Canning Tomato Sauce

by Frank

I'm italian, I eat a lot of pasta!

I'm italian, I eat a lot of pasta!

A few times a year I'll cook a 45 qt pot of tomato sauce just for canning. I use all quart jars. I cook the sauce for hours and make sure the temp is well over 200 degrees.

I wash all my quart jars and run them through my dishwasher on a very hot cycle right before I am going to fill them with the hot sauce. I add a little salt and lemon juice to each jar before filling. I usually try to remove some air bubbles before putting the lids and caps on.

My question is am I suppose to do a boiling water bath next? I never have and my sauces have lasted over a year with no problems. Maybe three or four out of about 50 quarts will have some mold when I take the lid off but that's probably because a lid didn't sit right.

The sauce is all for personal consumption. I just wonder if the boiling all the cans is a waste of time and not necessary for every type of canning. Seems redundant to boil the jars if t
he hot liquid I'm putting in them is already piping hot.

What are your thoughts. Thx. Frank


Hi Frank,

This is a tough question, because if you've been doing it this way with no problems you may say "what's the big fuss?" However, I have to still recommend processing your tomato sauce.

When you process the jars after they are filled and the lids placed, the jars and foods are sterilized. All spoiling factors are stopped. And the jar is sealed so the food will not be recontaminated.

The concern with not processing your tomato sauce is this.

1- Your jars are very clean but very clean is not sterilized.
2- You stated that you are sure to get your tomatoes to above 200 degrees. Botulism can only be killed at temperatures above 240 degrees.
3- Even if you believe your tomatoes have been sterilized by the cooking you have done. It is still exposed to the air and cooking utensils used to transfer it to your jars. I can be recontaminated in that short time.

So now you have food that is in the jars and sealed, but if the bacteria got into your food before it sealed you have a problem. And as you indicated you have seen mold on a few so you know that at least those few have been recontaminated even as careful as you can be.

Botulism is the main concern. Mold you can see and simply throw away. However, botulism can not be seen, or tasted, or smelled. You will not know it is there until you get sick. And it can be lethal.

IMHO You really should be processing in a water bath or a pressure canner.

I am glad to see you adding lemon juice, that acidifies your tomatoes which also deters botulism.

Here is another page about canning tomatoes and acidity levels.

I hope that this helps you make your decision.



Sharon, Thanks for the quick reply. Well, everything you pointed out makes very clear sense to me. I did boil my jars, lids and caps prior to canning. Also cooked my sauce to about 210 degrees.

But here is my question now. Is it too late to do the processing bath tomorrow on the jars that I've already canned. They would have sat overnight and cooled and I can hear all the lids popping which means they are sealing tight.

Do you see any problems with me doing the water bath the day after the canning. In the future I will do it as soon as I'm done canning and while the contents in the jars are hot.

Thanks, Frank


Hi again Frank,

Yes processing tomorrow is fine. As long as it is within 24 hours you will be ok. You'll need to reheat the contents as you don't want your jars to go into the canner cool. So unfortunately that means emptying the jars, heating the sauce and re-jarring with new lids.

Have a great evening.



Hi Sharon,

Thanks again for setting me straight on the proper method for processing my cooked tomato sauce. Moving forward I will always remember to process in the hot water bath to ensure killing any potential bacteria.

But this batch is staying the way it is. The thought of emptying out all the jars, re heating, new lids, etc. is a huge hassle and throwing out a days worth of work is not an option.

Like I mentioned earlier I've probably canned sauce like this at least three times in the past and have had decent luck. I guess I'll take my chances but in the future I'll always do a final water bath. Not sure if it helps at all but I will be reheating the canned contents to a very high heat prior to eating it.

Thanks for all your input, it was very helpful. I'm going to check out your website and get some other canning ideas.

I also do homemade grape jelly that is incredible. Thank you, Frank


Frank I am so glad I could help. And I don't blame you for not wanting to redo all that work. OR throw it away.

For low acid foods (veggies and meats) USDA recommends boiling for 10 minutes just prior to eating, as an extra safety precaution. I'd recommend you do that with your tomatoes.

And you know what?? I am jelly challenged. LOL I usually opt for easier jams. In fact I tried grape jelly for the first time this year and it did not set up. I'm going to try to reprocess it with more pectin. We'll see how it goes. If not we have some grape syrup. And I did get some grape jam made.


The batch of tomato sauce that I just canned ended up being 41 quarts. That will most likely last me quite awhile. I'm Italian so I eat a lot of pasta. I'll keep a close eye on it and discard anything that looks visibly spoiled. The rest I'll re heat very well prior to serving and hope for the best. I have a stomach of steel so I'm really not too worried about it.

The last time I canned grape jelly was over two years ago. I did about 50 pint jars. I don't do anything small. I put an add on craigslist looking for concord grapes and someone let me pick everything they had. I cooked them down to a perfect juice, added my pectin and sugar, topped them off with wax and they firmed up perfectly. Nothing like homemade jelly.

Thanks for all your advice. Talk to you soon, Frank

Comments for Canning Tomato Sauce

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A follow-up -
by: Anonymous

Not sure if we can get additional answers this way, but I stumbled on this page while wondering if I can can tomato sauce over 2 days? I make sauce much like Frank, but today I started late, and I need to simmer the sauce down for another few hours, and it's already 10pm - is it okay to refrigerate the sauce the way it is now, and then to finish it tomorrow evening? I saw your note about 24 hours, but wanted more detail - is that hard and fast? Is 36 or 48 ok, as long as the half-made sauce is refrigerated?


Hi Jennifer, yes absolutely you can refrigerate the sauce as it is and then can it tomorrow or even the next day as you have time.

You need to reheat the sauce, then jar it and process as usual.

This is assuming you have not already filled your jars. You would not want to try to refrigerate your jars and then process them cold tomorrow.

by: Marsha

Got green beans all ready, put in jars and canner.
Pressure in canner never would come up. I tried
about 3 times. Never have emptied those jars.

Do I need to throw them away or will dishwasher
take care of the botulism I know is in there now.
It's been over a year.


You are wise to be wary of eating those green beans.

What I would do is dispose of the green beans. Be sure that no animals or family pets can get at them. If botulism is present they can get sick too.

Then sterilize your jars. Here's how:

Place empty jars right side up on the rack in a boiling-water canner.

Fill the canner and jars with hot (not boiling) water to one inch above the tops of the jars.

Bring to a boil and boil 10 minutes.

Carefully remove hot, sterilized jars one at a time and drain.

They will be hot!

More on how to sterilize jars for canning.

bubbles in my jarred tomatoes
by: Anonymous

When I jarred my tomatoes and took them out of the water bath I see they have a lot of air bubbles is that ok?

Yes the air bubbles won't hurt. Be sure you canned them with the correct processing methods.

canning tomatoesl

I have a question about a jar not sealing.
by: Diana

I canned tomatoes and corn yesterday. It was late and after I canned the pints of corn I went to bed without hearing them all ping. When I checked today, I noticed they all sealed except for one. Seeing as they sat all night and this am the one not sealed is it safe to redo the one jar?
as long as you notice the unsealed jar within 24 hours it is ok to reprocess. Use the same proper procedures you used the first time.

Also, I did put water in the jars before processing, but notice it seems to only have the water part way up the jar. Is this ok?

Yes, sometimes the liquid gets pushed out of the jars. As long as you know you processed for long enough and at the right pressure it is fine

Re canning refrigerated tomato sauce
by: Jan

Hello, today is Wednesday, I canned 5 bushels of Romanel and San marzan tomatoes on Sunday.. (blanched, processed the seeds & skins), boiled down to a thick sauce 50is minutes and sealed in sterilized mason jars. -Those that did not seal I refrigerated the next day.
Knowing that it has been Sunday to Wednesday, is it too late to re-process the sauce and re-load new jars?

Well, this answer is too late for your situation but yes, as long as the sauce was refrigerated I'd go ahead and reprocess using proper procedures for canning tomato sauce.

In Regards to Spoiled Canned Foods
by: Anonymous

I would also like to mention that in addition to sterilizing jars, it is very important to de-toxify the contents as well, so that no animals or waste disposal workers get sick.

The Joy of Cooking (if you have it) has a good article on this topic, is clear to understand, and no-nonsense.

And this is from the National Center for Home Food Preservation

Safe Canning, everyone!

Half a jar
by: Deb

I have been canning sauce in quart jars for a very long time. Now with an empty nest I only need pints. My problem is I have tons of quart jars and only a few pints. My question is, can I process half filled quart jars of sauce?

No, you need the headspace to be correct in the jars so half filled jars would not work.

Jar lids popping before placed into hot bath
by: Sport

Hot tomatoes, hot jars, hot lids....waiting for water to boil in canner....and POP! POP!.....what the heck? I did not what to do? So I went ahead and put all of them into the canner. Followed process and wonder what was right?

Yes, Sport you did just right. Next time try to have the canner already hot when your jars are filled so they can go right in the canner. Good job!

by: Fhum

I read your answer regarding Botulism and how we should use a canner to process tomato sauce.

Last year I followed my husband and his grandfather's lead and they neither added lemon nor processed with a canner. I hadn't done my research last year- now I add 2 tablespoons of lemon juice to a litre of sauce therefore the pH enters the safe zone preventing the spore - found in soil- to produce the bacteria.

This said, how would contaminates from air or utensils change this? From my understanding the spores may be present and boiling does not kill them- but changing the pH prevents this from producing bacteria. Did you mean that the contamination with air and utensils provide problems other than botulism?

Also, would heating the sauce to 185F for 5min before consumption kill the botulism if ever the spores were to produce bacteria?
Thank you so much,
Signed- my husband is Italian and thinks its overkill since his family has been doing this for generations - and I'm a concerned doctor.

You really need to use tested methods for canning. Adding lemon juice if you are using a waterbath is what is recommended. Don't rely on the boiling after the fact.

As far as the debate with your husband.... no advice here. :) Just wishes for good luck.

New Canner w/ Botulism Fears!
by: Paige


I finally attempted to can my meat sauce following all directions and using a pressure canner. They sealed beautifully, I polished the jars and set them in my pantry with pride.

Now, I just look at them. As a Biology major I just wonder if they contain delicious sauce or eminent death from Botulism!

I am scared to consume them!

Is there any way to test food product for Botulism to ensure your methods are solid?

I am sure I sound crazy but I really want to learn how to do this with confidence...I am moving to a farm in less than a year. I just don't have and family/friends with experience!

Thanks so much!

Paige, I don't know of a method to test for botulism in your jars. However, I'm so glad to encourage you that as long as you are sure you followed the tested methods your meat should be fine. Enjoy it.

It is nice to encourage someone who is cautious!

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