Monday, 3 September 2007

Canning Tomatoes

Well, once you've actually gone and bought that bushel of tomatoes, you are committed. (Maybe if you think having every burner on your stove going full blast for 6 hours in September is a good idea, you should be committed, but that's not my concern. My concern is how to can those tomatoes.) We like to just crush them, stuff them in jars, and call that done. More or less.

What you need:

1 bushel plum tomatoes
24 1 litre (1 quart) canning jars (fewer really, but better safe than sorry)
lids and rings for the above
bottled lemon juice
pickling salt (coarse and non-iodized)

The first thing to do is to blanch and peel all the tomatoes. This works well with 2 people. One person peels; the other person does everything else. The peeler will still fall behind.

Batches of tomatoes are dropped into a boiling water bath. We find 1 1/2 minutes to be the right amount of time. Then they go into cold water. From there, the peeler (me in this case) fishes them out, cuts out the cores, and slips the skins off.

I give the peels their own container. Otherwise, there is enough juice left in them that by the time you are done, the counter will be awash in slightly sticky tomato juice. It kind of will be anyway, but if you don't keep them contained, it will be really awash.

Blanching the tomatoes. Note; after blanching and peeling for about 10 minutes, it's time to start sterilizing jars. It takes a long time for that enormous pot of water to come to a boil - expect about half an hour - and once it does, the jars need to boil for 10 minutes to be sterilized. Add a splash of white vinegar to the water if your water is hard.

There you are; a bushel of peeled and mostly crushed tomatoes, with their peels discarded in the near bowl. As you can see, you will likely need to pull out every large bowl you own in order to have a place for everything. I dump the tomatoes in the food processor as I peel, and whenever it becomes full, my canning partner whizzes them for about a minute, then dumps them into one of the bowls.

As soon as the jars begin to boil, put about 7 litres of crushed tomatoes on to boil as well.

When you are taking the jars out of the water, dump about half of it back into the pot.

Dump the other half down the sink. Do as I say, not as I do, and don't leave dirty dishes in the sink while you are doing this! This (the dumping, not the dishes) will keep the water level in the canner at a reasonable level as jars go in and out.

Once the jars are sterilized and emptied, put 1 teaspoon salt and 2 tablespoons bottled lemon juice into each jar.

Using sterilized utensils, fill the jars with the boiling hot tomatoes. They don't have to cook; just bring them up to a boil then fill the jars.

Once the jars are filled, wipe the rims with a paper towel which has been dipped in the boiling water, to make sure the rims and edges are clean.

Next, top them with the lids. The lids must be boiled according to the manufacturers directions; i.e. for 5 minutes.

And seal them with the rings, likewise boiled for 5 minutes. They should be firmly on, but don't wrench them. There needs to be allowance for a bunch of expansion and contraction to happen as part of the process.

Back into the canner they go - leave it on while you fill the jars - and boil them for 45 minutes. Make sure the water covers the jars by at least an inch.

And there they are; the finished jars of tomatoes. The white powder on them is from our water, which is hard enough to use to make bricks. When I put the jars on to boil at the start, I put in a slosh of white vinegar. It helps keep the calcium from welding itself all over the jars.

When the jars are sufficiently cooled, and have sealed themselves (plink!) wipe them, label them with the date and batch number, and put them away. If any don't seal themselves, put them in the fridge and use them reasonably soon. You can tell the jars are sealed when the lid is concave, and cannot be wiggled. If the lid moves when you press down, it has not sealed. They generally - but not always - also make a distinctive plinking sound as they seal as well.

Most canners hold 7 jars. So, you will need to repeat the empty jar boiling/tomato boiling/jar filling/filled jar boiling process until all the tomatoes are done. We had a very generous bushel, and ended up with 23 jars. Yes, that meant our last batch consisted of 2 bloody jars. Yes, we were kind of pissed. If we had any sense we would have just put them in the fridge and used them this week. Oh well. Normally, I would say that 21 jars (or 3 batches exactly) is a realistic expectation from a bushel of tomatoes.

Happy canning!


GretnaMom said...

I have 2 questions:

1) Does the lemon juice change the taste of the tomatoes? I plan to use the canned tomatoes to make spaghetti sauce and chili among other things!

2) Is Kosher salt the same as pickling salt? if not what is the difference?

Ferdzy said...

Hi GretnaMom;

The lemon juice does not really affect the flavour. If you are tasting them plain and really thinking about it, you might be able to pick it out, but mostly they just taste like somewhat acidic tomatoes. I use them in chili, sauce, soup etc without any problems.

Kosher salt is not the same as pickling salt, although they tend to look very similar. Pickling salt is a really pure salt without any additives, and it's usually fairly coarse (although that bit is not important). Other salts, including kosher salt, may contain additives, mostly anti-caking agents (salt tends to absorb water then clump) and iodine (iodine deficiencies cause goiter). However, these additives may cause canned goods and preserves to go cloudy or form a precipitate. That's not really serious either, just kinda ugly.

cmatta said...


Thanks for the great site!

Regarding tomatoes specifically, do you HAVE to use pickling salt or can you can the tomatoes unsalted?

Ferdzy said...

cmatta, you can leave the salt out altogether if that's what you would like.

And thank you for commenting!

annemarie said...

Very helpful. Thank you.