How to Use a Pressure Canner
If you want to preserve low-acid foods like vegetables, meats, beans, and broth, learning how to use a pressure canner is essential.
This guide explains the full process clearly, so you can can safely, confidently, and with better results.
What a Pressure Canner Does
A pressure canner is not the same as a pressure cooker.
It is a specialized home canning tool designed to reach and maintain temperatures high enough to destroy harmful microorganisms, including Clostridium botulinum, in low-acid foods.
Because these foods do not have enough natural acidity to prevent dangerous bacterial growth, a boiling-water canner is not safe for them.
Pressure canning creates a sealed environment that allows the temperature inside the canner to rise above 212°F, which is the boiling point of water at sea level.
That higher temperature is what makes safe preservation possible for foods such as green beans, carrots, corn, chicken, beef, fish, and soups.
Before You Start: Equipment and Safety Checks
Before you process any jars, verify that your pressure canner is complete and working properly.
The exact setup varies by brand, but most canners include a lid, gasket or sealing ring, vent pipe, pressure regulator, jars rack, and a pressure gauge or weighted gauge.
Check these items first
- Gasket or sealing ring: Make sure it is flexible, not cracked, and seated correctly.
- Pressure gauge: Ensure dial gauges are tested regularly if your model uses one.
- Vent pipe: Confirm it is clear of debris.
- Weighted gauge or regulator: Verify it matches your canner model and required pressure.
- Jars and lids: Use approved canning jars with two-piece lids in good condition.
Always consult the manufacturer’s instructions for your specific model, and use tested recipes from reliable sources such as the USDA, National Center for Home Food Preservation, or your local Cooperative Extension office.
How to Prepare Food and Jars
Safe pressure canning begins with proper food preparation.
Start with fresh, high-quality ingredients and follow the recipe exactly.
Do not increase the amount of vegetables, change the cut size, or add thickeners unless the recipe specifically allows it.
Wash and trim produce carefully.
For meats, remove excess fat when the recipe calls for it.
For beans, soak or precook only if the recipe says to do so.
Fill jars according to the tested headspace requirement, which is the empty space between the food and the lid.
General jar preparation steps
- Wash jars in hot soapy water or keep them hot in a dishwasher or simmering water.
- Inspect jars for chips or cracks.
- Use new lids each time.
- Follow the recipe for headspace exactly.
- Remove air bubbles with a nonmetallic utensil if directed.
- Wipe jar rims clean before applying lids.
How to Use a Pressure Canner Step by Step
Once the jars are filled and the canner is ready, the process is straightforward, but timing and pressure control matter.
Work carefully and do not rush the venting or pressurizing stages.
1. Add water to the canner
Most pressure canners require a specific amount of water, often 2 to 3 inches, though the exact amount depends on the model.
Use the amount recommended in the manufacturer’s manual or the recipe.
2. Load the jars
Place filled jars on the rack inside the canner so they do not touch each other or the sides.
The rack keeps jars off the bottom and allows steam circulation.
3. Lock the lid
Close the lid securely according to your canner’s instructions.
If the canner uses a gasket, confirm the seal is properly seated.
4. Heat and vent the canner
Turn the burner to high heat until steam begins to flow steadily from the vent pipe.
Once a strong, continuous column of steam appears, vent the canner for the full time specified in your manual, usually 10 minutes.
This step removes trapped air and helps the canner reach an accurate processing temperature.
5. Build pressure
After venting, place the weighted gauge or close the petcock if your model uses one.
Pressure will rise gradually.
Watch the gauge closely and adjust the heat as needed to maintain the target pressure.
6. Process for the full recommended time
Start timing only when the correct pressure has been reached.
Keep the pressure steady for the entire processing time listed in the tested recipe.
Do not let pressure dip below the required level; if it does, you may need to bring the canner back to pressure and restart timing, depending on the recipe and how long it dropped.
7. Let the canner cool naturally
When processing is complete, turn off the heat and allow the canner to cool on its own.
Do not force-cool it, run cold water over it, or move it until pressure returns to zero naturally.
Sudden cooling can cause liquid loss, jar breakage, or unsafe processing conditions.
8. Remove jars carefully
After pressure is fully released and the canner has cooled, remove the lid by tilting it away from your face to avoid steam burns.
Lift jars with a jar lifter and place them on a towel or cooling rack with space between them.
How to Know the Pressure Is Correct
The required pressure depends on three main factors: the altitude, the type of canner, and whether you use a dial gauge or weighted gauge.
Altitude matters because water boils at a lower temperature at higher elevations, so pressure must be adjusted accordingly.
- Dial gauge canners: Usually require precise pressure settings, such as 11 psi at sea level for some recipes.
- Weighted gauge canners: Typically use fixed settings such as 10, 15, or another specified pressure.
- Altitude adjustments: Recipes may require higher pressure above certain elevations.
Always check a tested chart for the exact adjustment your recipe requires.
Never guess at pressure or processing time.
Common Mistakes to Avoid
Many home canning problems come from small errors that affect safety or seal quality.
Avoid these common mistakes when learning how to use a pressure canner:
- Using recipes from unverified blogs or social media.
- Changing ingredients, proportions, or jar sizes.
- Failing to vent the canner long enough.
- Letting pressure drop too low during processing.
- Overfilling jars or ignoring headspace instructions.
- Using old, damaged, or nonapproved lids.
- Moving the canner while it is pressurized.
- Force-cooling the canner to save time.
What Foods Can You Pressure Can?
Pressure canning is intended for low-acid foods.
This includes plain vegetables, meats, poultry, seafood, beans, and many soups.
Some tomato products and salsa recipes may also require pressure canning unless enough acid is added and the recipe is specifically tested for boiling-water canning.
Examples of commonly pressure-canned foods include:
- Green beans
- Carrots
- Potatoes
- Peas
- Chicken
- Beef
- Turkey
- Fish
- Dry beans
- Vegetable stock
Foods like jams, jellies, most fruit, and properly acidified pickles are usually processed in a boiling-water canner instead.
How to Store Pressure-Canned Jars
After jars cool for 12 to 24 hours, check the seals.
The lid should be concave and not flex when pressed in the center.
Remove the screw bands, wash and dry the jars, then label them with the contents and date.
Store sealed jars in a cool, dark, dry place.
Avoid direct sunlight, heat sources, and damp locations.
For best quality, use home-canned foods within 1 year, although properly sealed jars often remain safe longer if stored correctly.
When to Reprocess or Discard a Jar
If a jar did not seal, refrigerate the contents and use them soon, or reprocess them within 24 hours using a fresh lid and the full tested processing time.
Discard any jar that shows signs of spoilage, such as bulging lids, leaking, off odors, mold, or spurting liquid when opened.
When in doubt, throw it out.
Safe pressure canning depends on strict process control, and food safety should always come before saving a jar.
