Canning soup at home is a fantastic way to preserve the flavors of your garden, enjoy homemade goodness year-round, and save money by utilizing seasonal ingredients. It allows you to control the ingredients, avoid unwanted preservatives, and create customized soup recipes that suit your taste. However, safety is paramount when canning, especially with low-acid foods like many soups. This comprehensive guide will walk you through every step of the process, ensuring you create safe and delicious canned soup in glass jars.
Understanding the Basics of Canning Soup
Before diving into the canning process, it’s crucial to grasp the underlying principles. Canning preserves food by creating a vacuum seal that prevents spoilage. This seal is formed by heating the jars, forcing air out, and then cooling them, creating a pressure difference that holds the lid tightly in place.
Two primary canning methods exist: water bath canning and pressure canning. Water bath canning is suitable for high-acid foods like fruits, jams, and pickles. However, soups, particularly those containing meat, poultry, seafood, or most vegetables, are low-acid foods and must be processed in a pressure canner to reach a safe temperature that eliminates the risk of botulism.
Botulism is a serious illness caused by the bacterium Clostridium botulinum, which thrives in low-oxygen environments like improperly canned foods. Pressure canning reaches temperatures of 240°F (116°C) or higher, destroying these harmful bacteria.
Choosing the Right Jars and Lids
Selecting the appropriate jars and lids is essential for successful canning. Use only canning jars designed for home canning. These jars are specifically made to withstand the high temperatures and pressures involved in the canning process. Common brands include Ball, Kerr, and Mason.
Inspect the jars for any cracks, chips, or imperfections, especially around the rim. Damaged jars can break during processing or fail to seal properly.
Use new, flat lids with each canning batch. The sealing compound on the lid ensures an airtight seal. Although rings can be reused, the flat lids are a one-time-use item.
Essential Canning Equipment
In addition to jars and lids, you’ll need a few key pieces of equipment:
- Pressure Canner: This is non-negotiable for canning soup. Ensure your canner is in good working order and that you understand its specific instructions.
- Jar Lifter: A jar lifter is a specialized tool for safely lifting hot jars out of the canner.
- Wide-Mouth Funnel: A wide-mouth funnel helps to pour soup into the jars without spilling.
- Bubble Remover/Headspace Tool: This tool removes air bubbles from the jar and measures the headspace (the space between the top of the food and the lid).
- Clean Kitchen Towels: For wiping jar rims and cleaning up spills.
- Large Stockpot: For preparing the soup.
Preparing Your Soup for Canning
The preparation of your soup is just as important as the canning process itself. Certain ingredients can affect the safety and quality of the final product.
Recipe Considerations and Approved Recipes
It’s crucial to use tested and approved canning recipes from reputable sources like the USDA Complete Guide to Home Canning, the National Center for Home Food Preservation, or reputable extension services. Do not invent your own soup recipes for canning, as ingredient ratios and processing times are critical for safety.
Avoid adding thickeners like flour, cornstarch, cream, milk, or rice before canning. These can interfere with heat penetration and potentially lead to spoilage. Instead, add these ingredients when you reheat the soup for serving.
Adjusting Recipes for Canning
While you should adhere to approved recipes, some minor adjustments are acceptable. You can often reduce the amount of salt or spices to suit your taste. However, never reduce the amount of acid (like vinegar or lemon juice) in recipes that call for it, as acid helps to preserve the food.
Ingredient Selection and Preparation
Use fresh, high-quality ingredients. Select vegetables that are at their peak ripeness. Wash all produce thoroughly.
Cut vegetables into uniform sizes to ensure even cooking during processing.
Meats and poultry must be fully cooked before adding them to the soup for canning. Raw meats can increase the risk of spoilage.
Addressing Specific Ingredients
- Beans: Dry beans must be fully rehydrated and cooked before adding them to the soup.
- Pasta and Rice: As previously mentioned, avoid adding pasta or rice before canning. They can become mushy and affect heat penetration.
- Dairy Products: Never add milk, cream, cheese, or other dairy products to soup before canning. They can curdle and spoil.
The Canning Process: Step-by-Step
Now, let’s move on to the detailed canning process. Follow these steps carefully to ensure a safe and successful outcome.
Step 1: Preparing the Jars and Lids
Wash the jars thoroughly in hot, soapy water. Rinse them well.
Sterilize the jars by simmering them in hot (180°F / 82°C) water for 10 minutes. Keep the jars hot until you are ready to fill them. This can be done in the canner itself, if desired.
Place the new lids in a small saucepan and cover them with water. Heat the water until it simmers (do not boil) and keep the lids hot until ready to use. This softens the sealing compound and prepares it for a good seal.
Step 2: Filling the Jars
Carefully ladle the hot soup into the hot jars, leaving the recommended headspace. Headspace is the amount of space between the top of the soup and the top of the jar. Generally, 1 inch of headspace is recommended for soups. Refer to your specific recipe for exact headspace requirements.
Use a bubble remover tool to gently release any trapped air bubbles from the soup. Insert the tool along the sides of the jar and move it up and down to dislodge bubbles.
Wipe the jar rims with a clean, damp cloth to remove any food residue. This ensures a proper seal.
Center the lid on the jar and screw on the band fingertip tight. Do not overtighten the band, as this can prevent air from escaping during processing.
Step 3: Loading the Pressure Canner
Follow the manufacturer’s instructions for your specific pressure canner model.
Place the canning rack in the bottom of the canner. Add the amount of water specified in your canner’s instructions. This is typically 2-3 inches.
Carefully load the filled jars into the canner, ensuring they do not touch each other or the sides of the canner.
Step 4: Processing the Soup
Secure the lid of the pressure canner according to the manufacturer’s instructions.
Turn the heat to high and vent the canner by allowing steam to escape for the specified amount of time (usually 10 minutes). This purges the air from the canner.
Close the vent and allow the pressure to build to the level specified in your recipe. The required pressure depends on your altitude. It is essential to adjust processing times and pressure for your altitude.
Once the desired pressure is reached, maintain that pressure consistently for the entire processing time. Fluctuations in pressure can affect the safety of the canned soup.
Start timing the processing from the moment the pressure gauge reaches the required level.
Step 5: Cooling and Depressurizing
After the processing time is complete, turn off the heat and allow the canner to cool naturally. Do not force cool the canner, as this can cause the jars to break or the seals to fail.
Wait until the pressure gauge returns to zero before carefully opening the vent.
Wait an additional 10 minutes before removing the lid of the canner. Open the lid away from your face to avoid steam burns.
Step 6: Removing and Cooling the Jars
Use a jar lifter to carefully remove the hot jars from the canner. Place them on a towel-lined surface, leaving space between the jars to allow for air circulation.
Do not disturb the jars while they are cooling. Avoid tightening the bands or touching the lids.
Allow the jars to cool completely for 12-24 hours.
Checking for Seals and Storing Your Canned Soup
After the jars have cooled completely, check for a proper seal. The lid should be concave (curved downwards) and should not flex when pressed in the center.
You can also check the seal by removing the band and lifting the jar by the lid. If the lid stays firmly attached, the jar is properly sealed.
If any jars did not seal, you have two options:
- Refrigerate the soup immediately and use it within a few days.
- Reprocess the soup using new lids. Make sure to follow the canning instructions carefully.
Remove the bands from the sealed jars. This prevents moisture from accumulating and causing rust.
Wash the jars to remove any residue.
Label each jar with the date and contents.
Store the canned soup in a cool, dark, and dry place. Properly canned soup can be stored for up to a year.
Troubleshooting Common Canning Problems
Even with careful preparation, problems can sometimes arise during canning. Here are some common issues and their solutions:
- Jars Break: Use only canning jars, avoid temperature shocks, and ensure proper venting during processing.
- Seals Fail: Use new lids, ensure clean jar rims, and follow processing times and pressures accurately.
- Siphoning (Loss of Liquid): Avoid overfilling jars, maintain consistent pressure during processing, and allow the canner to cool naturally.
- Cloudy Broth: This can be caused by minerals in the water or starch from vegetables. It does not necessarily indicate spoilage, but using filtered water can help.
Altitude Adjustments for Safe Canning
Altitude plays a critical role in canning, as water boils at lower temperatures at higher altitudes. This means that you need to adjust processing times or pressures to ensure the food reaches a safe temperature to kill harmful bacteria.
Refer to your pressure canner’s instructions or the USDA Complete Guide to Home Canning for specific altitude adjustments. The following table provides a general guideline for pressure adjustments:
| Altitude (Feet) | Dial Gauge Canner (PSI) | Weighted Gauge Canner (PSI) |
|——————-|————————–|—————————–|
| 0-1,000 | 11 | 10 |
| 1,001-2,000 | 12 | 15 |
| 2,001-4,000 | 13 | 15 |
| 4,001-6,000 | 14 | 15 |
| 6,001-8,000 | 15 | 15 |
| 8,001-10,000 | 16 | 15 |
Note: Always consult your pressure canner’s manual and approved canning recipes for the most accurate altitude adjustments.
Enjoying Your Home-Canned Soup
When you’re ready to enjoy your home-canned soup, inspect the jar before opening it. Check for any signs of spoilage, such as bulging lids, unusual odors, or mold growth. If you notice any of these signs, discard the soup immediately.
Heat the soup thoroughly to a rolling boil for at least 10 minutes before serving. This ensures that any remaining bacteria are killed.
Now, savor the delicious and rewarding taste of your homemade, safely canned soup!
What types of soup are safe to can at home?
Safety is paramount when canning soup. Soups that contain low-acid ingredients such as meat, poultry, seafood, dairy, and most vegetables (excluding tomatoes and pickled vegetables) MUST be pressure canned. These ingredients are susceptible to botulism spores, which can only be killed by the high temperatures reached during pressure canning. It’s crucial to follow tested recipes and guidelines from reputable sources like the USDA or your local extension office to ensure safe processing times and pressures based on your altitude.
Soups primarily composed of high-acid ingredients, such as tomato-based soups with added acids (lemon juice or vinegar), can be safely processed in a boiling water bath canner. However, always err on the side of caution. If you’re unsure about the acidity of an ingredient or a specific recipe, it’s always best to pressure can it. Remember, safety should be your top priority when preserving food at home.
What equipment do I need to safely can soup?
To safely can soup, you’ll need several essential pieces of equipment. A pressure canner is required for low-acid soups; ensure it’s in good working condition and that the pressure gauge is accurate. For high-acid soups, a boiling water bath canner with a rack is sufficient. You’ll also need canning jars (pint or quart), new canning lids, canning rings, a jar lifter, a wide-mouth funnel, and a bubble freer/headspace measuring tool.
Beyond the core equipment, consider a large stockpot for cooking the soup, a ladle for filling jars, clean kitchen towels, and a timer. Properly preparing and maintaining your equipment is crucial for successful and safe canning. Always inspect jars for chips or cracks and ensure lids are new to achieve a proper seal. Having all your equipment organized beforehand will make the canning process smoother and more efficient.
How do I prepare my canning jars and lids?
Proper preparation of canning jars is essential for creating a vacuum seal. Start by washing jars thoroughly in hot, soapy water, rinsing well. Then, sterilize them by placing them in a boiling water bath canner, completely submerged, and boil for 10 minutes (add 1 minute for every 1,000 feet above sea level). Keep the jars hot until you are ready to fill them with the hot soup.
For lids, follow the manufacturer’s instructions. Modern lids typically only require washing in hot, soapy water and rinsing. You no longer need to simmer them in hot water. Keeping the lids clean and at room temperature is sufficient. Ensure the sealing compound is intact and free of defects. Using clean, properly prepared jars and lids increases the likelihood of a successful and safe canning process.
What is headspace, and why is it important?
Headspace refers to the empty space between the top of the food in the jar and the lid. This space is crucial for creating a proper vacuum seal during the canning process. As the jars cool, the air in the headspace is forced out, creating a vacuum that seals the lid to the jar. Insufficient headspace can lead to food spoilage, while excessive headspace can prevent a proper seal from forming.
The recommended headspace for canning soup is typically 1 inch. Use a headspace measuring tool or a clean ruler to ensure you leave the correct amount. After filling the jars, remove any air bubbles using a bubble freer or non-metallic spatula, and then wipe the jar rims clean with a damp cloth before applying the lid and ring. Accurate headspace is critical for safe and long-term food preservation.
How do I pressure can soup safely?
Pressure canning is essential for preserving low-acid soups safely. First, fill the prepared jars with hot soup, leaving the recommended headspace. Remove air bubbles and wipe the jar rims clean. Place the lids and rings on the jars, tightening them fingertip-tight. Place the jars in the pressure canner, ensuring they don’t touch each other. Add the amount of water specified in your canner’s instructions.
Secure the lid of the pressure canner and follow the manufacturer’s instructions for venting the canner and bringing it up to the correct pressure. Maintain the recommended pressure for the specified processing time, adjusting for your altitude. Once the processing time is complete, turn off the heat and allow the canner to cool naturally until the pressure returns to zero. Carefully remove the jars with a jar lifter and place them on a towel-lined surface to cool completely. Avoid disturbing them for 12-24 hours.
How do I know if my canned soup has sealed properly?
After the jars have cooled completely (usually 12-24 hours), check for a proper seal. Press down on the center of the lid. If it doesn’t flex or pop, the jar is sealed. You can also remove the ring and lift the jar gently by the lid only; a properly sealed lid will remain firmly attached. Another indicator is a concave (slightly indented) lid.
If any jars haven’t sealed, you have a few options. You can reprocess them within 24 hours using new lids and following the original processing instructions. Alternatively, you can refrigerate the unsealed soup and use it within a few days. It is unsafe to store unsealed jars at room temperature. Discard any jar with signs of spoilage, such as bulging lids, unusual odors, or discoloration.
How long can I safely store home-canned soup?
When properly canned and sealed, home-canned soup can be safely stored for at least one year, and potentially longer. However, for optimal quality and flavor, it’s best to use it within a year. Store canned soup in a cool, dark, and dry place. Avoid storing jars in areas that are subject to extreme temperature fluctuations or humidity.
Before consuming home-canned soup, always inspect the jar for signs of spoilage, such as bulging lids, leaks, or unusual odors. If you notice any of these signs, discard the contents without tasting. As an extra precaution, it’s recommended to boil home-canned soup for 10 minutes before consumption, especially for low-acid soups processed in a pressure canner. This boiling step further reduces the risk of botulism.