Each year, when I consider what my priorities for home canning, tomatoes are at the top of my list. My reasons include:
1. Store bought canned tomatoes taste hugely inferior to home canned.
2. Store bought tomatoes usually contain dye to make the tomatoes look more red.
3. Store bought tomatoes usually use fruit that wasn't fully ripe, reducing flavor and nutrition.
4. Store bought tomatoes are usually loaded with sodium.
5. Store bought tomatoes are considered one of the foods most likely to pass BPA into your body because the acid in the tomatoes leaches the BPA out of cans very readily. (Read about BPA and health at the Mayo Clinic website.)
6. Store bought tomatoes are exposed to Teflon in the can (and Teflon exposure may lead to health problems; read about Teflon and cancer at the Mayo Clinic website).
The good news is, tomatoes are easy to can at home. Buy them in season (summer) and shop around for a good price. I usually find them at 99 cents a pound from a local farm. This year, I put up 35 quarts of tomatoes for $69.30 - a bargain, when you consider quality and health concerns. I even got a few quarts of tomato juice out of the deal.
You can certainly use home grown tomatoes, too. In fact, if you freeze them as they come in, it's even easier to remove their skins (see instructions here). But don't bother canning grocery store tomatoes; they have too little flavor.
There is more than one way to can tomatoes, but I'm going to show you how to do it my favorite way: Cut into quarters and canned in the tomatoes' own juice. I find this a versatile method since tomatoes are easy to crush or cut up in the pan with a fork while I'm cooking. In the past, I've also canned tomatoes in water, but as long as the tomatoes are truly ripe, juice will naturally come from them while canning. Canning in juice gives you more tomato flavor.
You may use either a boiling water bath canner or a pressure canner. I'll show you how to do it both ways, starting with the water bath canner. Before you begin, please review the general water bath and pressure canner guidelines. Either type of canner produces the same results; however, a pressure canner will keep your kitchen cooler. Also, be sure to use only non-reactive pots and pans or the tomatoes will taste tin-y.
What You Need:
Bottled lemon juice
Water bath or presser canner
Canning lids and screw bands
1 saucepan (for lids)
Plastic utensil with long handle (for bubbling)
Paper towels or cloths
How to Do It (with a water bath canner):
1. Prepare jars and lids.
2. Fill a clean sink with ice water. If you don't have ice, it's okay to use very cold tap water.
3. Fill the large pot with water and bring it to a boil. Add a few tomatoes at a time to the boiling water. Within 30 to 60 seconds, their skins should split. (Occasionally, I run across tomatoes that need about 2 minutes to split, but keep an eye on them. You don't want to cook the tomatoes.) As soon as a tomato's skin splits, remove it from the pot with a slotted spoon and place it in the sink. Repeat this procedure until you either have a sink full of tomatoes or have used up all the tomatoes.
4. Slip the skins off the tomatoes; they should come off easily. Compost the skins.
5. Cut the tomatoes into halves, thirds, or quarters, removing any bruised sections, as well as the green core. Place the cut tomatoes in the large bowl. When full, you should not only have tomato pieces, but also tomato juice in the bowl. (If not, simmer some water on the stove and use it in place of the tomato juice.)
6. Working with one jar at a time, pour 1 tablespoon of bottled lemon juice into a pint jar or 2 tablespoons of bottled lemon juice into a quart jar. Pack tomatoes into the jar. Using a funnel makes it less likely to have a seal failure due to a dirty jar rim. Press down gently on the tomatoes so you can get a good pack, but leave 1/2 inch headspace. Ladle tomato juice into the jar, maintaining the 1/2 inch headspace.
7. Remove bubbles from the jar and wipe the rim of the jar clean with a fresh towel or cloth.
8. Use a lid lifter to place a lid on the jar, then add a screwband. For jars filled with water (not tomato juice), process in a boiling water bath canner for 40 minutes if using pints and 45 minutes if using quarts. For jars filled with tomato juice (not water), process pint and quart jars for 85 minutes.*
How to Do It (with a pressure canner):
1. Follow steps 1 through 7, above, except make sure there is 1 inch headspace.
2. Once the jars are all in the canner, put the lid on and allow the canner to vent for 10 minutes. Close the vent and bring the canner to 10 lbs. pressure. Process pint and quart jars packed with water (not juice) for 10 minutes. Process pint and quart jars with juice (not water) for 25 minutes. *
If you have left over tomato juice, can it, too! Strain the juice to remove seeds. Add 1 tablespoon of bottled lemon juice for pint jars and 2 tablespoons for quart jars. Process pints and quarts for 15 minutes in a pressure canner - or, in a water bath canner, process pints for 35 minutes and quarts for 40 minutes.*
** NOTE: If you live at a high altitude, read this important information about adjusting canning times.