How do I determine what's able to be canned?

[Pilori]

I've recently started canning things like beets and pickles, but I've only been following recipes from books like "The Joy of Canning". Now I'd like to try developing some recipes, but I've run into the issue of not knowing whether a recipe is suitable for canning (i.e. acid/sugar content is high enough) or the processing time in a boiling water bath. Example...I'd like to can the follow basic recipe, but don't know if the proportions of acid + sugar + salt are safe nor do I know the processing time:

4 cups thinly sliced unpeeled cucumbers

2 cups sugar

1 medium onion, thinly sliced into rings

1½ cups white vinegar

1 Tbsp kosher salt

1 Tbsp mustard seed

So, I guess my question is how can I develop safe recipes for canning on my own or am I forever stuck following well tested recipes for canning?

[runwestierun]

Please forgive me for interjecting my two cents but I want to caution you to proceed very carefully. Each food has a different acid content. That's the hard part. And botulism is colorless and odorless and grows in an anaerobic environment.

You say you've recently started canning. I understand that you would want to develop your own recipes. Before you do that, though, you have to very honestly inventory your understanding of every part of the process because the consequences are so great. I feel very strongly about this because my neighbor accidentally killed her husband by tweaking her canned asparagus recipe. And it took him months to die his horrible slow death. Botulism poisoning is so awful.

It's sort of like my neighbor, Lyle. He read a book about mushrooms and went hunting. He found some that looked right and thought they'd probably be OK but they weren't and now he's blind. Please make sure before you strike out on your own that you are not doing something that's "probably OK". As you go through your learning process, be absolutely sure that what you are doing is safe. And good luck!

[Pilori]

Thanks for the heads up runwestierun. That is exactly what I am trying to avoid. I'm just wondering if there is some acid/sugar/salt ratio or pH I should always strive for or am I just stuck tweaking spices on already established recipes.

[djyee100]

The USDA puts out extensive information on home canning, here:

http://www.uga.edu/nchfp/publications/publications_usda.html

I haven't looked at the materials in years, but way back when the manual gave info on testing for proper ph in canned foods. Each food will have different requirements, and possibly even a different processing method (e.g., pressure canning).

I totally agree with Runwestierun. Home canning is a science, and not a place to experiment if you are new to canning. The master canners I know, people who have canned meat, veg & fruits for 20+ years, have extensive experience with established recipes and understand the process very well. Even then, they often use reliable recipes--there are so many canning recipes and canning cookbooks out there that might suit you.

edited to add:

If interested, you could check out the canning classes given by USDA Extension, either online or in-person at various Extension centers throughout the US. The classes are available for free or for a nominal fee. Try Googling "usda extension canning classes."

Edited August 20, 2010 by djyee100 (log)

[jgm]

Your local extension office might also have information that would be helpful to you.

There are so many canning books out there, I think it would pay do an extensive recipe search before you consider any tweaking. You may well run into recipes that are very close to things you'd like to try, anyway.

The cautions in this thread previous to this post are extremely important. Of all the areas of cooking, this one is probably the most dangerous from a food safety standpoint, and the easiest to screw up without knowing it. If you have a piece of roast chicken that is still pink inside, it's obvious it needs to be cooked more. But as runwestierun pointed out, you won't always know when a canned item contains deadly bacteria. Sometimes it will cause gas to release, and maybe even mold formation, but you can't count on those telltale signs.

One of the most important things I've learned from others on eGullet is this: when food goes bad, it's not just bacteria production that's the problem. The bacteria produce toxins. Simply bringing the food to a certain temperature threshold again doesn't take care of the problem; it may kill some, most or all of the bacteria, but it won't remove the toxins they produced while performing their life's work. Always err on the side of safety.

[Wholemeal Crank]

As I found out when I was trying to decide which ingredients to add or leave out of a canned version of a homemade soup recipe, the variables include things that are highly non-intuitive.

To prevent botulism, every bit of the canned product must be acid, or held at a sufficiently high temperature for long enough time to kill the botulism spores. So....when you're looking at a recipe for a vegetable soup, and considering altering it a bit, consider the possible substitution of vegetable X for vegetable Y: do you know if vegetable X will alter the pH balance of the recipe? will it take more or less time to reach that 'safe' internal temperature to kill any bacteria or spores in the middle of a chunk of it than it would a similar piece of vegetable Y (what's it's heat capacity?)? will hard, dense vegetable X it absorb less liquid from the broth and thus maintain a higher internal pH than porus vegetable Y?

There are so many variables: pH, piece size, density, absorption, heat capacity--those are just the ones I can think of off the top of my head. It's just not something to mess with until you've got a very very good idea what you're doing. The once or twice I felt I had extended processing times to sufficiently to truly cover all the possibilities of my changes, AND taken the recommended precaution of making sure that a non-acid canned food is reheated to boiling for the recommended fifteen or twenty minutes after opening (to be really really really sure you break down any botulinum that may have grown because of an error in the original processing) I was left with custom made mush.

I play fast and loose with my jams made from acid fruits, because botulism is out of the picture, and I don't worry too much about my meat and vegetable stocks because they're just flavored water. But I've given up on having stocks of curried lentils and split pea soup and all the other dishes that seemed to natural for home canning. Just not worth the risk for the results.

[Tom Gengo]

I feel very strongly about this because my neighbor accidentally killed her husband by tweaking her canned asparagus recipe. And it took him months to die his horrible slow death. Botulism poisoning is so awful.

It's sort of like my neighbor, Lyle. He read a book about mushrooms and went hunting. He found some that looked right and thought they'd probably be OK but they weren't and now he's blind.

I hope you do not live in Charleston, SC b/c, nothing personal, I DO NOT want to be your neighbor.

[runwestierun]

I hope you do not live in Charleston, SC b/c, nothing personal, I DO NOT want to be your neighbor.

Back at ya, Melon Kittie. Boy howdy do I have a jar of home canned salsa for YOU!

[budrichard]

Boiling water bath canning is for high acid foods ONLY! As previously mentioned botulism cannot be killed by the boiling water bath method. The only method approved for low acid foods is pressure canning where the foods are taken above 240F to kill the botulism spores.

You mentioned that you canned beets in a boiling water bath, was it an approved recipe for high acid? If not, your beets are NOT safe to eat.

USDA, as already mentioned, has a whole section on canning and recipes that should be used and followed to the letter. There are also many State sources. Recipes that you find Posted by non-professionals should be avoided.

I have used the water bath method for many years and have recently purchased an 'All American' Pressure Canner. While expensive, its a well made product from Wisconsin and the weighted pressure control is just about foolproof in maintaining the correct pressure.

I suggest you obtain some definitive works on canning or peruse some Governmental websites and not make up your own recipes. Good luck!

BTW, your recipe looks more like a 'Refrigerator Pickle' than a canned /processed pickle.-Dick

Edited August 22, 2010 by budrichard (log)

[sparrowgrass]

Wholemeal Crank--follow the directions and use a pressure canner for stocks. Gelatin (like the stuff in nice home-made stock) is used as a growth medium for bacteria in labs.

Just sayin'.

[Pilori]

Hm, all good advice.

I guess my next question then how does one take the step toward commercial canning?

[percival]

You want to look into pressure canning, in which case hi/low acidity is a non-issue.

[budrichard]

I suggest this reference guide and this canner both of which I use.

http://www.uga.edu/nchfp/

http://www.allamerican-chefsdesign.com/Product-Detail.asp?hProduct=34

-Dick

[Pilori]

Thanks!

So, if I use a pressure canner can I, in theory, can whatever I like no matter the acid content? If not, how does one develop safe recipes for the commercial environment that are directly copied out of a book?

[percival]

Generally what you can't pressure can is food that can't handle pressure. They're safe to eat, but just undergo volume/texture changes that make pressure canning not possible. Certain things like grains and beans foam up. You'll have to do some research to find out what you can can and cannot can. (LOL)

[budrichard]

In answer to your first question, no.

Recipes for canning whether boiling water bath or pressure canning are developed by Federal or State Agencies with the resources and laboratories to insure safe results. You don't have a lab to test your results for safety.

In answer to your second question,

you would need a certified lab to determine whether or not your recipes and processes are safe.

Remember that every few years that even among commercial canners there are instances where pressure canned items are recalled for safety.

I always use an approved recipe. There is a recipe going around called 'Annie's Salsa' that uses a minimal amount of vinegar and is touted as being safe for pressure canning. I will not use the recipe as I can't find any approved source for this recipe.

Most salsa recipes are only for pints. I use a recipe for quarts and pressure canning from the National Center for Home Preservation called Mexican Tomato Sauce which is actually a nice salsa type with low vinegar.-Dick

Edited August 28, 2010 by budrichard (log)