars on top, or a second large pot of water for warming jars
- (optional) MEDIUM pot for de-skinning
- SMALL saucepan for lids
Step 2: INSTRUCTIONS TO REMOVE THE SKINS (OPTIONAL)
- Remove the stems from the tomatoes and cut a small “X” at the bottom of the tomato. Place as many tomatoes that will comfortably fit in the medium pot, leaving about 1″ of water covering them. Dip the tomatoes in the boiling water for 30 seconds (use a kitchen timer).
- Use a slotted spoon to remove the hot tomatoes from the hot water and place them directly into the bowl of ice water.
- Allow them to sit in the water until they are cool to the touch.
- When cool, remove the tomatoes from the cold water and set aside to remove the skins. Repeat this process for the remaining tomatoes.
- When all the tomatoes have been boiled and cooled, peel the skins off and set aside.
Step 3: DICING THE TOMATOES
- Using your knife, carefully cut the tomatoes (peeled or unpeeled) into small pieces. The actual size of the diced tomato is a matter of personal preference. I cut my tomatoes (1-2″ in diameter) into pieces that are ⅓″ – ½″ in size. Simply quarter tomatoes if they are on the smaller side. You can also slightly crush the tomatoes if desired.
- As you’re working through the tomatoes, set aside any scraps and juice. They’ll come in handy in a moment!
- Remember that this tutorial is for the cold-packing method, not the hot-pack method. You want your tomatoes to be uncooked and raw.
Step 4: JARRING TOMATOES
- When all your tomatoes are diced, pull out as many jars from the oven that will fit in your big pot (mine holds 6) and start filling them up with the tomato mixture! You want to pack tomatoes in the jars lightly but well. Shuffle the jar on the counter to help the tomatoes settle into the nooks and crannies. Leave about ½-inch headspace at the top of the jar for expansion.
- When your jars are filled, add lemon juice to each jar. Use 1 tablespoon for pint jars and 2 tablespoons for quart jars.
- Measure salt into each jar. Use ½ teaspoon for pint jars and 1 teaspoon for quart jars.
- Fill jars with liquid, leaving ½″ of room at the top. You can fill the jars with either water or tomato puree. Personally, I chose tomato puree because it enhances the flavor of the homemade canned diced tomatoes and lets me use up my tomato scraps. (See the next step.)
- If you choose tomato puree, toss all your tomato juice, scraps, and skins you’ve been saving into a blender and puree until super smooth. You can then press tomatoes through a sieve if you’d like (I usually don’t).
- As you fill the hot jars with puree (or water), slide a chopstick or butter knife around the inside edge of the jar to remove as many air bubbles as possible. Rotating the jar back and forth on the counter (in a half-circle motion) also helps. Make sure to wipe the rim if any moisture is on the lip.
Step 5: WATER BATH CANNING TOMATOES (How to Can Tomatoes Without a Canner)
- When the jars are filled, carefully remove the lid and ring from the small pot of simmering water. Place the lid on the can, then the ring on, securing just enough so the lid stays on and doesn’t fall off. You don’t want to overly tighten the ring at this point. My trick is to turn it until it catches (and I can’t pull it straight off) and then another quarter turn.
- Place the jars in the canning bath and let them boil submerged in water. Processing times depend on your added liquid: 45 minutes if you used water or 85 minutes if you used tomato puree. Set the timer and occasionally check the water level to ensure it can stay covered.
Note: This is for the water bath method at an altitude of 0-1000 feet above sea level. If your elevation is different or you are seeking a different canning method, use this guide from the National Center for Home Preservation.
Step 6: COOLING THE CANNED DICED TOMATOES
- When the timer goes off, carefully remove the cans from the water bath (this is when a canning kit with a jar lifter comes in handy) and set them aside on a towel to cool for 24 hours until they reach room temperature. You should hear some popping over the hours as the lids seal themselves.
- Check for a good seal by pushing down on the center of the lid. If it doesn’t bounce back, you’re good. If it does bounce back, repeat the water bath method in the next batch OR put unsealed jars in the refrigerator and include them in a meal in the next few days. You can also freeze the tomatoes if you don’t have any meal ideas for tomatoes in the next few days.
- When the first batch of canned tomatoes is cooling, check to ensure you have enough water in your pot, adding more water if necessary. Then start working on the second batch by repeating the same process again.
- When all the tomatoes have been canned, cooled, and sealed, put them away and congratulate yourself for a job well done!
Homemade Canned Diced Tomatoes FAQs
Should you remove the skins from your tomatoes?
1. It depends on a) your preference and b) the type of tomato you’re canning.
2. If you like smooth, skinless tomatoes, remove the skins. If you’re canning tomatoes with tough skins (in general, the bigger the tomato, the tougher the skin), then you might want to remove the skins.
3. Me? My tomatoes are only 1-2″ in diameter, and I don’t really care if there are skins in my sauce, so I kept the skins on.
Is canning tomatoes difficult?
Canning your own tomatoes is NOT difficult at all. Seriously. If you think it is, it’s your mind playing tricks on you. Push the little voice aside and listen to me: It looks hard, but it’s really not.
Can I speed up the process?
Yes! Working in batches makes this process go MUCH faster. That means taking the skin off all the tomatoes at the same time, then dicing all the tomatoes at the same time, then putting them in jars at the same time… catch my drift? This process works really well – just make sure you have enough bowls and containers to hold your tomatoes.
How long do you can tomatoes in a hot water bath?
Tomatoes need to process for 45 minutes if you use water, or 85 minutes if you use tomato puree.
Do you have to can tomatoes in a water bath?
No! You can use a pressure canner to can tomatoes. Using a water bath is easier for some because you don’t need any special equipment, like a pressure canner.
More Questions on Canning Tomatoes
Do you really need lemon juice when canning tomatoes?
Yes! Tomatoes are naturally high-acid foods, but the ph needs to reach a safe acidity point to kill bacteria when you can AND prevent bacteria, molds, and spoilage from forming as the tomatoes sit on your pantry shelf. Vinegar or adding a teaspoon of citric acid are not suitable substitutes.
Can I use bottled lemon juice?
Absolutely! The lemon juice is purely to produce a high level of citric acid in the jars to keep the tomatoes to preserve the tomatoes. Bottled lemon juice has a consistent level of acidity, so it actually works better than fresh!
How many cans do 1-2 pounds of tomatoes make?
If you only have 1-2 pounds of tomatoes, you might only be able to squeeze 1 can from this recipe, which is about half of one quart of tomatoes. That being said, you’re going to want a TON of tomatoes, aka several pounds, to make this home canning process worth it. Otherwise, going through the trouble of canning them might not benefit you. You’re probably better off just freezing them whole or eating them up.
Can I use this process for whole tomatoes?
Yes! You can use this same process for whole tomatoes or halved tomatoes. Stewed tomatoes, crushed tomatoes will require a slightly different process that I have not tested.
What kind of tomatoes should I use for this method?
I recommend using Roma tomatoes or other larger, fleshy tomatoes for this method. Roma tomatoes and other large tomatoes have a lot of flesh and very little juice and seeds, making them perfect for use in sauces.
Do I need a pressure canner for this canning method?
Nope! A pressure canner is not needed for this canned tomato recipe. This is great news for those who are scared by the gauges, weighted gauge, and or gauge pressure on pressure canners!
The high acidity of the tomatoes makes them like other fruits when canning. Low-acid foods, on the other hand, would require a pressure canner.
Canning your own tomatoes at home has never been easier! Now that you have all the steps you need to can tomatoes at home, you’ll never go back to purchasing store-bought cans of tomatoes again! Try out this home food preservation method, and let me know what you think!
More Tomato Recipes for Food Preservation
- Homemade Tomato Sauce
- 15 Minute Spaghetti Sauce
- How to Make Tomato Powder
- How to Freeze Tomato Paste