As I said in my last post, there is nothing quite like a peak-of-season tomato, and the same thing goes for products — sauces, salsa, etc — made from them. Additionally, I have concerns about Bisphenol A contamination in store-bought canned tomatoes. So each summer my husband and I devote quite a bit of energy to preserving the precious summer tomatoes that we cannot eat right away.
Canning crushed tomatoes is rather laborious but it has the biggest reward — versatile base for many soup, sauce, and other recipes, that you can use year-round.
It is recommended that you start with a plum or roma variety — these have lower moisture content. I just picked up a $10 box of “canning tomatoes” from a roadside stand. I have no idea what variety they were. Definitely not plum or roma. But whatever, they worked!
You will then need to peel and de-seed the tomatoes. I have this nice food mill which works well — simply coarsely chop the tomatoes, skin, seeds and all, and grind right into the pot. It automatically removes the seeds. A tomato press is another tool meant specifically for tomatoes.
You can also do it manually by blanching the tomatoes for about 30 seconds, which allows you to easily peel the skin right off, cutting out the stem and squeezing out the seeds. Alton Brown provides a nice visual of this process at about 5:15 in this video:
Just cook down the tomatoes until the water cooks off and a nice, thick consistency is achieved.
At a minimum, you will need a large pot, some sort of rack to hold the jars above the bottom, some tongs, and a ladle. You can purchase a canner with a built-in rack designed specifically to hold jars:
I also have a set of utensils that include tongs for lifting jars, a headspace measurer, a large funnel, and a little magnetic lid-lifter. You don’t really need these things, but they are helpful if you can frequently.
Obviously, you will also need jars, lids and bands. Unfortunately, traditional Ball lids are also lined with BPA. I have heard good things about these lids, which are reusable and BPA-free. As I have a large supply of lids I need to use up, I haven’t tried these yet, but I definitely will once I need to restock. I figure that unless you are holding the jar upside-down, the tomatoes don’t really come into much contact with the lid, right?
Wash all the equipment, place the jars into the canner as pictured above and fill with water. Place on heat and bring to a boil. Place lids in a small pot of water and let simmer to sterilize.
Carefully pick up your first jar with tongs, empty the water inside, and add a tablespoon of lemon juice or vinegar. Though the high acidity of tomatoes makes them ideal for canning, this added ingredient acts as an additional preservative.
Using the funnel and a ladle, fill the jar, leaving 1/2 inch of headspace at the top. Remove a lid from the simmering pot of water and place on top of the jar. Screw on a band.
Place all jars back in the canner. Make sure there is at least an inch or so of water above the cans, and boil for 35 minutes. Let sit 5 more minutes in the canner, and carefully remove. Let sit until cool and check that each lid has sealed (should no longer pop up).
And now you have crushed tomatoes that will last up to a year in your pantry!
Other methods of preservation
(from The Big Book of Preserving the Harvest, by Carol W. Costenbader)
Tomatoes will last about 10 months in your freezer. Just package the crushed tomatoes from the recipe above into small containers and place in the freezer. Alternatively, you can place washed and dried whole tomatoes onto a cookie sheet, freeze, and then stick in a freezer bag. The skin will peel off easily as they thaw.
We have a food dehydrator which we have used for tomatoes in the past. They do not require any special pre-treatment, and can simply be sliced and placed in the dehydrator for 6-8 hours. They will keep for 6-8 months when stored in a cool, dry place in an airtight container.
If you live in a hot, dry climate, you can also dry tomatoes in the sun. Stretch and secure cheesecloth tightly over a cookie sheet, place tomatoes on top — they should dry adequately within 1-2 days.
Preserving tomatoes isn’t terribly easy, I’ll admit. Well, it is easy. Just labor- and time-intensive. But it really is so worth it. I promise you won’t regret the effort you put in to canning your summer tomatoes come December!