Canning Tomatoes as Spaghetti Sauce and Tomato Juice

Tomatoes growing in Whakatete Bay, New Zealand

One of our tomato patches

Our tomato plants were very late getting started this year.  I don’t know whether it was because it was too cold at first, or there wasn’t enough sunlight where we planted them, or something else.  But once they started going, they really went well, and we have LOTS of tomatoes.  True, our tomatoes are mostly smaller than some, but they sure do taste yummy.

Tomatoes growing in Whakatete Bay, New Zealand

Our other tomato patch (click to enlarge)

Because so many tomatoes came ripe at the same time, we decided to try some recipes for tomatoes.  With a small batch of tomatoes a couple weeks ago, we simply stewed the tomatoes, mushed them up, added some sugar and salt, and then canned (jarred) them.  This turned out to be very watery tomato paste.

So, when we got a really large batch of ripe tomatoes, we decided to try something different.  We decided to make spaghetti sauce and tomato juice.  With spaghetti sauce, you don’t want all the water from inside the tomatoes, but with juice, you do.  So, we figured we could get both from the same batch of tomatoes.

Peeling tomatoes after boiling water bath and cold water bath

peeling tomatoes is easy

For almost any tomato recipe, you need to remove the skins from the tomatoes.  Fortunately, we read early-on that you can easily remove the tomato skins by dunking them for half a minute or so in boiling water, until their skins break a bit, and then dump them into cold water for another half minute or so.  The hot water, as I said, breaks the skin, and the cold water then makes the skin come off easily.  Just pull on the skin, and it all comes loose very nicely.

Coring tomatoes

Removing cores from tomatoes is also not difficult

The next step to to core the tomatoes.  I wasn’t really sure what all that entailed, so back to the internet to find an answer.  It turns out that it simply means to cut out the spot where the tomato connected to the plant, as well as the center bit that runs through the tomato from top to bottom.  Hold the tomato in one hand, jab a knife into the top near the stem, and cut a circle around it.  Then reach further into the tomato and cut across the center down inside the tomato, and pry up with the knife.  Some of our tomatoes, though, had tougher cores, and we didn’t cut quite deep enough to get out all the yucky bits.  So, when we were stewing the tomatoes (in the next step), we had to scoop out some of the white core bits, quite a tedious job.

peeled and cored tomatoes, ready to be stewed

ready to begin cooking

After skinning and coring the tomatoes, toss them into a large pot, and start heating the pot on the stove.  There will be plenty of juice in the pot, so you don’t have to add any water.  Just heat it and mash up all the tomatoes until it is all one big pot of mush.

cooking tomatoes to make tomato juice and spaghetti sauce

stewing (cooking) the tomatoes

This is when you will decide what you’re going to do with your tomatoes, whether to make tomato paste, juice, relish, or some type of sauce.  As I said, we decided to make both tomato juice and spaghetti sauce.  If the two recipes will have the  same seasonings, add those seasonings at this point, before  you separate the juice from the sauce.

But we separated the juice from the sauce before doing that, before adding the seasonings.  Oh, well, now we know for next time. But we actually added mostly different seasonings to each.  So, we’re okay.


straining tomatoes through a sieve to separate juice from paste

straining to separate juice from tomato pieces

We poured the stewed tomatoes through a sieve to separate the juice from the tomato paste.  I prepared the tomato juice while Andrew worked on the spaghetti sauce, the job with more work.


For the tomato juice, I added some brown sugar, salt, celery salt (it would probably taste better with the actual celery stalks and leaves, but we didn’t have any), a very small bit of mashed garlic (which Andrew had mashed for his spaghetti sauce), and a few bits of chili.  Very little garlic and very little chili.  Now, you simply bring the juice to a boil, and then pour it into canning jars and seal them as usual.  (More on that “usual” bit later.)

tomato juice and spaghetti sauce

sauce and juice simmering

Meanwhile, Andrew cut up and friend one onion in a bit of canola oil.  To this he added his mashed garllic (he used our new mortar and pestle from GrabOne), pepper, and brown sugar, and LOTS of mushrooms.  (We later decided it was a bit too many shrooms, but if we didn’t put them into this sauce, they would probably have gone bad before we used them.)  He fried it all until everything was well mixed and cooked, then he added the sauce into the fry pan.  I thought that he would add the seasonings into the sauce pot, but I think he made the better choice.

This mix, he brought to a boil and then simmered awhile, to get the seasonings and tomatoes all flavoured together.  The best sauces are simmered for hours, but we didn’t really have that much time, since we began this project after Andrew got home from work on evening.  After it had simmered, and we had transferred the tomato juice to jars, we then canned (jarred) his sauce.

And here’s how you can/jar most anything.  There are many methods, and different methods in different countries, it seems.  The most popular method here in New Zealand seems to be what is called the “overflow method”.  With this method, you fill the jars to overflowing, be sure all the air is out, and then seal the tops, after which you either boil the full jars for up to an hour or toss them into the oven for awhile.  We’ve found that this “overflow method” is very messy and actually provides an opportunity for some little bit to get between the jar and the lid, thereby destroying the seal that is necessary.

So, what we do is wash the jars well, then sterlize them by setting them into hot, hot water.  And we leave the jars and lids in the water while we are finishing the cooking.  You never want to place hot food into a cold jar, as there is the possibility that the jar will crack from the sudden heat.  So, you need to have your jars be hot.  Many people here in New Zealand will heat their jars in the oven instead of with hot water.  Either way, you want sterile jars, because any organism can cause your yummy canned goodies to rot, causing gas, which in turn pops the seal on the jar.  And, as I said, you want the jars to be hot when you add hot food into them, as well, to keep them from cracking.

So, we drain our hot jars for a minute or two, and then simply pour the goodies (in this case, tomato juice and spaghetti sauce) into them, leaving a cm or so (half an inch) of space between the food and the top of the jar.  Then wipe the rim to be sure there is nothing that will come between the jar and the lid.  Even the smallest bit of food will break the seal.  You need the seal to be air tight, in order to preserve your food.  If the seal is not air tight, you’ll need to refrigerate the jar and eat it fairly soon, before the food goes bad.

After you’ve wiped the rim real good, place the hot lid in place, and screw tight.  You want the lid itself to be heated, as well as the jar, because the rubber on the lid, which is what provides the seal, will form to the jar top better if it is hot, or at least warm.  Then set your jars of yummies aside to cool.  Place them either on a wood cutting board or thick newspapers or cloth, so that the bottom doesn’t cool too quickly.

After a few hours, the food in the jars will cool and contract, thereby creating a vacuum inside the jar.  This vacuum is what causes the good seal on a jar.  If your lids are not pulled down slightly after the food has cooled, or if the center of the lid pops back up when you press down on it, that means there is not a good seal.  You will have to either heat the food back up and try again, or simply refrigerate or freeze the jar to eat sooner.

After the jars are completely cooled, you can remove the bands holding the lids to the jars, if you want to.  We mostly prefer to leave them on, for fear that moving the jars around (into to garage, out of the garage to the pantry, etc.) might dislodge the lids if the bands are not there holding them in place.  And the bands are not overly expensive.  And one last reason is that we have pretty much about as many bands as we have jars, so we don’t need the bands to seal other jars.

Altogether, including washing, peeling and coring, and cooking, the entire process from start to finish took about two hours.  When I make jam (or jelly), the process usually takes about three hours, probably because the preparation of fruit (plums, peaches, apples, feijoas) takes longer than the simple process of peeling and coring the tomatoes.

So, we have about half of our tomatoes all ripe and canned.  The other half will be coming ripe probably within a week or so, and we’ll likely do this same type of process again.  I think, though, that next time, I will skip the chili.  Even the little bit that I added makes the juice burn my throat.  And I’ll probably use slightly less brown sugar.  I like things VERY sweet, but this tomato juice might be just a tad bit too sweet for being tomato juice.


canned spaghetti sauce and tomato juice

finished products

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