Adding thickener to your home canned soups before canning is typically a no-no because it raises density issues which in turn raise safety issues.
That means no flour, no grains (whole or ground), no dairy.
There are, though, three approved ways in which you can safely thicken the soups that you make for canning as per the USDA soup guidelines. Or rather, three approved ingredients you can use which will have the effect of thickening your soups somewhat.
- Potato;
- Beans;
- Okra.
Both potato and beans release a lot of starch during processing, which helps to naturally thicken your USDA Soup Guideline soups.
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Our current favourite way of thickening a jar of soup is after we open it. Just stir in ⅓ cup of SOS mix, then zap the soup in microwave as you would anyway to heat it: instant thick delicious soup. So make yourself some SOS mix!
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Okra is an ingredient that most people never think of adding to soups, but besides being a great ingredient in its own right, it also acts as a natural thickener to liquids.
It gives your soup a velvety richness, and adds “mouth-feel.”
And yes, it’s fine to put okra in your home canned soups as per the USDA soup guidelines. Kacey Christian at the National Center for Home Food Preservation wrote,
According to our recommendations for Canning Soup, okra can be used as an ingredient. The first step of the soup procedure is: ‘Select, wash, and prepare vegetables, meat and seafoods as described for the specific foods.’ … and we do have recommendations for Canning Okra . So you would follow the procedure for preparing okra for canning before adding it to the soup: ‘Wash pods and trim ends. Leave whole or cut into 1-inch pieces. Cover with hot water in a saucepan, boil 2 minutes and drain.’ ” [1] Christian, Kacey. If you haven’t stored your pressure canner for the season. Blog post by National Center for Home Food Preservation. 23 January 2013.
Bags of frozen okra are great to have on hand to toss into your soup mixtures to be canned. Just thaw them, then follow Kacey’s directions to “… cover with hot water in a saucepan, boil 2 minutes and drain” and then add them to your soup pot, then can.
Thickening your soup with okra is also a smart move calorie wise, as it adds very few calories.
For two naturally thick soups that are fine to can because they have been separately lab tested, see Carrot and Fennel Soup and Pea Soup.
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Celia Johnson
Can you thicken home canned with corn starch before you process it? Thx!!!
Healthy Canning
No.
Patty
I’ve known canners to add about a tablespoon of dried potato flakes before canning their soups, without any problems. Is this safe?
Healthy Canning
Why not do it upon opening and while reheating? They dissolve instantly, after all.
James Manley
Why is it safe to pack raw salmon
In a half or pint jar and pressure cook
For for the specified time at 10 lbs
And yet it is not safe to thicken
Soup by useing sure jel or other
Thickening agents?
Healthy Canning
Hi James, the answer is: testing. Lab testing arrived at processing times for the salmon whereby every micron of the jar would reach the botulism kill temperature in a specified amount of time. Lab testing also revealed issues with arriving at the botulism kill temperature in jars with thickening agents in them. Specifically, they found that starch molecules were helping to shelter botulism spores from the killing heat. In theory, it would be absolutely possible for someone to develop specific soup recipes where that was assured. But so far, neither Ball nor Bernardin has stepped up to the plate (Ball doesn’t do a lot with Clearjel, anyway), and the teeny little branch of the USDA that deals with home canning hasn’t had the budget. They do well to flick the light switch and find the lights coming on in the morning.
In the meantime, thankfully it’s super easy to open a quart jar of soup, slop it into one of those big pyrex 8 cup measuring jugs, stir in a tbsp or two of cornstarch in 10 seconds, then zap in microwave to reheat and as the soup heats anyway, it also thickens.
So in short, that’s the answer: lab-testing. Revealed that one (salmon) was a-okay, and the other, had issues. You’re right though in thinking we probably would have guessed the opposite if we didn’t know in advance.