I've read in countless places that it is dangerous to can homemade soups that contain milk, cream, butter, oil, etc. What I can't seem to find out is why - does anyone know the reason for this?

Most of my soups are basically the same variation on a creamed soup, sometimes containing milk and sometimes not. I sautee the onions, add whatever veggies (summer squash, zucchini, carrots, leeks), then add potatoes and veggie stock, boil it all until it's soft, and blend it. If it's too thick I'll add some more stock or some milk. It generally turns out to be thinner than something like spaghetti sauce, but not as thin as storebought cream soup, because of the potatoes.

Anyway...I just got a pressure canner, and want to know if it would be safe to can this kind of soup, if I should just freeze it like I always have, or if I should alter the recipe in order to can it safely.

Thanks!

But I'd approach it from another angle. Adding dairy to canned soups, assuming you could do it 1) takes up more space (more bulk=more jars=more processing time and increased storage needs) 2) in all likelihood would result in compromised flavor due to the high temperatures. I don't like commercially canned milk or ultra-pasteurized products and doubt it'd be any more appealing in a home-canned product.

You can certainly process vegetarian soups and it's very simple to add fresh milk when heating, so to me personally the greatest benefit lies in not adding it when canning.

The UGA National Center for Home Food Preservation provides basic information on canning of soups that you might find helpful. Then, if you have a specific recipe in mind but aren't sure about times, procedures, etc. just ask away. There are lots of people here glad to help.

Carol

Dairy products contain fat which insulate botulism spores from heat.

Canning with dairy is a dangerous practice.

Carol

The reason: The fats in oil and dairy products encapsulates any bacteria in the product including botulism and this encapsulation prevents the heat used in the canning process from killing the bacteria.

The soup canning link Carol provided above provides precise instructions for those soups that are safe to can with this proviso:

Caution: Do not add noodles or other pasta, rice, flour, cream, milk or other thickening agents to home canned soups. If dried beans or peas are used, they must be fully re-hydrated first.

Be safe in your canning.

Dave

I pretty much use the chowder to use up small portions of the fish/chicken so nothing goes to waste. I can this in pint jars because by the time I add the milk, cheese and leftovers, I've got almost a full quart jar which is plenty for me and DH.

My plan was then to can the rest, so I could enjoy a treat once a week or so. The milk separated, and the whole thing looks terrible. I haven't just tried eating it, or seeing how it tastes. Maybe I can still salvage it by pouring off the liquid and adding fresh cream when I heat it up.

As for the bacteria, I used the 20 psi weight, and processed the batches for over an hour, so I'm pretty certain most of the bacteria, even botulism, must be dead. While fat may encapsulate the bacteria, at some point everything in the canning jar, food, fat, and bacteria, reach about 260 degrees F, with that 20 psi weight, and I'm pretty sure even this encapsulated bacteria feels the heat, and dies.

Salvageable? Possibly. Safe? Possibly not. It's your choice of course but I would toss it due to the risk.

Had you frozen it when made there would be no problem.

Dave

The problems with botulism are that it's undetectable, it affects people regardless of health status (some studies show a greater risk for healthy people than old/sick), and it's really bad (you could end up fully paralyzed but fully conscious on a ventilator for weeks). It's the only food bug that I think is never worth the risk.

You could try to salvage the soup by boiling it at a full boil for 10 minutes, but even then I'd be worried. An hour is about the regular time for canning soups, and if it's thick you probably weren't getting the most even heat penetration (which occurs mostly by convection in canned products). Plus the canning probably ruined the texture.

I'd continue to think of it as an expensive mistake, throw it away unopened (for the potential gross factor since it's separated), and as a consolation prize I'd treat myself to the ingredients required to make a new batch. And some good beer for the comfort that's in it.

Melissa

Yes, I swear, I have a 20 PSI weight that came with my Mirro pressure canner. It came with a 10, a 15, and a 20 PSI weight. I found a boiling point table online and found that 20 PSI above ambient atmospheric pressure results in a boiling point of 260 degrees F, far above the "recommended minimum" for killing bacteria.

Even on its' website, the Mayo Clinic says to can foods at 250 F for 30 minutes to kill botulism, and I exceeded that by over double. The 'Medicine.net' website says "Because botulism neurotoxin is destroyed by high temperatures (85 degrees C for five minutes)," .. again I am way over the deadly point in my canning, but I do appreciate the comment about boiling the stuff one more time before trying it.

As it happens, I am an inspector at Health Canada, though not under the Food & Drugs Bureau. I also have some connections with our CFIA (Canadian Food Inspection Agency). Although their main dealings are with commercially prepared foods sold at grocery stores, I'll see if I can arrange to drop off a couple of jars to them, to get a bacteria count, to satisfy both my own curiosity, and to be able to post some intelligent results here.

Meantime, I will ponder the situation, and, as Melissa so wisely suggested, do so over a cold pint or two. I like the way you think, girl. :)

Given the time of year, I highly recommend you look for either Buffalo Bill's Orange Blossom Cream Ale or a maibock (malty spring beer). My local brewery (Legend in Richmond VA) has their maibock for about 2 weeks every spring. I had two pints today and have to get back there at least twice in the next week to get my fill till next year. They bottle most of their beers but not this one, and it's my favorite beer ever.

Melissa

You can make it with the butter if you wish and freeze it and still be safe but it wouldn't meet the safe canning guidelines. Best I could offer (not approved - just a suggestion) is to fry the vegetables in a minimal amount of oil rather than butter and then drain them well to remove most all the oil before adding to the soup mix.

As with all mixed vegetable soups it would have to be pressure canned and would have to meet the 1/2 and 1/2 rule (1/2 the jars vegetables and 1/2 the jar liquid).

Dave