Canning Tomato Sauce

with Sharon Peterson

When I am canning tomato sauce, I use Roma tomatoes. Meatier tomatoes like the Roma tomato will give a thicker sauce. Juicier tomatoes will have to be cooked down more to thicken.

Canning Tomato Sauce is easy with these options, tips, and tricks!

Wash tomatoes and remove stems and bruised portions.

You'll need to remove skins. 

Removing seeds is optional. When I'm canning tomato sauce, seeds don't bother me for things like spaghetti sauce or stews and chili. But I would not want seeds in something with a smoother consistency like ketchup or tomato soup. Depending on what your use is for the sauce, you may leave the seeds if you like. 

I've described three ways to prepare your tomatoes for canning. The method you choose will depend on how you want to preserve it.  

  1. Option one - Use a blancher to remove skins but not seeds.  
  2. Option two - Use a food mill, which will remove both seeds and skins.
  3. Option three - Use a blender, which does not remove either skins or seeds.  

I'll explain the options. Then continue at the bottom for ideas of how to use your tomato sauce, or if you want to can it up just like it is without seasoning, I give full canning instructions below as well.  

Option One: Blanching to Remove the Skins.

Tomatoes in basket.

This option will remove the skins but not the seeds. 

This is easiest done in a blancher. If you don't have one, you can just use a slotted spoon and a big pot of boiling water. 

Blanch 4 to 6 (or more if small) tomatoes at a time. This will always depend on the size of the tomato. In the example pictures, I am doing Roma tomatoes. I like them for canning because they are meatier than other tomatoes. They are smaller too, so I can fit more in the blancher. 

  1. Wash tomatoes and dip in boiling water for 30-60 seconds or until skins split. You will often see the skins separating. 
  2. When you remove the tomatoes, drop them immediately into sink or bowl of cold water to stop the cooking.
  3. Slip off skins and quarter tomatoes. The skins should just slide off in your hands. (Occasionally, I'll use a knife on some stubborn spots.)
Tomatoes with skins slipping off.
Peeling skin.

Tip - I like to have two pots set up in my double sink. The one on the left is for the cold water to cool the tomatoes as they come out of the blancher. The one on the right is to slide the skins off into. The pots are lower than if you set them on a counter, which is easier on the arms, while the sink makes for easy clean up. 

As you skin the tomatoes, slice them into a pot where they will be simmered. 

Option 2: Skinning and Peeling Tomatoes with a Food Mill.  

Another way of preparing your tomatoes for canning is to use a food mill. This is my preferred method. The food mill removes both the skins and the seeds.  

First, wash your tomatoes in cold water, and then slice in half. Simmer the tomatoes to make them softer for the food mill. 

Halved tomatoes.
Simmering tomatoes in pot.
Going through food mill.

It is easier to do this if you have some juice in your pan to start, so try this: Place a single layer of tomatoes in a pot. As it heats, use a potato masher to crush tomatoes to draw out the juices. When you have a bit of juice in your pot, continue slicing tomatoes in half and adding to the pot. 

When all tomatoes are sliced, simmer for 15 to 20 minutes or until tomatoes are juicy and heated through. 

I used two large pots to simmer 30 pounds of tomatoes. With the tomatoes split into 2 groups, it is less likely to scorch. 

Put tomatoes through the food mill. This removes all skin and seeds. 

Option 3: Use a Blender to Liquefy the Tomatoes for Sauce.


This option does not remove the skins or the seeds. I'll use this on occasion when I'm in a hurry to take care of lots of tomatoes.  

Keep in mind that all "official" tested recipes do state to peel the tomato first. In my opinion... and I'll repeat that it is my opinion, this is a quality issue. The peels may be unappealing to some people. 

However, there are those who say that it is a safer thing to be sure and eliminate the peels first. This is an area where you need to make your own decision. I'll give you the information I have... and you get to decide!  :)  

The method is pretty self-explanatory. Just wash your tomatoes, remove any stems, plop them in the blender and blend until smooth. Just long enough to get them all soft and saucy. Work in batches a few at a time until all tomatoes are finished.

I do this step with the tomatoes raw. I suppose you could simmer your tomatoes first, but be very cautious about hot liquid spitting out of the blender and burning you.  

Canning Tomato Sauce Instructions. 

Now you are ready for canning tomato sauce. You can use it in recipes like stewed tomatoes or spaghetti sauce if you want. Canning tomato sauce unseasoned is a great idea. It is very easy to use for many recipes when you are ready to cook supper.  

Try this time-saving canning tomato sauce tip. Another reason I love the food mill method.

Favorite Canning Tomatoes Tip.Link to handy canning tomato sauce tip!

First, bring the tomatoes to a boil. Use a medium heat, stirring often to prevent burning. If you had especially meaty tomatoes and your sauce is thick, you may need to just stand there and stir.  

It can be canned just as soon as it is hot and bubbly. IF you would like to have a thicker sauce, you can cook it down. Simmer, uncovered, to thicken. Cook until it reaches your desired consistency. Stir frequently to avoid burning! The amount of canned tomato sauce may be reduced by nearly one-half. 

An easy way to do this is to place sauce in a slow cooker and leave the lid off. Let it cook until thickened.

Preparation Information

Gather your canning supplies:


  • 30 pounds tomatoes
  • bottled lemon juice
  • salt if desired

What's All This About Lemon Juice?

Canning Tomatoes with Lemon Juice?

For more information on why acidifying your tomatoes is important, please read...

Canning Tomatoes Safely you really need lemon juice? 

To process the sauce just as is: Fill hot jars. Add 1 T lemon juice to pint jars and 2 T lemon juice to quart jars. Leave a 1-inch headspace. 

My suggestions is to follow pressure canning instructions. This is my preferred method and is what I've included below.  

Be sure and adjust your processing to your altitude. 

Processing Time

Be sure you are using the correct time with the correct method. Double check... water bath? Or pressure canning? And be sure to use the instructions for your altitude.  

For more information on why this is important, see this altitude adjustments page.

Pressure Canner Processing Directions

Process Pressure Canner

Pints - 15 minutes.

Quarts - 20 minutes.

Adjustments for Pressure Canner
Altitude in Feet Dial Gauge Canner Weighted Gauge Canner
0-1000 11 10
1001-2000 11 15
2001-4000 12 15
4001-6000 13 15
6001-8000 14 15
8000-10,000 15 15

Water Bath Canner Processing Directions

Process Water Bath Canner 

Altitude in Feet - Processing time in minutes

1-1000 - pints 35, quarts 40.

1001-3000 - pints 40, quarts 45.

3001-6000 - pints 45, quarts 50.

6001-higher - pints 50, quarts 55.


More on Canning Tomatoes

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by Sharon Peterson, Copyright © 2009-2019

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Any statements or claims about the possible health benefits conferred by any foods have not been evaluated by the Food & Drug Administration and are not intended to diagnose, treat, cure or prevent any disease. You are encouraged to verify all canning and food preservation advice on the USDA food preservation website. 

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