Using a pressure canner can seem intimidating or difficult, but it really isn't once you use it a few times. Follow along for some helpful tips.
Table of Contents:
5. Conclusion
1. Introduction
When we moved here about ten years ago, one of the things we wanted to do was to grow our own fresh fruits and vegetables. But, growing a lot of food means that you're not going to be able to eat all that you grow. That's where food preservation comes in.
2. Reasons for Pressure Canning
There are several ways to preserve food, and canning is an important one. When using a canner, there are two methods to process produce. There is the water bath, or boiling water method, and there is the pressure processing method. There are certain foods like meat, soups, green beans, corn, pumpkin, etc that are considered low acid and they require pressure canning.
Why is that? There is a bacteria called Clostridium botulinum, which exists in most soils, and potentially, in any grown food. These bacteria can produce a toxin that in some cases can kill a person. In a high acid environment, like with pickled vegetables or acidic fruit, botulism poisoning is not likely. But most other foods are low acid and must be processed appropriately.
These bacteria spores can survive the boiling water method used for acidic foods, so pressure processing is required. This high pressure environment enables the cooking temps to be around 240F, which is sufficient in killing any botulinum spores. Alright, if I haven't scared you off from preserving your own food, we will continue.
3. Equipment
Canning food requires a few items, those include:
Pressure canner
Jars, lids and rings
Lid magnet, jar grabber, funnel
Bowls, for food before preparation, and after
Knives, tablespoons and teaspoons, cutting board
Pickling/canning salt (table salt is not recommended), vinegar
Stove, preferably not a ceramic/glass top
Small towels, disposable gloves
Timer of any type, or one on your smartphone/tablet
Canning book, we use the Ball Blue Book Guide to Preserving, this is to determine recipe ingredients, preparation of ingredients, and processing times, among other things
3.1 Our Pressure Canner, And Why We Chose It
There are several types, sizes and brands of pressure canners. Most of you may be familiar with those from your earlier days that used a pressure gauge. They are still made today, and the predominant brands are All American, Mirro and Presto. The type we have, a 16 quart Presto (model number 01745) uses a item called a "pressure regulator" to control the pressure. We usually call it by another technical name, which is a "bobber". LOL.
Here's a pic of the canner, with the bobber installed on the vent pipe:
The reason we picked this type of canner is that those that use a gauge requires it to be calibrated periodically to ensure proper pressures, whereas the bobber is a weighted device and doesn't require calibration. Plus, the bobber works by wobbling back and forth on the pipe vent and makes an audible "pshh-pshh" sound when it's venting steam and working properly.
Compare this to the gauge type canners, which make no such sound and the gauge must be monitored to ensure the proper pressure. So, what's easier, watching TV or reading and hearing the bobber making its sound, or having to get up occasionally and checking a gauge to make sure your processing is running correctly? Some items like corn, takes up to 85 minutes to process, so having to get up every few minutes to check on things can get old in a hurry.
4. Step-by-Step Guide to Using a Pressure Canner
Okay, to verify, these are the steps to use for this particular type of canner, which uses a weighted bobber, not a gauge. If you have such an canner, you will have to refer to your owner's manual.
Depending on what food item you are processing, you will need to refer to your canning book, which will give you some suggestions on how to prepare the food. That may include cutting up the food, pre-cooking it, etc. Any produce will need to be properly washed before preparing. For the sake of time, food preparation will not be covered here.
4.1 Prepare the Jars, Lids and Rings
Prepare your canning jars, lids and rings. We prefer to wash the jars in a sink of hot water, with dish soap and a bit of bleach, you want to get the jars as clean as possible. Use a small wash rag to get inside the jars to clean them. There are some items like a jar cleaning brush which work really well. If the jar is used, it may have some old rust or other stains, especially around the rim area. We use a wire pot cleaner to get rid of such stains. After done cleaning the jars, rinse thoroughly with clean tap water to remove any residues and any bleach. Give the jar a sniff to make sure it doesn't have any bleach smell. Set the jars aside on a clean towel to dry.
You can also clean your lids and rings in the same manner. If the rings are being re-used, you may also have to scrub them to remove any rust or other stains. The lids must be brand new, you should never re-use canning lids. I know there are so-called re-usable lids, but we just prefer to use new ones. Rinse the lids and rings in tap water and place them in a pan with some water in it, and place on a stove burner to heat up. You don't want to boil the lids as that may deform the rubber seals, just a low heat will suffice.
4.2 Prepare the Canner
Place your canner on the stove, preferably one with a larger heating element, which sits slightly above the surface of the stove top. Canners shouldn't be used on flat, ceramic/glass type stoves because the weight of a loaded, hot canner can damage the stove top surface.
For any type of canning, you want to make sure there is some kind of tray on the bottom of the canner, this keeps the jars up off the bottom of the canner and helps diffuse the intense heat of the burner. On our canner, the are small hatch marks on the inside wall. For pressure canning, you want to add enough water to to hit the first hatch mark, which in the case of our canner is about 3 quarts. It may not seem enough to cook 7 quart jars of food, but remember, we're about pressurization, plus higher than boiling temperatures to kill any possible bacteria spores. Turn on the burner to medium heat, and add just a little splash of vinegar to the water, which will help prevent any spotting on the outsides of the jars. Place a small dish towel on the stove next to, but not touching the burner, this helps keep any water from flowing to other parts of the stove top.
Our canner uses a lid with a rubber seal on the inside rim, make sure the seal is free of any damage or nicks before use. On this particular lid, you want to ensure that the vent pipe isn't loose, and that it is clean of any debris. I like to hold it up to a light to verify this. There is also a metal pressure valve that should be checked for looseness and tightened if necessary. And finally there is a small rubber pressure relief valve that should be inspected to verify that it is securely installed in the lid.
4.3 Filling and Loading the Jars Into the Canner
Okay, hang in there, we're almost ready to start, there's just a few more things to do. We've prepared the jars, lids, rings, and canner, the only thing left to do is loading up your food into the jars, and then into the canner. Referring to your canning guide, fill up your jars, using some kind of canning funnel. Depending on the item being processed, the jars should be filled either an inch or half inch from the top. After you're satisfied with this step, you can add any canning salt to the jars, if noted in the instructions. This step isn't necessary, it's a personal preference. After this, take a clean paper towel and clean off the rims of the jars to remove any debris that may interfere with the metal lid sealing on the jar. Take your lid magnet, grab a lid from the pot of warm water, and center it onto the jar lid. Then grab a jar ring, place it over the lid and tighten it down onto the jar. Don't tighten excessively, just enough to secure the ring onto the jar. Its purpose is to hold the lid down while processing.
Alright, you are ready to add the jars to the canner. Using you jar grabbers, grasp the jars under the jar rings and lower the jars into the canner, continue until the canner is filled. In the case of our 16 quart Presto, you can pressure can 7 quarts or 10 pints or 12 half pints. Take the lid, lower it onto the canner at the appropriate place. The lid is slotted in such a way so it will fit only a certain way onto the canner, where it fits flush down onto the top of it. Once the lid is in the right grooves, you will need to rotate it until it locks into position. This is where the black handles of the lid will meet up with the black handles of the canner, it shouldn't go any further. Pressing down on the lid while rotating it into position will help it seal better, and prevent excess water leakage.
Here is a pic of how the lid fits onto the canner top. Notice the arrows which indicate how to lock and unlock the lid:
Take the weighted bobber, and depending on your altitude, and place the appropriate number of weighted rings on it. This ensures the proper pressure. Refer to your canning guide, but at our location, below 1,000 feet, 10 pounds of pressure is usually required. This means one ring is added to the bobber. Above 1,000 feet, you need to process at 15lb, which require another weight ring. Set the bobber aside until later in the process.
This pic shows the bobber with and without the weight ring. One ring is used for 10lb of pressure:
4.4 Processing the Food
Turn up the burner heat control, we usually have to set it to its highest setting to get things going. You will have to experiment to see what setting is right for you. I usually like to have the water in the canner close to boiling before the jars are added, and lid secured.
Once these steps have been done, you must wait for a while until you see a steady stream of steam venting out the top of the vent pipe. When the steam is consistently steady, set your timer for 10 minutes. This time is used to vent any excess pressure. You might also notice that the pressure lock valve is venting a bit of steam and/or water, this is normal. Before the 10 minutes is up, this valve may push up and lock into position, again, this is normal.
Here is a pic of the pressure lock in the "up' position:
After the 10 minutes is up, place the weighted bobber onto the vent pipe. It should sit on the pipe straight, and not crooked. You will again have to wait a while for several minutes, until you see and hear the bobber starting to wobble back and forth, while venting a small amount of steam. You will hear a "pish-pish-pish" type of sound as the bobber vents the steam. Once this sound is consistent, you can back off the heat a little while still maintaining a consistent wobble. At this point, you can start your processing time countdown. For sweet corn, for example, the processing time is 85 minutes for quarts, and 55 minutes for pints.
Here's a pic of the bobber on the vent pipe:
So, while you wait for the processing time to finish, you can go take a break, while still listening to the sound of the bobber venting steam. After the time is up, turn off the heat source, and using oven mitts, carefully move the loaded canner off the burner. I usually place it onto more mitts on my counter next to the stove. Be careful, as the canner is obviously hot, and do not disturb or remove the bobber. The pressure lock will also still be in the up position as there is still high pressure inside the canner. Do not disturb this either.
You must wait for the pressure in the canner to drop as well as the temperature, this can take up to 30 minutes or more. The only way to ensure this is to wait until the pressure lock drops down. After 5 minutes, you can then remove the bobber, and remove the lid, being careful to open lid away from you to avoid any escaping steam. Let the canner sit for another 10 minutes to allow the jars to adjust to room temperature.
You can now remove the jars from the canner using your jar grabber. Place the hot jars on a solid surface on a towel to cool. You may hear a popping noise, which indicates that the lid is sealing onto the jar. The other lids may look like they are up in the center, which indicates they haven't sealed. Don't push down on the lids, just let them seal on their own. Sometimes you won't hear the lids seal, but that doesn't mean that it hasn't happened.
Let the jars sit for at least 12 hours to cool and seal. If I've done canning in the afternoon, I usually let them sit overnight. The next day inspect the lids to verify they have sealed. First check to see if the center of the lid has been pulled down. Second, remove the ring, and give the edge of the lid a very light tug, it should not come loose or pop up. If either of these two things happen, the jar has not sealed, and the food will need to be refrigerated and consumed soon. If the jar has sealed, you can take a wet wash rag and gently clean the jar and lid of any residues.
After the jars are dry, label the lids with the name of the item canned and date with a sharpie or any other permanent marker. Your jar is now ready for storage. I usually leave the rings off as the lids have sealed to the jar. In fact, leaving the rings on can mask a loose lid if it becomes unsealed over time.
5. Conclusion
Congratulations, you have completed your pressure canning adventure! Yes, there's a lot to digest here, but once you do it a few times, it gets easier and less intimidating. I hope this guide has been a great benefit to you.