This blog is part of a series about preserving food so you can eat local all year long. I’ve collected them all into a free course that you can access here. The course includes lessons that explain the basic preservation methods of canning, freezing, and dehydrating, and specific examples of how I use these preserving methods in combination to preserve tomatoes and corn on the cob – two of my favorite foods!
Tomatoes are such a favorite for me that I’m devoting several blogs to the various ways of preserving them. There are four lessons on this in the free Preserving Local Food course, including tomato paste and sun dried tomatoes. These specific examples will demonstrate how you can use various preserving methods (canning, freezing, and dehydrating) in combination to preserve your favorite local foods.
Last year I turned about 30 pounds of fresh Roma tomatoes from my farmers market into 17 quarts of canned tomatoes for year round cooking. These canned tomatoes are great for:
- other soups and stews
- pasta dishes
- any recipe that calls for canned tomatoes (in which you previously used diced, crushed, or other style canned tomatoes you purchased from the grocery store)
- Baking sheet or other large flat pan for roasting
- 7- to 8-quart stainless steel, enamel, or non-stick heavy pot
- Quart jars and lids (you could use pints or another size if you prefer)
- Canning supplies (see the Water Bath Canning lesson for details)
- Common kitchen utensils, such as a wooden spoon, ladle, paring knife, and cutting board
- Fresh, ripe tomatoes (the quantity is up to you; the recipe below works for any amount)
Step-by-step Instructions for Canned Tomatoes
(download a printable version)
Note that the recipe works well for whole, halved, quartered, or diced tomatoes. Feel free to make whichever you tend to cook with the most, or a combination. I recommend referencing this recipe for more information.
- Cut tomatoes to the desired size and cut out the core/stem.
- I quartered mine, but you can cut yours in half, a smaller dice or leave them whole; however you prefer.
- Also, I chose to leave the skin on since its full of good nutrients.
- If you want to remove the skins, I recommend a quick blanch (dip the tomatoes into boiling water for a 30-60 second) to loosen the skins, immediately plunge into cold water, and then slip the skins off with your fingers.
- Following the advice of Anne-Marie Bonneau (AKA Zero Waste Chef) I roasted mine for about 2 hours at 225F to concentrate the flavor just a bit before canning them. This is, of course, an optional step.
- Prepare boiling water canner (see the Water Bath Canning lesson for details supplies and the overall canning process). Heat jars in simmering water until ready to use, do not boil. Wash lids in warm soapy water and set aside with bands.
- Add 2 Tablespoons lemon juice to each hot quart jar (or 1 Tablespoon if you’re using pints).
- Pack tomatoes in hot jars, pressing down, until space between tomatoes fills with juice, leaving 1/2 inch headspace.
- Remove air bubbles. Wipe jar rim. Center lid on jar and apply band, adjust to fingertip tight. Place jar in boiling water canner. Repeat until all jars are filled.
- Process jars 1 hour and 25 minutes (for both pints and quarts, adjusting for altitude).
- Turn off heat, remove canner/pot lid, let jars stand 5 minutes.
- Remove jars and cool 12-24 hours. Check lids for seal, they should not flex when center is pressed.
How many tomatoes should you buy and can?
This is a tricky question, but a really important one to discuss. You’ll probably have to experiment over several years to really answer it well, but to get yourself close right now, I recommend asking yourself the following questions:
- How do I plan to cook with the canned tomatoes?
- What specific recipes call for them and in what quantities?
- How often do we usually eat these dishes?
- Do I wish to eat more or less this year?
Based on your answers to these questions, I recommend this amazing chart to help you decide how many bushels or pounds to buy.
It might also be helpful to approach this from the other direction… to start with one bushel of tomatoes, can them in your favorite style (whole, halved, quartered, or diced) and see how much of the canned tomatoes your family eats. Then you can adjust next year.
For reference, I canned 30 pounds of tomatoes into 17 quarts and we didn’t quite use them up last year. I found that we used canned tomato sauce, frozen tomatoes, and tomato paste much more often than these canned tomatoes (more to come on each of these in the following lessons).
Here’s an example from the Water Bath Canning lesson in case it’s helpful:
Let’s imagine you’re canning tomatoes for making chili, you normally eat chili once per week, and your recipe calls for two 28-ounce cans of diced, crushed, or whole tomatoes.
In this case, I would recommend you can your tomatoes in quart jars. Quart jars are 32 ounces each, so I would recommend planning on 2 quarts per batch of chili. Since there are 52 weeks in the year, I’m going to guess you eat chili once a week for about half the year… thats 26 times per year… and you need 2 quarts per batch, so I would recommend making about 50 quarts of canned tomatoes.
You need about 2.5-3.5 pounds of ripe tomatoes per quart jar. If you buy your tomatoes by the pound, that means you should buy approximately 150 pounds of tomatoes from your farmers market or farm stand.
Most of the time I buy my tomatoes by the bushel, so we need one more conversion. According to this chart (which will help you make this similar calculation for all other fruits and vegetables), one bushel of tomatoes is 53 pounds, so you would need to buy 3 bushels.
Please share your thoughts, questions, and experience canning tomatoes in the comments! How do you slice them (diced, quartered, halved or whole)? How many canned tomatoes do you use each year? Please tell us about it!