By Andrew Skousen – Originally at World Affairs Brief and reprinted here by permission.

Most canning sites err on the side of caution and recommend long processing times and, preferably, a steam canner. As I noted in the last preparedness tip, I prefer steam bath canning for faster processing with less energy, but you have to know its limits and the bacteria you are fighting. For home canning the main fear is botulism and here’s why:

Cl. botulinum is a bacterium that is all around us in soils and the environment. It survives difficult conditions by forming spores that are resistant to heat, chemicals and drying. Under favorable conditions the spores develop into bacteria (germination) and the bacteria grow in the food. During growth they produce a potent neurotoxin (nerve toxin called botulinum toxin) that causes the illness [botulism].

The botulinum bacteria itself is not the problem—our own gut can handle them in small amounts—it is their neurotoxic byproduct, especially when it accumulates in food under the right conditions: no air, room temperatures, neutral pH, low salt, and low sugar. Unfortunately, some bottled preserves (principally meat and vegetables) sitting on the shelf have these exact conditions. Botulism symptoms include blurred or double vision and gradual muscle paralysis. In extreme cases it can paralyze the lung muscles and cause death (artificial respirators are used now to save most patients). Recovery can take months while the body regrows the damaged nerve endings.

Some sites report that botulinum bacteria may not always cause a bad smell or taste. But don’t fear this invisible threat yet. To ensure botulinum spores are killed all portions of the food must be heated to 250 deg F (121 deg C) for 3 minutes. These temperatures can only be reached with a pressure canner. So why didn’t our great-grandparents get sick more often using water bath and steam canning? They found other ways of inhibiting the spores: Acidic environments (pH less than 4.6), high sugar (>50%) and/or high salt (>7%) inhibits the spores from developing. That is a lot of sugar or salt, so acid is really your best bet.

Many of our great grandmothers canned meat and veggies without a pressure canner, but I suspect they usually cooked these when adding to a meal. The botulism bacteria and its neurotoxin are both neutralized by heat—even just simmering the jar’s contents at 176 deg F (80 deg C) for a few minutes does the job. Don’t throw out suspicious food in hard times, just cook it well. Unfortunately the fear of putting a recipe or instruction out there that might allow for botulism has caused many to throw out their old family recipes and processing instructions so we are mostly stuck with pressure canner instructions for these products.

Fruit and most tomatoes are acidic enough for atmospheric steam canning (despite what you hear), but some hybrid tomatoes are bred to be so sweet they need two tablespoons of lemon juice per quart jar to get the pH level low enough. Many people also add lemon juice to applesauce for the same reason.

A hand-crank applesauce/tomato sauce mill is very useful in home canning. We also pull out the steam juicer for grape and berry juices. Other tools are also extremely valuable depending on your produce: a cherry pitter, pear corer, jar lifter to avoid scalding when removing hot jars and a large-mouth funnel (that fits small and large mouth jars) as seen on Victorio’s website. They are available at kitchen supply stores (and hardware stores seasonally). Next week I’ll cover the options for canning lids including some that are reusable


  1. Good time to have articles on this topic. I would also like to see some main meal canning ideas. I can about everything, but I can ingredients; not a complete meal. Anyone with ideas please send to MD for posting.

  2. mom of three says:

    The only problem with the article, I would never eat anything that might have a problem with it. I have dumped peaches, that grew to dark for me to eat I always smell and look at anything I’ve canned. I also never eat canned food that other people canned, I have no idea if their cleaning is like my cleaning, or canning methods are like mine. (Unless in know them very personal) . I can’t wait for the second article, I’ve been very curious at the reuseable canning lids.

    • Santa Walt says:

      If you discard food canned by other people because they might not meet your standard of cleanliness, you are wasting food, if it is pressure canned. Pressure canning kills the bad germs both inside and outside the jars. As long as it sealed, even if it doesn’t look very good, it is probably good. Now if it smells bad, that’s a different story. The jar was likely not sealed good or its very old. Don’t let you imagination of germs cause you to waste good food.

  3. DW’s new stove top canner does water bath of steam. But right now she is just starting out. Making excellent jam. We like low sugar/honey and can only get Strawberry at the store.

    It reminds me of when I got started reloading. If you wanted something special you had to make it at home.

  4. great info, tyvm….have recently added canning to my skillset….. some jams, pickled (home grown of course) beans, today 16 pints of meat loaf (broke in new pressure canner!)- prefer rough chopped onions & emiril’s portions of garlic, but figured it’s best to follow recipe….

  5. 2moro chili! Growing ghost chili peppers in garden….. if u see mushroom cloud up Chicago way, check it out b4 bugging out…..

  6. Canning food is/can be expensive, time consuming, fun, healthy and is/can be inexpensive. There are reasons (sound science based reasons) for the recommendations on what can safely be canned and the time frames used. I have to second mom of three – if I’m not sure that the product has been canned in accordance with safe canning recommendations I won’t eat their canned product.

    Tastes have changed and what the public will accept in their fruits and vegetables have changed. Acid levels in tomatoes and some apples have been lowered because the public wanted less acid in those products. For safe home canned product acid has to be added back in.

    Botulism is a very real illness that can kill. If it doesn’t kill you it can leave you with long term (sometimes permanent problems). I have listened to an interview with a woman who contracted botulism in the 1960’s or 70’s from a baked potato that wasn’t kept hot but was tightly wrapped in aluminum foil (creating the anaerobic environment botulism likes). She lived but what she went thru was horrible.

    Please don’t take chances with low acid foods – can them in a pressure canner for the recommended level of time with the proper weight.

  7. TimeHasCome says:

    I love my pressure canners , I own seven of them . That would include the All American Cadillac models . But my favorite canner is a 60 year old Sears and Roebuck 7 quart canner . Probably because it heats up so fast and requires so little energy to keep it at 15# pressure . I cook everything at #15 pressure mainly because I am at 1,000 elevation and it’s only a few degrees hotter than 10# pressure . In pinch they make a great autoclave to sterilize anything . I have used and abused these canners for years and I a sooo glad Americans are terrified of them .

    • TimeHasCome says:

      In my garage I have what I call my ” StandSteer” . That is a floor to ceiling shelf with 400 pounds of meat on it . It would consist at about 200 pounds chicken and 150 pounds beef and 50 pounds pork and bacon . These are all in large mouth quarts only . Which is about 2 pounds of meat per jar . Two of use can can about 120 pounds in a eight hour day using 5 to 6 canners . Polka Casaba canned is OK but hotdogs canned go for dog treats .

  8. ….for those keeping thread going…. the chili experiment went off w/o mishap Sunday….! I used reg mouth jars (vs wide mouth for meatloaf 2 days prior), this time my stove’s heat setting was lower to maintain pressure than prior setting. As I packed more reg sized mouth jars in this time, I feel this was reason. Anybody know about how long these will last in low light, cool, dry storage area? TYVM. Lastly, followed a # of you tube tutorials for all canning endeavors thus far, plus did some reading in fda manual & Bett Hms& Grdn book…. attended 1 class last yr, too. Not an expert, but did my research!

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