What exactly do you mean by that? Why do you not process for the longest ingredient? The reason I'm asking is because there was a discussion about the quote on a facebook canning group and people were wondering.

Thanks for your time.

Pressure Canning Green Chile Sauce

So I guess I begin by saying that I am far from the only person that makes that statement, here or elsewhere. Most experienced home canners that make the effort to remain current with the guidelines know it, And anyone who has ever taken a certified canning course has certainly heard it.

Although "process for the time of the longest ingredient" was mentioned in some older books and while it is true that many recipes that include meat call for the meat processing times, not all do, it was never an official guideline.

It is simply an assumption made by long ago home canners that took on a life of its own. They noted that 90 min was the max time called for (except seafoods) so assumed that time would be good for anything. They reasoned that if X mins was good then XX minutes was even better. They used that assumption to allow them to make whatever changes they wanted to in the recipe. The greatly flawed "Gee, I can safely can anything I want to if I pressure can it long enough" assumption was the result and is still used by many today simply to justify disregarding the guidelines and making up their own recipes.

But all this was before the role of pH and density in canning were understood and when the resulting quality of the food was of little concern. Those issues should have put an end to the old assumption but didn't unfortunately.

So it is "guess work" because it encourages the canner to make up their own recipes and processing times and it disregards both pH and density of the mixed ingredients and the end quality. Tested recipes instead test to balance safety AND quality.

Good examples are in the NCHFP FAQs that address the "why can't I can my own recipe for ______" questions.

These are low-acid mixtures which could support the growth of bacteria that cause botulism, so a process cannot be estimated or made up. It must be a tested process known to kill these bacteria in this product.

Still it all boils down to personal choice, personal risk. Those that regularly advocate "time required for the longest ingredient" works are almost always doing it just to justify canning their own made-up recipes. That is their choice, their risk to take.

Hope this helps clarify.

Dave

Too bad b/c some recipes sound good (braised brisket has meat, vinegar, tomato paste, brown sugar, onions and garlic) but now I'm leery of all of them. What's worse, there's just enough mention of current USDA guidelines that an inexperienced canner may assume all recipes in the book are safe.

I think a lot of people are not aware that pH is not the only concern. Density affects heat penetration, and a very dense mixture might actually require a longer processing time than that called for with a single ingredient like beef which might be processed in cubes surrounded by broth.

Water activity is also a factor as botulism spores, for instance, require a low-acid, high water-activity, anaerobic environment. That proved to be an issue with pumpkin puree, which is no longer recommended for canning. Moisture levels in home-grown pumpkin were all over the chart and the pH of the samples tested varied so much it was impossible to come up with a reliable processing time which also yielded a quality product.

Canning may not be rocket science, but it is science and the opportunities for something to go awry are limitless.

Carol

-- The toxins/spores produce by the bacteria can are fatal.

-- There has been 120 to 150 total cases of botulism reported ANNUALLY in US, of which 15% is food related (canning etc). That is 18 to 23 cases, in ALL USA in the course of one year. And from those not all of are caused by improper canning. .

-- It is the toxin/spores produced by the bacteria that is fatal , not the bacteria itself directly.

---Any food containing the spores/toxins boiled for 10 minutes or longer will destroy the toxin.

-- Any food item cooked at 250F( PC) will kill both the bacteria and the toxins, in just 3 minute. This means that the remotest part of food in the can MUST reach 250F and kept there for a minimum of 3 minutes.

Amazing. You make it sound so very simple. Simple but so wrong!!

That sort of gross over-simplification of the whole process is what misleads the under-informed into making dangerous assumptions about what is safe to do and what isn't.

Dave

I have said before many many times that the CDC categorizes botulism as low-frequency high-risk. There's nothing new in that.

It's not that it occurs often; it's that when it occurs the consequences can be dire (though not necessarily fatal). But each home food processor decides the level of risk they are comfortable with.

I do agree that an untested canning recipe is not necessarily unsafe. It is an unknown. It is equally erroneous to consider it either safe or unsafe but considerably less risky to operate on the assumption it's the latter.

Carol

Sure , I don't like to be one of the "one in 10,000,000" who dies of food related botulism but then I drive on the highways that tens of thousands die each year in traffic accidents.