Home Canning: What is it and how do I know it is safe?

I was recently cruising around the interwebs looking for some interesting canning recipes I can bastardize.. err… CUSTOMIZE around food allergies and available goods. What I found were pages and pages and pages of terrible (even potentially deadly) canning advice and storage.

Between the reaction I got on Facebook, my blog and my coworkers it became evident that not only do many people who do home canning not know what the hell they are doing, they are giving their potentially deadly goods AWAY. No. Just NO. If you wanna play games with your own health and safety, go ahead. Don’t give your goods away to unsuspecting people without giving them full disclosure.

I am going to address home canning in general and then give very specific questions to ask before you accept home canned gifts.

First things first, how does canning work?

Home canning and commercial canning are actually the same process, just vary in scale and temperature. The act of home canning is NOT to create a vacuum (seal) on the jar. During canning, the contents are heated to kill the enzymes and bacteria in the food. During this process, all oxygen is forced out of the container creating an anaerobic environment that MOST pathogens cannot survive in. No air, no pathogen… except for Botulism and a few other nasties.

It’s a two part process; heat to kill bad things while vacuuming out all air. Seal said container to keep it that way. Glass, plastic, aluminum, steel.. the process is pretty much the same. There are, however, variables.

Variable 1: Is it home canning or commercial canning?

Home canning is very limited in the temperatures attainable. Partially because of containment vessels, partially because of temperatures home appliances can reach, partially because of the need to safely handle food without burning yourself. On the plus side, YOU control what goes into it. No crazy chemicals, no parts from 500 chickens, no worries about cross contamination unless you do it YOURSELF.

Commercial canning has the ability to heat things to much higher temperatures and more stages of canning. Few hands touch things since machines do much or all of the work, so the foods are at much higher temperatures for a while before they even SEE the containment vessel.

If you are home canning peach slices, you are handling warm (at best) peaches. Commercially canned peaches are at about 100 degrees when they are sliced. The enzymes are dead, they have been through a scalding hot bath in a tank of hot preservative and chemical laden water. See the difference?

Variable 2: Is it a low acid or high acid food?

This is *HUGE* the presence of acid means that you can process at lower temperatures and pressure and have a safe product. The acid does a fair job of killing many of the nasties on its own. Apply heat and you are set.

Foods that are high acid, like fruit, tomatoes, jams, etc. can be processed in what by the waterbath or boilingbath technique. This is where you put the food in the container, put a sterilized lid and band on it and completely submerge it in water. You then boil the water and when it reaches a full rolling boil you start a timer for the amount of time needed to process (usually found in the recipe, but there are charts available). When the time is up, you remove the jars from the boiling water and place them lid up on a towel on a counter and allow them to fully cool. You then remove the bands, test the seals, and label. Anything that didn’t seal can be reprocessed right then and there.

Foods low in acid need a completely different processing technique. You have to use a pressure canner. NOT A PRESSURE COOKER; a Pressure CANNER. They have a rack or a metal plate across the bottom to allow water to circulate beneath the jars and use a tiny fraction of the water that a boiling bath canner takes. There is a fill line on the inside that shows you how much water to add. Fill it with water FIRST, and then add your jars of low acid food. The recipe or chart will tell you how much pressure you should apply to each jar type for the low acid food you are canning.

Off the top of my head (and if I were actually doing this, you better believe I would confirm) you would put the jars into the pressure canner, close, lock the lid and then start the burner. The canner must “vent” for a while. This means that 20 or so minutes after you turn the burner on, steam will start coming out of the open vent. Once it is vented, you apply the weights (the food being processed determines the weight) and the lock should pop up making sure you can’t open it while under pressure and burn the hell out of yourself like my mother did. She still has scars and it’s been 35 years.

When the weights start “rocking” or shaking, you start the timer and get used to the infernal racket for the next 90 minutes. At the end of the 90 minutes, you turn the burner off and let the canner cool.

After about 45 minutes, or when the lock releases, you can remove the weights. Give it a few minutes to vent again. Then remove the lid. POINT IT AWAY FROM YOU. I steam burned the inside of my wrists a few years ago being distracted and opening it towards me. I dropped the lid on the floor and broke the handles off. Expensive and painful mistake.

You remove the jars and put them on a towel on a counter or table. The reason for this is that a hot jar on a cold surface can shatter. Let it sit there, out of drafts, until it is room temperature. Then remove the bands, check the seals, label and store without the labels. Anything that didn’t seal right has to be reprocessed within 24 hours.

Pressure canning takes a MUCH longer time, but it is the only safe way to can vegetables, meats, mushrooms, greens, anything low in acid.

**If you accept ANY home canned product, ask how it was processed**

Was it waterbath or pressure canned?

  • If it isn’t a fruit, jam, jelly, tomato or pickled product and they say waterbath…
  • Is there wax on the top of the product (it’s an old and bad canning technique)…
  • They say they used aspirin in it…
  • They say they put hot food in it, put the lid on and flipped it upside down with a towel over it?
  • Does it look cloudy, is the lid bulging? Does it smell bad upon opening?

If any of the above statements are true, smile, nod, be gracious and throw it in the trash as soon as they aren’t looking.

  • Is the band on it? (I transport with the band and always instruct people to remove them, so the presence of a band in transport isn’t bad.)
  • If it has the band on it, ask if they store it with the band. If they do, smile, nod, be gracious and throw it in the trash as soon as they aren’t looking
  • Does it have a label with the contents, ingredients and date clearly visible? If not, ask when it was made and exactly what is in it. If they can’t answer, or you don’t like the answer, you know what to do.

However, if they:

  • Do not store jars with the band on it.
  • If they pressure canned low acid foods.
  • Waterbathed high acid foods.
  • Label, and date.

Smile, nod, be gracious and enjoy! (For the record, it is pretty hard to make anyone sick with jams, jellies, and pickled products.)

If someone tells you that “I do it just like my grandma-aunt-cousin-uncle-grandpa-mom-dad and no one ever got sick!” Smile and nod but don’t eat it.

Two true tails of bad canning:

My mother canned. A lot. She got severe third degree burns from a pressure cooker exploding on her when I was a toddler that left her with horrific scars on her stomach and leg. After that, she wouldn’t go near a pressure anything.

She also didn’t can again until I was a teenager. She decided to can some green beans, new potatoes and ham. She processed them in a waterbath canner for an hour. We ate some about a week later and everything was fine. We ate some about a week and a half later when my middle brother and his family were over for dinner. He liked it so much he said he might have her make some for hunting season.

Then we didn’t eat any for about a month. I came home late from work, picked up a can and saw that it was cloudy, but home canned goods can sometimes get that way. I took the band off, popped the lid (and heard a hissing that I didn’t understand) put it in a bowl, microwaved it and spent the better part of the next week trying really hard to not die. I will spare you the horrific details, but I had food poisoning.

Pretty much everything she did to process was done wrong. She washed the jars, but didn’t boil them, she waterbathed extremely low acid foods, and left the bands on. I’m lucky I didn’t die. I took a class in safe canning practices after that and found out that my well-meaning mother had been using dangerously outdated canning techniques that she had gotten from her mother. Like putting a layer of wax over your jam to seal it. Actually, jam is just super hardy between the acid of the fruit and the sugar, it’s pretty hard to weaponize.

My mother was very gracious and was more than willing to change her canning methods, but drew the line at going near a pressure canner. She just stuck to high acid foods and froze everything else.

Recently, my MIL came for an extended visit. She brought with her a bunch of home canned goods as gifts. Right off the bat I thought something was up. I started taking bands off to put them in the pantry and she asked me what I was doing. O.o

I explained and she said “well I never knew that! I always leave the bands on!” ummmm “how long ago did you make these?” She said a few months before. I smiled, nodded, put them in a little cluster in the pantry and told the kids not to eat them unless I checked them first.

A week or so later when I was canning something, she told me that she doesn’t bother with waterbaths, she just puts the hot food in a jar, puts the lid on and flips them upside down on the counter with a towel over them to seal them. I’m pretty sure the look of utter HORROR on my face gave something away.

I really like my MIL and did not want to hurt her feelings but I really HAD to tell her how dangerous that was. She has had several serious stomach flus and illnesses since she moved back to Michigan and I just then got an idea why. I pulled out several modern canning books; one has a section on dangerous old habits, and right then and there gave her one of my Ball canning books. I even went so far as to pull up the USDA safe canning instructions and acidity charts.

Fortunately my MIL is also very gracious and more than willing to adopt safe practices. The validation occurred a few weeks after that when we kept hearing a “pa-PING” in the pantry. We finally tracked it down…. to her canned goods. It was the seal on one off her jars trying to break and it couldn’t because the band was on it.

Whew! That was a close one and she got to see with her own eyes the consequences of unsafe canning methods.

If you are a canner, please look up the most current safe practices. This is your tax money at work, please take advantage of it!! The USDA has many publications, and you can check them out online.


Many county extensions and community colleges offer canning classes if you need a refresher.

Canning is great if you do it right and follow the rules! I strongly encourage people to get involved with canning and making your own food. Just be safe with it!

wpid-20130806_221957.jpg (fresh out of the canner, bands still on because they are hot)


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