Originally published November 22, 2013
The first time I canned tomatoes I was about 9 months pregnant. I got tomatoes ridiculously cheap at an Amish produce auction when we lived in the Midwest. I was eager to make quarts and quarts of spaghetti sauce because we use it all the time.
I ran the tomatoes through my strainer-saucer-juicer
It was the biggest waste of time and energy! I stuck to diced tomatoes after that.
That is, until I talked to my mother-in-law. She had probably called for a baby update, but I gave her a tomato update instead. I was worried that I wouldn’t get the 100+ pounds of tomatoes processed before the baby came. I was surprised and thrilled when she told me that I could freeze the tomatoes and puree them later. Really? I had never read anything about that before.
She explained to me how she cans tomato puree and then makes the sauce later. The processing time for tomatoes (time in the canner) is the same no matter what shape your tomatoes are in (whole, halves, diced, sauced, etc), so why not puree them now and make them into sauce later? I love my mother-in-law’s spaghetti sauce and I love time-savers (which this definitely is), so I was all ears.
For those who aren’t experienced canners, don’t worry! I will go through all the steps. You can totally do this!
1– Gather, Wash and Core Tomatoes
This step is pretty self-explanatory. Be sure to take out any bad spots or thick white areas around the core. Even if some of the tomatoes are getting wrinkly skin they will work fine. If you are going to freeze them, I recommend quartering them to make thawing and pureeing easier. Depending on your blender or food processor, you might want to quarter them anyway.
(1.5– Freeze Tomatoes)
This step is not necessary, but it helps to consolidate your canning efforts. I like to make one big canning mess in my kitchen and then clean it all up, as opposed to doing lots of small batches. Since I have room in my freezer I have this luxury. I freeze my tomatoes in gallon-sized freezer bags.
Let your tomatoes thaw overnight or at least for a couple hours before pureeing them.
2– Puree Tomatoes
One of the benefits of pureeing, as opposed to using whole, diced, or halved tomatoes, is that you don’t have to remove the skin! Ahh, life just became so much simpler.
I used to use my food processor. I have also used an ordinary blender. Now I exclusively use my Blendtec blender (I love that thing– it will even grind wheat!) Puree the tomatoes completely. This goes pretty quickly for fresh tomatoes, and takes more time for frozen tomatoes. In fact, if your tomatoes are still icy, you will get what looks like a pink tomato sherbet (since they will get lots of air mixed in from blending for that long).
The first image is frozen tomato puree and the second is fresh tomato puree.
3– Heat Tomato Puree
I always hot pack my tomato puree (hot liquid into hot jars). Just heat the tomatoes to boiling. Be careful that they don’t boil over!
4– Prepare Jars and Flat Lids
Jars should be cleaned in hot, soapy water, or in your dishwasher. Turn warm (not cold) jars upside down in an inch or two of boiling water. This step is to sterilize the jar and get it hot. I love that I can use the bottom of my steam canner to heat my jars. I used to just use a regular pan (see first picture), but the steamer holds seven jars at once (second picture)!
Put 7 flat lids in the boiling water as well. Heating them sterilizes them and helps to soften the rubber seal.
5– Fill Jars
Start by adding either bottled lemon juice (2 Tablespoons per quart, 1 Tablespoon per pint) or citric acid (1/2 teaspoon per quart or 1/4 teaspoon per pint). We use citric acid for homemade dishwasher soap, so I always have it on hand. The need for this varies depending on the acidity of your tomato variety and when they are harvested, but you definitely want to be better safe than sorry!
Using a canning funnel (err… mine was in the dishwasher when I did this batch) and a regular soup ladle, fill each jar, leaving about 1/2″ head space. If you used frozen tomatoes for your puree, you will notice there will be foam on top. Do your best to spoon off the foam. There is nothing wrong with foam and it will become normal liquid after canning it, but when all the bubbles from the foam disappear, the sealed jar will not be completely full.
6– Clean rims, put on flat lids and rings
The top rim of the jar needs to be clean and free from chips or cracks to get a good seal. Use a wet cloth to clean the rim. Using the handy magnetic lid lifter that comes in every canning tool kit (or with skilled hands you can use a fork), grab a flat lid out of the water and place it on a jar. Screw a band on tight, not overly tight, just tight.
7– Process
In a water bath canner
In a steam canner, you start timing once the steam coming out the hole is at least the length of a quart jar. You can turn the heat down (so it doesn’t steam like crazy) as long as you still have a steady stream of steam. When the time is up, turn the stove off. Remove the lid by lifting it away from you so you don’t get a face full of steam.
It’s normal for the puree to separate into liquid and pulp, so don’t fret.
8– Cool Jars, Remove Rings, Wash Jars
Using the jar lifter from your canning tools (or just a hot pad), move your jars to the counter. I usually set them on a towel. Let them cool overnight in a non-drafty area.
About 24 hours later, remove the rings, check the seal and wash the jars. To check the seal, pull up lightly on the flat lid with your finger. If it pulls off easily, the jar did not seal adequately. Stick the jar in the fridge and use it in the next week or so.
All the jars that sealed well can be stored for years in your pantry or any other relatively cool and dark location. Label them with the year and contents so that you can keep your food storage rotated.
Now you’re ready to make simple, quick and delicious spaghetti sauce using a jar of your own tomato puree.
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I have a 5 lb. ll oz. can of purchased Heinz, Bell’Orto, extra heavy tomato puree. Can I freeze small portions of it in freezer bags or plastic containers to use in receipes later? Or if not, can I recan it in small jars like I do with whole tomatos.
Absolutely! I do this with giant cans of pineapple all the time– just use what I need, then portion the rest out into freezer bags!
You did not mention anything about straining after you put the tomatoes through the blender. Surely you don’t include the skins in the canning process.
As long as your tomatoes are cleaned off the skins have nutrients and extra flavor. I can some with skins after cooking for about 30 minutes to an hour. As long as they are pureed to tinny bits. You can include them in the canning process and if you wish strain them later.
Important note: tomatoes are good heart food.
I just purchased some new canning jars and an insert in the package says “New and improved SureTight lids Helps keep canned food sealed now up to 18 months”. Just thought you might update your information on food keeping for years. I’d hate to think someone might put all that time and effort into canning just to find out their seals might not hold for more than 18 months.
Please read this from the University of Wisconsin Extension on Steam canners.
http://fyi.uwex.edu/safepreserving/2015/06/24/safe-preserving-using-an-atmospheric-steam-canner/
I considered using one, but after reading this decided my good old hot water bath canner was way simpler and, I feel, safer.
I freeze the tomatoes just like you do. Then I take them out of the freezer and slip the skins off them and let them continue to thaw. Then I run a knife over them on the cutting board, toss them into a pot and make spaghetti sauce. I never ever can them. There really is no need. Garden tomatoes make the tastiest sauce ever. I freeze them in the late fall or early fall and have them for the entire winter. Easy peasy.
You should always, always, always add lemon juice or citric acid to tomatoes before processing them in a hot-water bath. Otherwise, you might get botulism toxin in your tomatoes and kill yourself or your family. It happens every year somewhere in the country and I know I don’t want to be the cause of it at my house! Also, make sure you adjust the processing time based on the altitude of where you live. The higher the altitude, the longer you have to process in order to get the temperature up high enough. In Utah, you have to add 10 minutes. In Colorado, it’s about 12. In other places in the United States it will vary. The rule of thumb is 2 extra processing minutes for every 1000 feet you are above sea level. When in doubt, please consult your local extension office or a reliable modern canning recipe book. The old canning methods that worked for your grandmother do not work anymore because of the unreliable acidity in different hybrid tomato varieties.
Susanne is Very Correct on her statement!
I will note that if you use bottled lemon juice it works better because actual lemons are totally different than bottle. Also if you are getting ready to can and you have hot sterilized jars do not add the cold lemon juice to the hot jars they will Crack, add the juice to half filled jars, 2 tablespoons per quart and 1 tablespoon per pint.
Susanne sounds like an experienced canner!
I just started canning my fresh tomatoes this year from my first ever garden. It is such fun to can your own produce!! It is so worth it!
When we can we never do the hot bath after. It has always worked without that final step. Is this something I should be doing. Do you know the purpose of it? We have stewed tomatoes from a year ago that we are still eating and haven’t come across a bad batch yet. Just wondering.
Thank You. Very great lessons here.
ARIEL
Hi Ariel! It’s my understanding that tomatoes should ALWAYS be processed (the final canning step) to prevent botulism, which can be fatal! I know some people (like my grandma) never do the final step when canning jam, which is still not a good idea, but it’s safer than with tomatoes (because of all the sugar in jam). Botulism isn’t always obvious (with sight, smell, etc) but is very dangerous. I wouldn’t eat tomatoes that haven’t been canned properly.
Always process in a hot water bath, steam canner or (canning pressure cooker)! Short cuts in canning especially this process will make someone very sick unless you are freezing in freezer bags. Always label with dates.
Can you can tomatoes without a water bath or a steamer?
I boiled my jars and lids in steamer to seal the jar do you need to do the next step?
YES! You must process them for the correct amount of time to preserve them. Even if the jar “seals” on its own because the jars, lids and tomatoes are hot, that alone will not prevent botulism that could be deadly! It really is a big deal that you go all the way, especially with tomatoes!
Just wondering – maybe this is old school but I was under the impression you have to add lemon juice or something acidic to tomatoes due to botulism. I have avoided canning tomatoes because of this and fearing making us sick. Do you know if that is not the case anymore or this specific way you do it?
Hi Liz. That’s a good question. While tomatoes are acidic, some new varieties of tomatoes aren’t acidic enough (pH is supposed 4.6 or less to be safe). I’ve done it both ways. When I first learned to can tomatoes (whole or diced) I learned to put lemon juice in. My mother-in-law never does it. Many people who have been canning for ages don’t do it.
If you want to be certain, go ahead and add in lemon juice. It won’t hurt and it will bring you peace of mind. For quarts add 2 Tablespoons of lemon juice or 1/2 teaspoon of citric acid (for pints use half of that). There’s nothing wrong with playing it safe! 🙂
Canning is scary even for experienced canner. Yes bottled lemon juice or canning citric always, see above notes: 2 tablespoons per quarts lemon juice and 1 tablespoon per pints lemon juice.
Good luck once you get past the fears and nerves it pays off.
I will add before putting on the seals run a butter knife or long thin spatula are the jars slow to release air and only tighten jars by finger tips secure but not tight because some air or juice may release during processing.
See all the above notes they are helpful.
Meant butter knife around the inside of the jar slowly to release air.
I’m a newbie to canning, and very excited about all the possibilities. Thanks for posting this simple recipe! How many tomatoes do you start out with for one batch (7 jars)?
So I’m a number of months late commenting on this :)……
I tried this this morning when the 6 gallon bags of tomatoes I still had in the freezer from last summer’s garden. So I did know you could freeze tomatoes. Typically, I thaw them, cook them down some, run them through a food mill, then finish cooking down to sauce. I don’t add the spices before I can as sometimes I only need plain sauce, sometimes pasta sauce, sometimes pizza sauce, etc.
I found this method with the food processor more work than what I normally do. Either my food processor isn’t great or I’m doing something wrong but I had to push all the puree through a mesh strainer to get rid of the seeds. I was hoping this would just pulverized the seeds to the point they weren’t even noticeable but that wasn’t the case for me. Do you not have issues with seeds in your sauce?
Hi Julie! We don’t have issues with seeds. There are seeds that aren’t pulverized in the food processor, but we don’t ever notice them. I guess if you are bothered by seeds and want them all out, then using the strainer/sauce maker (we use this one
) would be worth it. For us it takes more time and requires more of a set-up/clean-up to do it that way, so we prefer using the blender or food processor. I’m sure our Blendtec blender would pulverize the seeds. It takes care of blackberry seeds. I’ll have to try it this year (we just got it in December).
I guess my food processor just isn’t tough enough. I have a Black and Decker one that works for everything else but didn’t pulverize any of the seeds. I don’t mind a few but all of my seeds were left whole. Good to know it wasn’t just me doing something strange though. 🙂
Guess I’ll just stick with my old way of using the food mill. So much faster than trying to do it with the food processor and a strainer. Worth a shot to try something that some find faster and easier though, just didn’t work for me. 🙂
I guess we are just used to the seeds and it doesn’t bother anyone. I figure when you eat tomatoes whole or in salads you eat the seeds without batting an eye, so we don’t mind having seed in our sauce or soup. Thanks for sharing your experience!
Weston tomato press works great and separates the seeds well. But need to run tomato parts through the press 3-4 times or you miss lots of juice. Excellent for apples too.
Can you tell me….is there any particular temp requirements for canned items? I would love to can, but the only place I would have to store them would be in my garage which can get pretty warm in the summer. It is attached, but not heated or cooled. Any thoughts on that? Thanks so much for the how to. I have wanted to can for years but haven’t a clue where to start or where to store the stuff. Thank you!
It’s best to store the jars somewhere cool and dark. The temperature change in the garage probably isn’t a good long-term idea. In our old house, we used to have a mudroom that led to the garage (but still in the house) that had nice deep shelves.What about in boxes under your bed? Could you trade some closet space for the garage space (put something from a closet into the garage, then store canned food in boxes in the closet)? I bet you could make it work somehow.
We have pretty limited space right now (we live in my in-laws’ basement), so we have all of our bottled food in boxes stacked along the wall of our kids’ bedroom (like 6-7 boxes high). We use boxes that are just the right size for a dozen jars and fit nicely on top of each other. We also have the space under my daughter’s twin bed filled with boxes of jars.
Such a treat to be able to enjoy your own tomatoes during the winter months! thank you for sharing on the HomeAcre Hop. Hope to see you again tomorrow!
Nancy The HomeAcre Hop
I’m a new reader to your blog and love the easy food storage ideas! I always put off tomato canning but this method seems pretty painless. Hoping for a better tomato year next year to give it a try!
Welcome Molly! It really is easy! I think it took me less time to do 3 batches (21 quarts) of tomato puree than it did to do tomatoes for four jars of salsa where the tomatoes have to be peeled and diced. Good luck with next year’s tomatoes!
I looooove tomatoes – this looks great! It’s so much better than letting anything go to waste.
Yes! Freezing the tomatoes makes it convenient to do the canning anytime.
Great and healthier alternative to store bought jars! Definitely going to try this out! I love how thorough your ‘howto’ posts are Stephanie!
Thanks Moneycone! It’s definitely healthier than the canned stuff from the store 🙂