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Tuesday, February 4, 2014

Beginning Pressure Canning :: Understanding Pressure Canning

Have you been thinking about giving pressure canning a try but just don't know where to start?  If so, this series of posts on Beginning Pressure Canning is just for you!

I have had so many people tell me that they would love to pressure can, but it can seem like an overwhelming thing to begin.  One of the biggest hurdles that kept me from first using my pressure canner, which I hid in a cupboard for three years after acquiring it, was that it was just kind of scary to me. There were a lot of things I just didn’t understand.  Once I got up the nerve to give it a try, it still took me a while to get the hang of.  

Now, however, our pressure canner is rarely hidden in the cupboard.  During the growing season, it is out canning produce from our garden, and during the winter months, it is busy canning seasoned dried beans, meats, broths, etc. 

Understanding Pressure Canning 


This first post on Beginning Pressure Canning is going to look at Understanding Pressure Canning. Hopefully after this post, you will understand a bit more of what it takes to pressure can, what pressure canning is doing, and how to ease concerns about the safety of pressure canning - safety during the process and safety with the food you have preserved.  Please keep in mind that this is just my overview, and it is not meant to replace the information that is included with pressure canners.

What is Pressure Canning Doing?

There are many ways food can be stored long term without spoilage and harmful bacteria growing such as freezing, dehydrating, pickling, and fermenting.

If you want to store a food product in a jar without one of the above methods, you still need to make sure that you have an environment where bacteria won’t grow.   One of the ways to do this is through a hot water bath, or bringing foods to the recommended boiling point before sealing in a sterile container.  This can be done without the use of a pressure canner, but only for those foods that have a high enough acidity. 

Foods that don’t have this high acidity, however, need to be pressure canned. Through the pressurization of a pressure canner, the steam trapped inside the pressure canner reaches a temperature higher than the temperature of boiling water.  With the proper amount of time and pressure used, the temperature of your food will reach a point to kill the bacteria within the food, and the seal of the jar and lid prevents additional bacteria from entering once the canning process is through.

Is Pressure Canning Safe?

There are often two concerns people have that keep them from pressure canning. 
  • Will the food be safe to eat?
  • Will I be safe!?
Yes, there are some horror stories with pressure canners.  Yes, you do need to respect them.  But, just like getting into a vehicle and getting behind the wheel, there are rules set in place to keep you safe.  You just need to know the rules and follow them.

First off, your safety.  Pressure canners can get under a lot of pressure, but they now have many safety features to prevent problems.  One of my fears was that my pressure canner might blow up while in use, until I learned about all of the safety features that are built into pressure canners now.  

Pressure canners now have a pressure spring under the lid (pictured inside the handle on the underside of the lid), which drops into a notch on the canner (pictured inside the handle of the canner). This spring and notch locks the lid so the lid can't be worked off while under pressure. Also, to prevent pressure from building inside of the canner if the lid isn’t positioned properly, the spring will not drop in place and the plug attached to the spring (shown to the left of the lid's handle) will not close.

Another safety feature is the safety valve (shown on in the bottom left hand corner of the picture). If the pressure vent (shown in the center of the canner's lid) should become plugged for some reason, the safety valve will pop open.  If that isn’t enough, many newer canners also have a little window where the gasket can blow out if the pressure becomes too high.  As you can see, pressure canners are much safer now than they used to be generations back.

So how about the food safety? This area requires two things.  First you need to trust that the experts know what they are talking about when they set given times and pressure requirements for safe canning. Second, you need to follow these guidelines and not budge.  If you do these two things, and your jar remains sealed, your food inside is considered safe to eat. If in question, there is a popular saying that those who pressure can use (and really anyone who works with food should use).  "If in doubt, throw it out." 

What do I Need to Pressure Can?

If  you are still reading and still interested in giving this a try, you will need a few things in order to pressure can.

Pressure Canner
Pressure canners come with either dial gauges or weighted gauges.  A dial gauge displays the pressure within the canner on a dial. It is advised to yearly have your dial checked at your local extension office.  I prefer to use weighted gauges, which will jiggle or rock when the proper pressure has been reached inside the canner.  These gauges do not need to be tested.  For the purposes of the rest of my posts, I will be talking about canners with weighted gauges.

Pressure canners can be purchased new or used.  At one point in time, I had 3 used canners.  (This was before one was warped the time it steamed all of the water out after I had ran outside for what I thought was a quick chore of getting a stray animal off of our farm.  It wasn’t a quick chore, which reminded me to stay inside while canning or just turn the canner off.) One of these three canners was purchased at a garage sale, and two were given to me by individuals who no longer used theirs.   All of that to say, new canners are great, but used canners are fine if you know what to look for.

(If you notice, one of my canners is taller than the other.  They both can the same amount of jars, but the taller canner works much bettter when I just want to do a hot water bath to preserve my food. Even though it is heavier and hard to store, if I had to choose one or the other, I would definitely choose the bigger one for this reason.)

If you acquire a used canner, you will want to make sure of a few things.  First, you will want to look over the safety features.  Check out the lid, and make sure that the safety spring is in place and moves, the vent is open and not plugged, and that the overpressure plug is solidly in place.

Next you will want to look for any warping of the pan, just in case someone accidentally steamed all of the water out and warped it or something . . . as if someone would do such a thing.  To do this, find a ruler or another flat item to lay across the bottom of the pan.  By doing this, you will be able to tell if the bottom of the pan is still flat. You will then want to look inside to make sure the integrity of the pan is still good.  The metal should be smooth and free of any pitting or gouges.

If you have determined the pan looks safe, you will then want to check to make sure the canner can be functional.  It should include a round jar rack to be used on the bottom of the canner which keeps the jars from sitting on the direct heat, a weighted gauge that is marked for 5, 10, and 15 pounds of pressure or the newer separate gauges or rings which create 5, 10, or 15 lbs of pressure, along with a rubber gasket to seal the canner.  You will also want to make sure that this rubber gasket is not dry and cracked or else it will not make a proper seal. 

I realize that this is a lot to consider, but remember, I had never canned before, and all 3 of my canners came to me used. If you know a friend who pressure cans, you can have them look them over for you too for piece of mind.

Heat Source
You will also need a heat source for your canner. The most common source of heat is a stove. There are other options, but for beginners, a stove is the way to go.

The best and easiest stove to can on is a gas stove, which allows for instant adjustments to your heat.  It usually has more level of a burner to set your canner on too, which does have implications on the pressure inside your canner.

With this said, I have only had stoves with electric coils.  These are a bit more challenging to can on because the coils do not cool off and heat up immediately when you are wanting to adjust temperatures, and they also usually have pretty unlevel burners.  With a bit of patience and learning, however, these stoves can be just as efficient to can on.

The third type of stove, which presents a few more problems, is a flat top stove.  Many people will say that you cannot pressure can on a flat top stove, but I have also heard of individuals who personally contacted the stove company and received information on how to use a pressure canner on their stoves without causing the stove damage. 

Canning Jars and Tools
After you get your canner and heat source figured out, it is time to start collecting your tools.

Jars, lids, and rings are the number one item that you will need.  Keep in mind that although you can use any jar laying around for hot water baths, you will need to have mason canning jars for pressure canning, which are made to withstand the pressure of the canner.  You will also need to use a new lid each time you can, which is fun to make little notes on, to ensure a proper seal. You may reuse the rings that hold the lid in place until the seal is set.

There are many tools that can be purchased for pressure canning, but I would recommend at least having a jar funnel and jar lifter.  Unless you are much more coordinated that I am, you will greatly appreciate a jar funnel and the ease and containment of messes it provides when filling jars.  And although I usually add the safety of a potholder underneath hot jars when I move them, a jar liter is able to give you a tight grasp on hot jars which contain scalding liquids.  Also handy is a lid lifter to retrieve lids out of the hot water that softens the lids' seals before use.  And although any spatula can be used to remove air bubbles, there are also spatulas designed for this purpose which include markings to make sure you have the proper headspace, or correct fill, for your jar.

Canning Instructions and Recipes
If you have purchased a new canner or received the instructions with a used canner, you will want to carefully look these over.  The instructions included should tell you the times and pressures needed to safely can each of the foods that you would like to preserve, along with how the canner's specific weighted gauges should work.  They will also explain to you how to adjust for various altitudes which might impact the pressure inside your canner. Since there are so many combinations of times and pressures, depending on what you are canning, you will want to have these instructions handy each time you can.  If you happened to get a used canner without instructions, you can usually download or request instructions from your canner’s company.

I spent a couple years canning with just the instructions that came with my canner, until I finally purchased the Ball Blue Book Guide to Preserving.  I wish I would have had one of these books when I first started.  Not only did this book explain the process and science of canning more thoroughly, helping me to be more confident when canning, but it also has some wonderful photo tutorials and instructions for canning more foods than I could ever dream of canning.  If that isn’t enough, it even has information on proper freezing and dehydrating to preserve foods.

Now What Do I Do?

If you are feeling a little more comfortable with the idea of canning, here are some next steps you can take.
  1. Find a copy or purchase the Ball Blue Book Guide to Preserving and read a bit more about the principles of home canning.  If you know individuals who pressure can, it might not be too hard to borrow a copy.  If you end up not deciding to pressure can, this book has great information that you can apply to freezing foods or preserving with just a hot water bath.
  2. Begin collecting the things that you will need to pressure can.  If you don’t have money in your budget to purchase everything new, don’t be afraid to search for used items through want ads and Craig’s list or even just start asking around.  You might be surprised at the responses you get through a quick post on Facebook, especially with jars that people have been storing and are happy to pass on. 
  3. Look forward to Part 2, where I will share about The Pressure Canning Process!

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Tools of My Trade



THANK YOU!! THIS IS just the post I needed to read. I have been scared of pressure canning even though we have hot water bath canned for a few years. I am now ready to find a pressure canner & am confident I am equipped with the appropriate information. THANK YOU!

The Beginning Farmer's Wife said...

You are welcome! I've had so many requests to hold classes on different homesteading skills, but due to many limiting factors, this is the best I can do. I'm so glad it is helpful for you - hearing feedback helps make it worth my time. :)

Laurel Nguyen said...

What a fantastic post! Thank you for sharing your experience!

Anonymous said...

Love the post! Never canned before but want to can my veggies from my summer garden this year.. excited to try it!

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