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How To Tuesday - Canning Tomatoes With a Pressure Cooker

19/8/2014

2 Comments

 
As I said yesterday I have found that canning straight tomatoes is
the most versatile way I have found to preserve our  tomato harvest. These can
then be made into sauce, paste, puree or stewed.  I process these in the
pressure cooker as that is the safest way for me.

There are ways to process tomatoes in a water bath by adding lemon
juice or citric acid. Lemon juice can affect the taste while I have not found
that citric acid affects the taste. The decision is yours, by adding a mild acid to each jar, you can lower the pH enough to be sure your tomatoes are safe providing you follow the normal processing directions. However, as I said yesterday, we are trying to reduce our reliance on deep freezers, so things that I used to freeze, sauces, broth, and some meat is now being canned and for these you absolutely need a pressure canner. You are messing with botulism, it is odourless and tasteless and it can kill you. Enough said.

So preparing tomatoes for canning. There are as many ways to do
this as there people reading this. For my preserves I choose to simply use whole tomatoes. It is recommended to skin the tomatoes, now you can use a vegetable  peeler and try to peel your tomatoes, or you can freeze your whole tomatoes after cleaning them and cutting off any blemishes.

Freezing the tomatoes does two important things for you;  first it
will make the skins slip right off the fruit. Secondly and probably more
importantly it will remove, a large portion of the water in the tomato. This
allows you to use the glut of less meaty tomatoes, what my grandmother use to
call slicing tomatoes. The usual problem with using these tomatoes is that it
takes so much energy and time to boil off the water. Probably the best thing about freezing the tomatoes is that you can stockpile them until you have enough to make preserves with no loss in quality.
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Water from 2 tomatoes frozen for 2 days.
They are now very easy to peel, the skins just rub off. You can also remove the skins by blanching your tomatoes, dropping them in boiling water for approximately 15 seconds and then putting them in ice water.
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If you want to remove the seeds you can put the pulp through a food mill at this stage. I don't remove the seeds, I eat the seeds when I eat fresh tomatoes so I don't worry about them in my canned tomatoes.

It takes a surprising amount of tomatoes to make tomato sauce. In my experience it takes approximately 5 1/2 pounds of tomatoes to make 1 litre of thin sauce, and closer to 7 lbs for a really thick sauce. My regular tomato preserves are the consistency of a thin sauce. Depending on what I am using it for I can reduce it some after I open.

Now that you have  lots of your peeled tomatoes, put them in your stock pot and bring to boil, add 1 tablespoon of brown sugar and 1/4 teaspoon of salt  for each pound of tomatoes you put in. This helps to really bring out the flavour. Once the tomatoes have reached boiling, turn down the heat and continue to simmer until the amount has been reduced by one third, (for thick sauce reduce by 1/2).

While the sauce is simmering, prepare your supplies as you would for any other canning project, sterilize the jars and lids. If you are using lemon juice or citric acid get these ready and prepare for water bath processing. The amount of lemon juice for 1 litre jars is 2 tablespoons, for 500ml jars is 1 tablespoon. If using citric acid, use 1/2 teaspoon for 1 litre and 1/4 teaspoon for 500 ml jars.

The pressure cooker.
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Essentially a pressure cooker is a heavy pot with a lid that seals and a
valve that controls the steam pressure inside. It increases the pressure inside
the pot relative to the atmospheric pressure outside of the pot. For cooking
food, this decreases the amount of cooking time; for canning it increases the
temperature of the water and steam inside. In regular water bath canning the
water boils at 100 degrees C, no matter how much more heat you put under that pot the water will not get any hotter than 100 C, (212 F).
 A pressure cooker allows steam to build up inside the pot increasing the pressure and the temperature inside the pot. By just increasing the pressure to 15 psi, you will raise the temperature inside the pot to something close to 120 C, (250 F).  This is hot enough to kill any pathogens which are in your preserves. For cooking this means tenderising and cooking a 2 pound beef roast in less than an hour, and if you add beef broth and mushrooms you will be a pressure cooker convert.

 While features may vary from model to model, all modern pressure cookers
will have a lockable lid usually via a spring mechanism within the handle, a
sealing ring, a pressure regulator vent pipe and a safety release plate or
valve. Please read the manual that came with your cooker to become familiar with the model you have. The manual will also give you instructions for care and  maintenance of your cooker. It is important to inspect the seal and safety release valves or plates each time you use your cooker. For those of you who are somewhat intimidated by the idea of the pressure cooker, as I was, try setting up the cooker and just putting water in, bringing it up to temperature and then letting it sit. It will give you the confidence of  knowing it wont blow up, without all the hectic distraction of canning at the same time.

So that is pressure cookers 101. Somewhat intimidating but you just need to become familiar with them. Sort of like milking a goat for the first time, or operating a rototiller. Scary at first but we are all homesteaders here! We didn't choose to live this lifestyle because we hate learning new things. Now back to the tomatoes....

Once you have reduced your tomatoes to the level you desire, fill your jars and place the lids on, you do everything as you would for water bath canning, so do not over tighten the rings on the jars. Now you will have to put water in your cooker, the amount will vary depending on the size of your pressure cooker. Unlike a water bath you will not need enough water to cover your jars. In a pressure cooker it is the steam that does most of the heating. usually an inch to two inches of water is the recommended amount, but please check the directions that came with your cooker.

Place the jars into your cooker and lock the lid in place. turn on the heat and wait. Start timing once steam starts coming from the cooker, 10 - 15 minutes is the recommended time frame. Once the time is up, remove the cooker from the heat and leave it alone, do not try and remove the lid from a hot pressure cooker. Some models will have a pressure valve that allows you to manually vent pressure, if yours does you can release steam and then open.  Remove the jars and let them cool.

Picture
Sauce I made for my daughter, she uses it for pasta and prefers to have peppers and herbs added, hence the green.
So that's it You have now made tomtao preserves... with a pressure cooker! These will safely keep for 2 years, but if your house is anything like mine they will dissapear long before that deadline. Try experimenting with different recipes, you will find sop many ways to utelise these tomatoes.

 As always I'm happy to answer any questions. Have a great day everyone.
2 Comments
Rosz
28/9/2014 12:01:10 pm

Thank you so much for sharing about canning and about presure canning. I've always done water bath canning but last year we bought a large canner and did beef stew ( we have our own beef cows) and Bolognese sauce. Although my sauce tasted good, it was much tastier before being pressure canned because I had already cooked it down all the way so much of the flavor cooked out. I will try again this year, soon I hope. I would rather go into my pantry a get sauce already made then to get tomatoes to make it. But maybe in the future I will do that too, you made it sound pretty easy and quick. Thanks again

Reply
Shelli
28/9/2014 02:55:44 pm

Hi Rosz
I'm glad you found this helpful. I did the same thing when I started using the pressure cooker; cooked everything to perfection and then proceeded to turn everything to mush in the canner! (Some lessons are harder than others)
Now I really can't imagine getting along without it. Especially as we are trying to cut down our reliance on the deep freezers. I make and can everything from baked beans and chili to peaches in syrup.
I like the plain tomatoes simply because I can add fresh herbs and seasonings.and make pizza or marinara sauce or paella but what works for one person doesn't work for another!
Thanks for your comment, it is so nice to know I am reaching real people, not just endless spam bots. Give a few bottles of tomatoes a try; I usually just put them in the slow cooker in the morning with fresh herbs and set the slow cooker to either low or simply warm. It just depends how much liquid there is to reduce.

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    A  4-H Family
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    Hi! I'm Shelli Killen,
    a homesteading, homeschooling, wife and mother of five. 

    I am a student  herbalist with a passion for learning and a  habit of bringing home strays.

    I love music, and the power of creating things with my hands.
     
    I tend to do best when life around me is organized chaos
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