Learning how to can soup with a pressure cooker is a fantastic way to preserve homemade meals for your pantry. Canning soup safely requires a pressure cooker to achieve the necessary high temperature. This guide walks you through the essential steps for preservation, from choosing your recipe to storing your jars.
Pressure canning is the only safe method for canning low-acid foods like soup. It uses steam under pressure to reach temperatures high enough to destroy botulism spores. This process ensures your canned goods remain safe to eat for up to a year or more.
We will cover everything you need to get started. You’ll learn about required equipment, soup preparation, the step-by-step canning process, and crucial safety tips. Let’s begin with the tools you must have before you start.
how to can soup with a pressure cooker
This main section details the complete procedure. Before you begin, ensure you have all your equipment ready and your soup prepared according to a tested recipe.
Essential Equipment for Pressure Canning Soup
You cannot safely can soup without the right tools. Using improper equipment, like a water bath canner or an electric multi-cooker set to “canning” mode, is dangerous for low-acid foods. Here is what you need.
The Pressure Canner
You must use a dial-gauge or weighted-gauge pressure canner designed for home canning. A standard pressure cooker is not the same thing and is not recommended for this process. Ensure your canner is large enough to hold at least four quart jars upright.
- Dial-gauge canner: Has a dial that shows the exact pressure inside. This gauge must be tested for accuracy annually.
- Weighted-gauge canner: Uses a weighted regulator that jiggles or rocks to maintain pressure. It is less precise but doesn’t require gauge testing.
Canning Jars and Lids
Only use mason jars designed for home canning. Do not reuse jars from store-bought pasta sauce or other products.
- Jars: Use standard pint or quart mason jars. Check each jar for nicks or cracks before use.
- Lids: You need new, flat lids every time you can. The sealing compound must be intact. Bands can be reused if they are not rusty or bent.
Other Necessary Tools
- A large pot or kettle for heating extra water.
- A jar lifter for safely handling hot jars.
- A canning funnel to fill jars cleanly.
- A bubble remover or non-metallic utensil.
- Clean cloths and paper towels.
- A magnetic lid lifter is helpful but optional.
- A timer and a clock.
Preparing Your Soup for Canning
Not every soup recipe is safe for canning. You must follow research-tested guidelines to ensure proper acidity and heat penetration. Thickened soups, soups with dairy, and those containing pasta or rice are generally not recommended for home canning.
Choosing a Safe Recipe
Always use a recipe from a reliable, up-to-date source like the National Center for Home Food Preservation or the USDA. These recipes specify exact ingredients, proportions, and processing times. Do not alter ingredients like onions, celery, or meat ratios, as this can affect safety.
Ingredients to Avoid or Limit
- Dairy, Cream, or Milk: These separate and curdle under high heat.
- Flour, Cornstarch, or Other Thickeners: They prevent proper heat penetration. Can your soup base without thickeners and add them when you reheat the jar.
- Pasta, Rice, Barley, or Noodles: These starches absorb liquid and can become mushy. They also expand, which can affect jar seals. Add them fresh when you heat the soup to serve.
- Excess Fat: Skim fat from broths and meats to prevent seal failures.
Pre-Cooking the Soup
Your soup should be fully cooked before it goes into the jars. This is not the time for slow simmering; you are preparing the product for processing.
- Prepare your soup according to the tested recipe.
- Keep the soup hot (simmering) while you prepare your jars and canner. Do not let it cool.
- If your recipe includes vegetables like potatoes, cut them uniformly so they cook evenly during processing.
Step-by-Step Canning Process
Now, let’s walk through the actual canning procedure. Read through all steps before you begin. The process requires focus and should not be rushed.
Step 1: Prepare the Canner and Jars
Place the rack in the bottom of your pressure canner. Add the amount of water specified in your canner’s manual, usually 2 to 3 inches. Place the canner over low heat to start warming. Do not put the lid on yet.
Wash your jars, lids, and bands in hot, soapy water. Rinse well. Place the jars in a separate pot of hot water to keep them warm until filling. Heat the flat lids in a small pan of hot (not boiling) water to soften the sealing compound.
Step 2: Fill the Jars with Hot Soup
This step is called “hot packing.” Work with one jar at a time, keeping the others in the hot water.
- Remove a hot jar from the water using your jar lifter.
- Place the canning funnel on the jar.
- Ladle the hot, simmering soup into the jar, leaving a 1-inch headspace at the top. This space is critical for forming a vacuum seal.
- Run your bubble remover around the inside of the jar to release trapped air bubbles.
- Check the headspace again and add more soup if needed.
- Wipe the jar’s rim with a clean, damp cloth to ensure no food particles interfere with the seal.
- Place a hot flat lid on the rim, then screw on the band until it is “fingertip tight”—just until you feel resistance. Do not overtighten.
Step 3: Process the Jars in the Pressure Canner
Carefully place the filled jars onto the rack in the warm canner using the jar lifter. Do not let the jars touch each other or the sides of the canner. Once all jars are in, ensure the water level is as per your manual. If needed, add more hot water.
Place the lid on the canner and lock it according to the manufacturer’s instructions. Leave the weight off or the petcock open. Turn the heat to high. Allow steam to vent steadily from the vent port for 10 full minutes. This step removes air from the canner.
After 10 minutes of venting, place the weight on the vent port or close the petcock. The canner will now begin to pressurize.
Step 4: Maintain Pressure and Time the Process
Watch the dial gauge or listen for the weight to begin jiggling or rocking. When the correct pressure is reached (usually 10 or 11 pounds, depending on your altitude and canner type), start your processing timer.
Adjust the heat under the canner to maintain a steady, consistent pressure for the entire processing time. This time is specified in your recipe and is typically 75 minutes for quarts of vegetable-based soup or 90 minutes for soups with meat. Do not let the pressure drop during this period.
Step 5: Cool and Depressurize the Canner
When the processing time is complete, turn off the heat. Let the canner cool naturally and depressurize on its own. Do not try to cool it quickly with water or by moving it. This can take 30 to 45 minutes.
Do not open the canner or remove the weight until the pressure gauge reads zero. After it is fully depressurized, wait an additional 10 minutes. Then, unlock and carefully remove the lid, tilting it away from you to avoid steam.
Step 6: Remove and Cool the Jars
Using the jar lifter, carefully remove the jars and place them upright on a towel or cooling rack, leaving at least an inch of space between them. You may hear a “ping” sound as the jars cool and the lids seal. Do not tighten the bands at this stage.
Let the jars cool undisturbed for 12 to 24 hours. After they have cooled completely, check the seals by pressing the center of each lid. If it is firm and does not flex up and down, the jar is sealed. Any unsealed jars must be refrigerated and used promptly.
Remove the bands, wash the jars, label them with the contents and date, and store in a cool, dark place.
Critical Safety Tips and Common Mistakes
Safety is the most important part of learning how to can soup with a pressure cooker. Ignoring these guidelines can lead to spoiled food or serious illness.
Altitude Adjustments Are Mandatory
Water boils at a lower temperature at higher altitudes. This means you must increase your processing pressure to compensate. If you do not, your food will be under-processed.
- For dial-gauge canners, add 1 pound of pressure for every 2,000 feet above sea level.
- For weighted-gauge canners, use the 15-pound weight at altitudes above 1,000 feet.
- Always check a reliable altitude chart for your exact location.
Never Skip the Venting Step
Venting the canner for a full 10 minutes before pressurizing is non-negotiable. This removes air pockets that can lower the temperature inside the canner, resulting in unsafe processing. Set a timer and do not shorten this step.
Using Outdated or Unsafe Methods
Canning recommendations have changed over time as science has improved. Do not use methods from old cookbooks or family recipes that contradict current guidelines.
- Do not can soup in an oven, dishwasher, or microwave.
- Do not use the “open-kettle” method (pouring hot food into jars and letting it seal).
- Do not add extra starch, dairy, or untested ingredients to your soup before canning.
Ignoring Signs of Spoilage
Before opening any jar for use, inspect it. Do not consume the contents if you observe any of the following:
- A broken or bulging lid.
- Bubbles rising in the jar.
- Spurting liquid when opened.
- An off odor, mold, or discoloration.
- If in doubt, throw it out.
Troubleshooting Common Issues
Even experienced canners encounter problems. Here are solutions to frequent issues.
Jars That Did Not Seal
If a jar fails to seal, you can often reprocess it within 24 hours. Check the rim for nicks, use a new lid, and repeat the entire canning process. Alternatively, refrigerate the jar and use the soup within a few days.
Siphoning (Liquid Loss from Jar)
This is when liquid leaks out during processing, which can sometimes prevent a seal. It can be caused by rapid temperature or pressure changes, overfilling jars, or not allowing the canner to depressurize naturally. Ensuring steady heat and proper cooling can minimize this.
Cloudy Liquid or Darkened Vegetables
Cloudiness can be caused by minerals in hard water or starch from certain vegetables. Darkening usually happens when vegetables are exposed to air before processing. Using fresh ingredients and following the hot pack method closely can help.
FAQs About Canning Soup with a Pressure Cooker
Here are answers to some common questions about pressure canning soup.
Can I can any type of soup?
No, you cannot. You should only can soups that follow tested recipes from authoritative sources like the USDA. Soups with dairy, cream, thickeners, pasta, rice, or noodles are not safe for home canning. These ingredients can prevent proper heat penetration or break down during processing.
What is the difference between a pressure cooker and a pressure canner?
A pressure cooker is designed for fast cooking of food for immediate consumption. A pressure canner is built to process jars for long-term storage. It is larger, has a rack for jars, and is calibrated to maintain precise pressures for extended times. For safety, you must use a proper pressure canner.
How long does home-canned soup last?
For best quality, use your home-canned soup within one year. Properly processed and sealed jars are safe for much longer if stored in a cool, dark place, but flavor and texture will degrade over time. Always check for signs of spoilage before use.
Can I double a soup recipe for canning?
You can scale up a tested recipe, but be cautious. The key is to maintain the same proportions of ingredients, especially the ratio of solid ingredients to broth. Do not make the soup thicker. Always process the jars for the full time required by the original recipe, regardless of batch size.
Why is my soup mushy after canning?
Vegetables will always be softer after the high-heat pressure canning process compared to fresh cooking. To minimize mushiness, cut vegetables into uniform, large chunks and avoid overprocessing. Using a tested recipe ensures you are not processing longer than necessary.