Canning 101: How to Use a Pressure Canner

pressure canner instructions
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Any discussion about pressure canning must first begin with the question: "Why do I need a pressure canner?" For canning purposes, food can be divided into two groups: Low acid and high acid. High acid foods (which include fruits and pickled foods) are safe to can in a water bath canner. (Learn about water bath canning here.) Low acid foods (which include meat and non-pickled vegetables) must be processed at 250 degrees F. in order to kill off dangerous micro-organisms. Because water bath canners only reach a top temperature of 212 degrees F., they cannot kill off those micro-organisms, no matter how long you boil the food or process it in the canner. Therefore, a pressure canner, which can easily reach 250 degrees F. internally, is necessary for safely canning low acid foods. (To learn more about the importance of pressure canning low acid foods, please see "What You Need to Know About Botulism.")

It's extremely common for people to feel afraid of pressure canners. I admit, when I first used one (over a decade ago), I was completely intimidated by all the gauges and vents. It didn't take me long to realize, however, that pressure canning was really no more difficult than water bath canning. And if you're afraid your pressure canner is going to explode - don't be. If you stick to the top brands (Presto and All American), they are sturdy suckers with lots of safety features. They will not explode, unless (as the Boston Marathon bombers did) you try to make them do so!

If you're just starting out in pressure canning and don't want to invest a lot of money, I suggest buying a 23-quart Presto pressure canner. It works great! You should also buy an extra rack so you can double stack pint jars inside the canner - and I recommend buying a rocker gauge so you don't have to worry about the accuracy of the dial gauge that comes with the canner. (Please see this post for complete information on these features, and for a thorough comparison of Presto and All American pressure canners.)

Do also note that there is a difference between pressure cookers and pressure canners. Some manufacturers of pressure cookers like to say you can pressure can in them, but that is not safe. For more on this topic, please see "Pressure Canners vs. Pressure Cookers" and "Can I Use My Instant Pot Pressure Cooker for Canning?"

What You Will Need:
A pressure canner (not a pressure cooker!)
Canning jars
Canning lids and screw bands (Lids can't be reused, but screw bands can; new jars come with both lids and screw bands.)
Jar lifter
Plastic or wooden-handled utensil
Cooling rack or bath towel

Plus, whatever you'll need to prepare the food you're canning, like a knife and cutting board

How to Use a Pressure Canner:

1. Begin by inspecting your pressure canner's lid. Using the manufacturer's guidelines, check all the vents to ensure nothing (like food particles) is blocking them.

2. Wash the canning jars, lids, and screw bands. Jars do not need to be sterilized before canning. The canning process itself will sterilize them. (For more on this topic, click here.)

3. Fill the pressure canner with water, according to the manufacturer's directions. With the Presto, there's a line on the side of the canner to show how high the water should reach.

4. Place the prepared canning jars inside the canner, sans lids and screwbands. Place the canner on a large burner, over medium-high heat. (The idea here is to slowly warm the jars, so they don't break from heat shock.)

5. Prepare food according to a trusted recipe. My preferred source is the Ball Complete Book of Home Preserving, but other safe sources are The Ball Blue Book, the Ball website, and The National Center for Home Food Preservation website. Canned food can spoil or cause serious illness if you use a recipe that's not tested safe for home canning.

6. Using a jar lifter, remove one empty jar from the canner. Fill it with food. The recipe will tell you how much "headspace" (i.e. space between the top of the food and the top of the jar) is necessary.
Beans should be pressure canned. Here, I'm filling a jar with rehydrated lima beans.
7. Using a wooden or plastic handle (from a spoon, spatula, or some other utensil), remove any bubbles from the jar. Use an up and down (not round and round motion). Do not use a metal utensil because it may damage glass jars.

8. Wipe the rim of the jar with a clean, damp towel. Putting a bit of white vinegar on the towel will do an excellent job getting that rim really clean - the first step toward getting a good seal on the jar.

9. Put a lid on top of the jar.

10. Place one screw band on top of the jar. Screw the band in place until you just begin to feel resistance. Don't screw down hard.

11. Using a jar lifter, place the jar in the canner.

12. Repeat steps 6 through 11 with another jar, until all the food is in jars.
Warm, filled jars in the pressure canner just before processing.
13. Place the lid on the canner and lock it according to the manufacturer's directions. It may take several minutes for the water to boil, but you'll know it's boiling again when steam begins coming out of the vent at the top of the canner. Allow the steam to vent steadily for 10 minutes; see an example of venting in the video below.

14. Place the weight on the vent. (The weight comes with the pressure canner and is a sort of lid for the vent hole. See photo to the left.) If you're using a rocker gauge, use it instead.

15. If your pressure canner has a dial gauge (as shown to the left), wait until the gauge reads 10 pounds pressure before you begin timing how long your food should process. NOTE: If you live above 1,000 feet elevation, you must increase the amount of pressure used. (The processing time does not change; only the pressure changes.) Go here to discover your approximate altitude...and follow these guidelines.

If your canner has a weighted gauge, follow the manufacturer's instructions about how to use it to maintain pressure and time the processing of your food. Below, you can see a video of the rocker gauge on my Presto when the canner is at the appropriate pressure for safe canning.

16. Regulate the heat in the canner by watching the gauge and keeping it at the recommended pressure level. If necessary, turn the burner heat slightly up to increase the pressure level, or turn the heat slightly down to decrease the pressure level. Rapid changes in temperature inside the canner can lead to food siphoning out of the jars, which often leads to seal failures.

17. When the recipe's specified processing time is up, turn off the burner and let the canner cool. Do NOT remove the lid. Do NOT remove the vent weight. Do NOT place a damp towel or cold water on the canner, hoping to cool it faster.

18. When the canner gauge reads zero, let the canner sit an additional 5 minutes. Remove the vent weight. Unlock and remove the canner lid, letting the steam in the canner escape in the opposite direction from your face and body. (HINT: The lid should come off easily; if it doesn't, give the canner another few minutes to sit, then try again.) Allow the jars to sit in the open canner for 10 minutes.

19. Remove the jars, one at a time, using a jar lifter. Place them on a strong cooling rack or on a towel placed atop your kitchen counter. Make sure that as you move the jars, you keep them upright. At this time, don't try to wipe off the jars or lids because this may prevent the lids from sealing properly.
Pressure canned lima beans, cooling.
10. Allow the jars to cool, untouched and undisturbed, for 24 hours.

21. After 24 hours, check to see if the lids have sealed: Press down on the center of each lid; a properly sealed jar lid will not move.

22. Be sure to write the contents and the date on each jar's lid.