The tomatoes. Sigh. Due to unseasonably cool weather, our garden didn’t produce enough tomatoes for canning, although we have had plenty to eat.
So last weekend, I bought 40 pounds of tomatoes from a local farm store. And then I promptly became ill, so I didn’t get them all canned right away. Instead, I whittled away at them by making small batches of tomato sauce, as well as a batch of tomato jam (which is a story for another time).
Tomato sauce is just as easy as applesauce. It just takes more time to cook down. Thus, to use my time (and our electricity) wisely, I’ve been cooking the tomatoes in the crock pot.
We have only a three-quart crock pot, which holds about five pounds of tomatoes. This produces one quart of sauce. So this is not the method to use if you want to make a large amount of sauce. But if you just want to make sauce in small batches when you have a chance, this works. You can divide your quart into smaller jars if you wish. A half-pint jar is equivalent to the smallest cans of grocery-store tomato sauce, and a pint jar is almost the same as a medium-size can.
Also, hat tip to Betsy Richter, who tipped me off on the crock pot technique. Betsy has a wonderful recipe for roasted tomato sauce, which I’m not using because it includes onions and peppers, and the USDA recommends using a pressure canner if you’re adding anything besides tomatoes. I definitely want to try it sometime, though!
Crock Pot Tomato Sauce
- 3 quart crock pot
- 3 quart saucepan
- Food mill
- Rubber spatula
- Canning funnel
- Magnetic lid lifter
- Jar lifter tongs
- Water bath canner w/ rack
- Jars: 1 quart jar OR two pint jars OR four half-pint jars
- A metal ring and lid for each jar.
- 5-6 pounds Roma tomatoes
- Salt (optional)
- Bottled lemon juice
Wash the tomatoes. Scoop out the stem end of each (I use a tomato shark). Cut off any bruised or bad-looking spots (they can make your sauce spoil). Cut the tomatoes in half the long way. Squeeze/scoop out excess seeds and juice (I don’t work too hard at this. There will still be seeds in there for now). Leave the tomato skins on.
Put all of the tomatoes into the crock pot, and cook them on low for 10-12 hours. You can leave them to cook overnight, during work, whatever. If it goes past 12 hours, that’s fine too.
Place your food mill over the 3-quart saucepan. Run all of the tomatoes and juice through the food mill and into the pot, until all that remains is a seeds-and-skin sludge. Scrape that into your compost bin.
You’ve probably got something that looks more like tomato juice in your saucepan. Bring it to a full boil, and let it boil down to the consistency you want. I keep it on medium-high for a while, and turn it down to medium if I’m walking away. Stir it once in a while. The total time will vary, depending on your tomatoes, your stove, and your taste (I’d say 20-40 minutes). You may add up to 1 teaspoon of salt if you wish. Keep the sauce hot until you are ready to fill the jars.
While the sauce is cooking down, fill your water bath canner (or just a large pot) with enough water to reach one inch above the tops of your jars and bring it to a boil. Make sure you have some kind of rack in the bottom — the jars should never sit on the bottom of the pan. Put the empty jars in it, letting them fill with water, and boil them for ten minutes. Put the lids and rings in a smaller saucepan and boil them for ten minutes, too (then keep them in the pan on low until you need them). You can also sterilize jars by running them through the dishwasher, but for one or two jars? It’s probably not worth it, unless you’re running the dishwasher anyway.
Remove the jars from the pot, dumping the water back into the pot. Add lemon juice to each jar: 1 tablespoon per pint or two tablespoons per quart. This increases the acidity of the tomato sauce so that it can be canned safely in a water bath canner. Fill the jars with tomato sauce, leaving 1/2-inch headspace between the sauce and the top of the jar. Stir with a butter knife or narrow spatula to distribute the lemon juice and eliminate air bubbles. Wipe the rim of each jar to remove any stray sauce. Place a lid on each jar and screw the rings on finger-tight (not too tight).
Use the jar tongs to place the jars back into the boiling water. Return to a full boil if necessary, and begin timing when the water is at a full boil, 30 minutes for half-pints, 35 minutes for pints, 40 minutes for quarts. If your altitude is greater than 1000 feet, you’ll need additional time — check the USDA Complete Guide to Home Canning.
Remove the jars from the canner promptly, and let them cool without touching each other. You should hear the ping of the lids sealing fairly quickly — tomato products seem to ping faster than applesauce does. If the lid still pops up and down in the center after the jar has cooled, then that jar is NOT sealed properly. You should put it in the refrigerator and use it as soon as possible.
If anything here isn’t clear, or you have other canning questions, the USDA Complete Guide to Home Canning is a great resource, as is PickYourOwn.org.
The canning process can seem cumbersome, and it probably will be at first, but you’ll catch on after the first batch. You’ll learn how to time things so that you have the canner boiling at the same time the sauce is ready. And you can let other people help — my daughters, ages 10 and 8, have now learned to do all of the raw tomato prep, so I can concentrate on other things.
You may notice that canning your own tomato sauce doesn’t necessarily save you money. You can often get four 8-ounce cans of tomato sauce for a dollar at the grocery store. This recipe makes the same amount of tomato sauce, but you’ll pay at least $2-4 just for the tomatoes. If you grow your own (and have a good crop), you might do better. And if you can get a good price on organic tomatoes (or grow your own), you can probably beat grocery store prices for organic tomato sauce. I bought local/non-organic tomatoes for $.85/pound, but could also have bought organic heirloom tomatoes through a buying club for $1.05/pound.
Canning my own sauce does, however, help me avoid the BPA-lined cans from the supermarket. And yes, it is satisfying to produce it myself.