Canning 101: Pressure Canning

Pressure canning is an excellent way to open up your pantry to all sorts of preserved meats and vegetables. Rather than limiting your shelves to jam, why not try green beans? Or stew meat? Or even soup? Because of the process, pressure canning is able to preserve food while preventing the problems associated with low acid canning which puts your preserves at risk for botulism.

But why does this matter? Well, botulism doesn’t die before 240 degrees. If we force water to boil at 250 degrees, the water content of our canning ingredients will boil at a higher temperature as well. This means the temperature will be high enough to kill botulism toxin. And that’s important for safety’s sake.

Before we move on, here’s a little science lesson about pressure canning. Here on Earth, we have an atmospheric pressure of 14.7 pounds per square inch (psi) at sea level. Because a pressure canner increases the atmospheric pressure of the contents within it (zero on the canner equals our regular psi), it can force water to boil at a higher temperature than in our typical atmosphere. In fact, instead of water boiling at 212 degrees, a canner can force it to boil at 250 degrees. So when we talk about pressure, we’re referring to atmospheric pressure.

*If you haven’t read the blog about canning safety and botulism toxin, I highly recommend you do before you begin. It is important to understand safety concerns when preserving food and this is a good explanation why.* The first thing you learn in that article is to follow the rules. Use fresh, clean produce. Use clean, intact jars and lids. Follow the recipe – making sure it’s an approved one. And process the jars for the recommended time and temperature or pressure.

Equipment

Pressure canners can be expensive. But they are wonderfully versatile and essential to canning meats, seafood, and vegetables. I encourage you to buy a pressure canner that can hold seven quart jars. It seems to me when I reach for a jar of stew meat, I want larger amounts to use at a time. Pints and half-pints just aren’t enough for a meal. But regardless of the size, the most important thing is to buy a quality canner.

Presto, Aluminum Pressure Canner, 23 qt

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Pressure canners have several unique features. The first is the locking lid and seal. This is important because, as I mentioned above, we will be increasing the psi inside the pot. It would be impossible to do this without an airtight seal. This lid will lock in place and stay locked until psi has returned to normal. This is a safety mechanism. Before you begin pressure canning, make sure your seal is intact. If not, replace it.

Presto Pressure Cooker Sealing Ring

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Pressure canners also have a pressure dial. The dial has a pointer which moves to indicate the pressure within the canner. When a recipe calls for a certain pounds of pressure, this is where you determine it. The standard recipes vary from 5 psi to 15 psi. It is important to have your pressure dial checked for accuracy each year. A gauge that reads high can cause under-processing and may result in unsafe food. You can check with your county extension office to have it tested. If you need to replace it, make sure to choose a dial that works with your pressure canner.

Presto Canner Steam Gauge, New Models

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The little metal “hat” on top of the lid is the pressure regulator. It allows pressure to escape from the canner if it gets over 15 psi – the most pressure a canner can safely handle. It will rock back and forth, hissing sometimes to release excess pressure.

A pressure canner usually comes with its own rack. The rack sits in the bottom of the pot and the jars sit on it. If you purchase a canner without a rack – or your rack gets lost or rusty – you can always replace it without replacing the whole set up. Some racks sit in the bottom of the pot, while others have handles so you can fill the rack with jars and then lower them all into the water at once. I find it difficult to lower them without having jars tip together, so I place my jars on the rack when it is in place at the bottom of the pot. Water is used in a pressure canner, but only a few inches. Instead of boiling, this is used to create steam which in turn increases pressure.

Norpro Canning Rack, 7 Jar

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In addition to the pressure canner, we need jars and tools. You can buy a set of tools that usually includes a jar lifter, a headspace/bubble stick, a funnel, and a magnetic stick. If you have tools for your hot water bath set up, you can use them for pressure canning. They are the same.

Most jars come with lids and rings. When you reuse your jars the next time, you can reuse the rings, but you’ll need new lids (to make sure you get a good seal). You can buy boxes of these separate from the jars. Quart jars come in “regular” and “wide mouth” openings. Your choice. I prefer the wide-mouth because the straight sides are easier to clean. They are all the same volume and that’s what matters.

Ball, 1 Qt Regular Canning Jars with Lids and Rings, 12 pk

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Ball, 1 Qt Wide-Mouth Canning Jars with Rings and Lids, 12 pk

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We’re going to go step-by-step through the process of hot pack canning green beans using the following recipe. You can use wax beans instead. But remember this is only for beans. Each veggie has a different recipe. Hot Pack refers to the liquid used for the jars. Some recipes are Raw Pack which means the contents are not hot when they go into the pressure canner.

Set Up Equipment

Before we start preparing the beans, we need to set up the equipment. Put the pressure canner on the stove, making sure it is level. Put the rack and hot water into the canner. If the recipe doesn’t say how much water to use, best practice is 2-3 inches. It’s ok if the bottom of your jars are sitting in water.

Wash and rinse jars and lids carefully. If they are used jars, check to make sure there are no nicks or chips in the rim. This could keep the lid from sealing properly. Since you aren’t boiling jars, their temperature doesn’t matter. The pressure canner will bring the temperature up slowly enough to protect the jars from cracking.

Green Beans

• 14 pounds of beans
• 7 tsp canning salt (Mrs. Wages Pickling & Canning Salt)
• Enough water to cover beans

Yield: About 7 quarts

Preparing the Beans

Sort and wash tender, but crisp pods. Remove and discard diseased or rusty pods. Trim ends. Leave whole or cut or snap into 1-inch pieces.

Hot Pack

1. Place prepared beans in a large pot. Fill with boiling water until the beans are covered. This gives the heating process a head start so we don’t cook the beans too much.
2. Boil for five minutes.
3. Using a slotted spoon, fill jars loosely with beans, leaving one inch of headspace. That means there are no beans within one inch of the lip of the jar.
4. Add one teaspoon of canning salt per quart to the jar. Don’t worry about mixing it.
5. Cover beans with hot cooking liquid, leaving one inch of headspace.
6. Before you check headspace, you need to make sure there are no bubbles in the beans. To do this, slide the plastic stick down the inside of the jar and run it around the sides. This should dislodge any bubbles that might make it hard for the lid to seal.
7. Now you can check the headspace. Using the same plastic stick, flip the stick around and use the notches. Each notch corresponds to a measurement, marked on the plastic. Setting the one inch notch on the rim of the jar, check to see if it reaches the liquid. Adjust the amount of water until there is about an inch between the beans/water and the lip of the jar. The reason for this is to allow for expansion within the jar while cooking. If you don’t leave enough headspace, you risk the contents leaking while cooking and disrupting the seal.
8. Wipe the rim of the jar with a wet paper towel.. Make sure there are no bits of food left as the lid won’t seal properly.
9. Center a lid on the jar. Take a ring and screw it on finger tight – until you feel resistance. This is meant to keep the lid in place but doesn’t need to be overly tight as the lid will create a suction as it processes.

Processing the Jars

As you complete each jar, use a jar lifter (the weird clamp-type thing), place them into the pressure canner. Make sure to always keep the jar upright. Tilting the jar can cause food to spill into the sealing area of the lid. Repeat this until all jars are full.
When all of the jars are placed in the canner, place the lid on (it will only fit when sitting in the notches) and turn it until it locks in place. Sometimes it’s hard to get the lid in place but keep shifting it gently until it settles onto the pot. Remember, we have a seal to keep intact so don’t force it.

Now that the pressure canner is locked, you can turn on the heat. Remove the pressure regulator and watch until you see a steady funnel of air coming out of the top of the open valve stem. This is called “venting” and it is essential for creating the proper pressure within the canner. Once you see the funnel of air, start the timer for ten minutes. When ten minutes have passed, replace the pressure regulator, and allow pressure to build within the canner. If you don’t do this, you risk having air trapped that is colder than the pressurized steam which can lead to under processed and potentially unsafe food.

Unlike hot water bath canning, you aren’t watching for the water to boil. You are watching the pressure gauge. The amount of time for processing depends on the size of the jar, the contents, and the altitude (remember, altitude affects boiling). There is a chart below that explains the processing times. Follow the timing and psi that best fits your situation. For example, if you live at 4200 ft, you need to process quart jars at 13 lbs of pressure for 25 minutes.

You’ll notice it also mentions the “Style of Pack.” This refers to a hot or cold pack. Like the names suggest, there are some things you fill jars with while they’re cold and some, like this recipe, you fill jars with liquid while it’s hot.
Watch the dial and adjust the temperature on the stove until it is holding at a steady pressure. As the pressure increases, a locking pin will click into place on the handle, making it impossible to open the lid. This is a safety mechanism and lets you know that pressure is building within the canner. If, for some reason, your processing time is interrupted, you have two choices. The first is to restart the timer and process the entire length. The second is to put the jar in the fridge and use it within the next week.

Removing, Cooling, & Storing Jars

When the timer goes off, turn off the stove. The pressure regulator should slowly stop hissing and moving. The pressure gauge will show a decrease. This process can take some time – anywhere from 20-40 minutes. You will know the canner is safe to open when the locking pin disengages at the handle. Carefully open the canner. Remember, steam can burn just as easily as hot water. Allow the jars to sit in the canner for ten minutes before removing.

Put a towel out on the counter. Using the jar lifter, lift each jar carefully out of the canner and onto the towel. Do not tip the jar. As the jars cool, you’ll hear this quiet “pop.” That’s the final sound of the vacuum sealing the lid. Let the jars cool for 24 hours. When they are cool, press down in the center of each lid. If the lid moves up and down, the jar isn’t sealed and should be refrigerated and used within the next week. If it doesn’t move, it is sealed.

Remove the rings from the jars and wipe down any residue on the jar. Label each jar with the kind of beans and the date of processing – either a sticker or on the lid. Find a cool, dark, dry place to store the jars. Rule of thumb is you can keep canned goods for about a year. After that, while it’s still safe to eat, the contents will have degraded and may not be as tasty.

Ball Canning Jar Labels, Dissolvable, 60 pk.

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In addition to preserving basic vegetables, pressure canning gives you the opportunity to explore all sorts of homemade foods. Buy a copy of the Ball Blue Book or explore the recipes on the National Center for Home Food Preservation and you’ll be amazed at all of the recipes out there. And many of your favorite recipes can be preserved by following the rules for the individual ingredients.

Just make sure to follow the rules. Use fresh, clean produce. Use clean, intact jars and lids. Follow the recipe. Process the jars for the recommended time and temperature or pressure.

I’ve included one of my favorite recipes below.

Chili Con Carne

from the National Center for Home Food Preservation

Ingredients

• 3 cups dried pinto or red kidney beans
• 5-1/2 cups water
• 5 tsp salt (separated)
• 3 lbs ground beef
• 1-1/2 cups chopped onion
• 1 cup chopped peppers of your choice (optional)
• 1 tsp black pepper
• 3 to 6 tbsp chili powder
• 2 qts crushed or whole tomatoes

Yield: 9 pints

Prepare Beans

Wash beans thoroughly and place them in a 2 qt saucepan. Add cold water until it is 2 to 3 inches above the beans. Soak for 12 to 18 hours. Drain and discard the water.

Making the Chili

1. Combine beans with 5 1⁄2 cups of fresh water and two teaspoons of salt. Bring to a boil. Reduce heat and simmer for 30 minutes. Drain and discard water.
2. Brown ground beef, chopped onions, and peppers in a skillet. Drain off the fat.
3. Add remaining three teaspoons of salt, pepper, chili powder, tomatoes and beans. Simmer for five minutes.
4. DO NOT THICKEN. (It is unsafe to use thickening agents in canning. Remember – follow the rules: follow the recipe.)

Fill the Jars

1. Ladle hot chili mixture into clean pint jars.
2. Remove bubbles with the plastic stick and measure one inch headspace.
3. Wipe rims with a damp paper towel.
4. Place lids on the jars and tighten rings finger tight.
5. Process in pressure canner according to the chart below. *Notice the processing time is much longer. This is important to ensure safety of preservation. Do not shorten.*

For more resources, check out the OSU Extension publications on canning at https://extension.oregonstate.edu/mfp/publications.

We would love to see your canning projects, use #mywilcolife on Facebook, Twitter, or Instagram and tag Wilco Stores.

ROBYN ROGERS, THE AUTHOR OF THIS BLOG IS LOCATED ON THE KITSAP PENINSULA IN WASHINGTON AND HER ADVICE IS CONSISTENT WITH THE CLIMATE THERE.