How does pressure canning work

[Tx_Woman]

Ok, so I have a friend who told me she does canning. She uses the "simple" canning method. She boils all the jars, lids etc. and brings her food to a boil, puts it into the jars, turns them upside down, and in 20 min. you'll hear a pop, and they are done. She has done this for a long time and has never had an issue. She mostly does salsa this way and it's lasted for months with this method.

 

I was discussing with my mom and it made us wonder what exactly the pressure cooking does to the inside of the jars to make them any different than what she does? I loaned her my books so don't have them in front of me. Was hoping someone could explain that easily?

[WormGuy]

In a nutshell, pressure canning raises the temperature of the food to a point where it kills bacteria that can kill you if you do it any other way. This applies to low acid foods such as meat, green beans, soups, etc. I hate to tell you that what she does is not safe at all. Hopefully Violet can comment in a better way.

 

 

 

John

[Cat]

Dittos to WormGuy's comments... she may have had no problems in *forever*, but it's an old and dangerous way to "can".

 

The simple explanation? This is what I wrote in my "Canning 101 thread":

Canning foods interrupts the normal spoiling process of foods. Using the two-piece vacuum sealing caps, heat destroys microorganisms and at the same time drives out air. When the jar cools, the lid seals onto the jar and prevents microorganisms from entering and contaminating the food. A perfect seal is required for this, so never reuse lids, only the screw bands which hold the lids until sealing.

 

http://mrssurvival.com/forums/index.php?showtopic=14590

 

She may be boiling everything, but her method leaves air in the jars that is not heated sufficiently nor is driven out. That air *could* contain something dangerous that can grow and spoil the foods. She is probably ok only because most salsa is so acidic that it *might* help kill bad stuff, but I sure wouldn't be willing to risk my family's health on "maybes".

 

Some people "can" in their ovens. Some use old steamer equipment. But they are just not safe. They don't use enough heat or pressure.

 

You're a good friend to try to show her a better, safer way. Even if she doesn't listen, you've tried.

 

Please, if you're going to put your money, time, and efforts into home canning, do it right. We don't wanna lose you!!!

 

 

 

[Violet]

It is VERY dangerous what she is doing. Especially with salsa, since I am also guessing she is making up her own recipe or using some recipe that was never meant to be canned.

She is at a risk for botulism. You cannot see, taste, or smell botulism. The amount on a head of a pin can kill over 63,000 people. No, that is not a typo.

Just because she has beat the odds so far doesn't mean she always will.

What she is doing is totally nothing to preserve foods. No bacteria killed. It is all sealed in the jar, just waiting to grow. I am surprised she is surviving so far. Plus, she doesn't even have a true vacuum seal. That is only a weaker surface seal. You process to destroy bacteria, molds, and yeasts, plus to get a true vacuum seal.

Oven canning is just as bad. So is a steam canner. Not a steam PRESSURE canner, but a steam canner. You use a pressure canner, not a pressure COOKER to can in. They are not the same. A cooker is a small pan and only safe to cook in. Unless a canner can hold at least 4 quart sized jars it cannot be safely used to can in. You can only reach 240 degrees in a pressure canner. That is what it takes for low acid foods to kill botulism. You can boil water the rest of your life and never get it hot enough to kill botulism in low acid foods. High acid things like fruits, jams, and properly acidified pickled foods can be done in a boiling water bath canner. I would also guess she is not adding the required bottled lemon juice or citric acid crystals to plain tomatoes. Canning is an exact science.

Plus, only safe, tested recipes should be used. Not just any book or person online that provides information means it is safe. Unless a recipe is tested in a lab for ph and density it will not be safe to follow. Please, use current Ball Blue books or any of the USDA tested recipes for canning. Do not make up your own recipes or add ingredients not called for. They need to be followed exactly. Even down to the right headspace.

You can find the safe info free here. There is also a free online course you can take :

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

 

In a nutshell, proper preserving destroys bacterias, mold, and yeasts. It causes the air to be expelled from the jars and that is how a vacuum seal is made.

(I teach food preservation and food safety at my local county extension office. I am an employee there.)

[HSmom]

A sealed jar doesn't guarantee a safe jar.

[Tx_Woman]

ok, thank you all! I do not plan on doing anything outside of what is considered up to date and safe, nor will use untested recipes. I am a good direction follower so i'm good with that. I will be directing her to these sites as well because I fear she doesn't understand this. Plus hopefully, she was able to read thru the Ball Bluebook I loaned her.

 

Thanks again!

[Violet]

You can have her email me. I will put the fear into her, LOL !

I do hope she will change her dangerous ways of doing things. Please, let me know if I can help. I promise to be nice.