Canning tomatoes is a fantastic way to preserve your garden's bounty, but it can sometimes be problematic.
Here are troubleshooting tips to help you understand why canned tomatoes go bad. If you're new to canning, visit our post on "How To Can Tomatoes."
⬇️ Table of Contents
Key Canning Issues To Avoid
- Sterilization is Key: Sterilization of jars and lids is the first line of defense against bacterial contamination. All canning equipment should be sterilized before use. This can be done by boiling the jars and lids or using a dishwasher with a sterilizing cycle.
- Avoiding Cross-Contamination: Always wash your hands thoroughly before handling any canning materials or the tomatoes themselves. Use clean cutting boards and utensils to avoid cross-contamination.
- Monitoring for Spoilage: Be vigilant for signs of spoilage in your canned tomatoes. These can include mold, an off-odor, leakage, or bulging lids. If you notice any of these signs, it’s safest to discard the product.
Chart: Problems with Canned Tomatoes
⬅️ Chart Swipe Left ⬅️
|#1 Loss of Liquid
|Food packed too tightly
|Pack food loosely
|If a good seal is formed, food is still safe
|#2 Seal Breakage
|Underprocessing, crack in jar
|Process properly, use sound jars
|Reprocess if broken seal is detected within 24 hours
|#3 Cloudy Liquids
|Bacterial spoilage, minerals
|Use soft water, proper processing
|Destroy food if microbiological spoilage occurs
|#4 Fermentation & Gas
|Proper processing, avoid open-kettle
|Spoilage typically develops within days after canning
|#5 Bitter Flavor
|Process properly, store cool
|Bacteria may survive canning but remain dormant
|:Reheat food like applesauce to boil
|Mycotoxins from molds can be toxic or carcinogenic
|#7 Darkening After Removal
|Process long enough to inactivate
|Indicates underprocessing, potential safety issue
|#8 Floating Fruit
|Packed too loosely
|Use hot pack, ripe fruit
|: Reheat food like applesauce to boil
|#9 Corroded Lids
|Acid reaction with metal
|Safe unless extensive corrosion or mold presence
|Reaction with minerals or utensils
|Use soft water, avoid certain metals
|Safe unless due to microbial spoilage
Canned Tomatoes Best Practices
Properly Preparing the Tomatoes: Choose firm, ripe tomatoes for canning. Wash them thoroughly and remove any blemishes or damaged areas, as these can harbor bacteria.
Acidity Adjustment: Tomatoes vary in acidity, and sometimes additional acid needs to be added for safe canning. Lemon juice or vinegar can be used to adjust the acidity levels, ensuring that the environment is inhospitable to harmful bacteria.
Following Trusted Recipes: Use recipes from reliable sources, especially if you are a beginner. These recipes have been tested and provide the correct proportions and processing times necessary for safe canning.
Correct Processing Times: Adhering to the specified processing times is crucial. Under-processing can lead to undercooked food that might be unsafe, while over-processing can affect the quality and taste.
Cooling Jars Properly: After processing, allow the jars to cool gradually. Rapid temperature changes can compromise the seal or lead to breakage.
Bisphenol-A (BPA) Risks
BPA in Canned Products: A significant health concern in canned foods, including tomatoes, is the presence of Bisphenol-A, commonly known as BPA. This chemical compound is often used in the lining of metal cans.
Health Impacts: BPA exposure has been linked to several health issues, including hormonal disruptions and increased risk for certain types of cancer. The acidic nature of tomatoes can exacerbate the leaching of BPA, making it a notable concern in canned tomato products.
Proper Tomato Canning Equipment
In addition to understanding common problems in canning tomatoes, it's crucial to be aware of the various types of canning equipment available and their respective benefits. Here's a brief overview:
- Water Bath Canners: Ideal for high-acid foods like tomatoes, water bath canners are simple to use and perfect for beginners. They efficiently seal jars and preserve the acidic contents safely.
- Pressure Canners: Pressure canning is essential for those looking to expand beyond tomatoes. They are capable of reaching higher temperatures needed for low-acid foods, offering more versatility in home canning.
- Specialized Canning Utensils: Tools like jar lifters, funnels, and bubble freers enhance safety and efficiency. A jar lifter ensures secure handling of hot jars, while a canning funnel aids in mess-free filling. A bubble freer is crucial for removing air bubbles, which can affect home food preservation.
- Digital Canning Systems: For the tech-savvy, digital canning systems provide precise temperature control and timings, streamlining the canning process with modern technology.
Top Reasons Canned Tomatoes Spoil
1. Tomatoes Floating in the Jars
One frequent issue encountered during the tomato canning process is tomatoes floating in the jars. This occurs due to air trapped within the tomato pieces or between them.
Minimizing Tomatoes Floating:
- Packing Tomatoes Tightly: To reduce floating, pack the tomatoes tightly in the jar, being careful not to crush them. This technique minimizes the air spaces between the tomato pieces.
- Removing Air Bubbles: After filling the jars with tomatoes or tomato juice, use a non-metallic spatula to run around the inside of the jar. This action helps release any trapped air bubbles, a common tomato canning problem that can affect the quality of the canned product.
Incorporating these practices in your canning process helps in preserving the visual appeal and quality of your home canned tomatoes.
2. Jars Not Sealing Properly
Achieving a proper seal is essential in the canning process, especially for preserving tomato products. An improper seal can lead to spoilage and food safety concerns.
A proper seal is crucial for safe preservation. The jar hasn't sealed properly if the lid doesn't "pop" and the center doesn't depress.
Troubleshooting Sealing Issues:
- Residue on the Rim: Before sealing, ensure the rims of your jars are clean. Residues from tomatoes or tomato juice can prevent the lids from sealing correctly.
- Inspecting Lids for Faults: Check each lid for any signs of damage. Faulty lids can compromise the integrity of the seal, which is crucial for preserving the acidity and safety of tomato products.
- Correct Headspace: Maintaining the correct amount of headspace in each jar is vital. Too much or too little space can affect the jar's ability to seal properly. Follow the specific canning recipe's guidelines for headspace, whether you're canning whole tomatoes, tomato juice, or other tomato products.
3. Why Canned Tomatoes Get Discolored
Discoloration in canned tomatoes is a common issue that can arise from several factors.
Causes and Solutions for Tomato Discoloration:
- Over-Processing: Adhere to the recommended processing times for your tomato canning recipes. Overcooking can cause the tomatoes to darken. Each canning recipe, whether for tomato sauce or whole tomatoes, has a specific process time that needs to be followed precisely.
- Managing Headspace: Too much headspace in the jar can lead to oxidation, causing the tomatoes to turn dark. Ensure you're leaving the correct amount of headspace as per the guidelines of the recipe you are using.
- Storage Conditions: Store your canned tomatoes in a cool, dark place. Exposure to light and heat can cause the tomatoes to discolor over time. Proper storage is essential in preserving the quality of your home canned tomatoes.
4. Stop Mold Growth In Canned Tomatoes
Mold growth in canned tomatoes is a serious concern as it indicates spoilage and can pose health risks.
Preventing Mold in Canned Tomatoes:
- Proper Sterilization: Sterilizing jars and lids before use is crucial. This step eliminates harmful microorganisms that could lead to mold growth. Use a boiling water bath or a dishwasher with a sterilization setting to sterilize your canning equipment effectively.
- Correct Processing Time: Follow the processing times recommended for your specific canning recipes. Whether canning tomato juice, tomato sauce, or whole tomatoes, the correct processing time is essential to kill any potential mold-causing bacteria.
- Ensuring a Proper Seal: A secure seal on your jars prevents air and bacteria from entering. After processing, check that the lids have been sealed by looking for a downward indentation in the lid. Any jars that haven't been sealed properly should be refrigerated and used quickly or reprocessed.
5. Tomatoes Soft or Mushy - Fix
Soft or mushy tomatoes can be disappointing. This can happen if the tomatoes are overripe or over-processed.
Preventing Soft or Mushy Tomatoes:
- Use Firm, Ripe Tomatoes: Choosing the right tomatoes is crucial. For canning, select firm, ripe tomatoes as they are less likely to become mushy. Avoid using overripe tomatoes, as they are more prone to losing their texture during the canning process.
- Avoid Over-processing: Adhere to the recommended process time for each tomato canning recipe. Over-processing the tomatoes by leaving them in the water bath or pressure canner for too long can result in a mushy texture.
- Handling Tomatoes Gently: When preparing and packing tomatoes into jars, handle them as gently as possible. Rough handling can cause the tomatoes to break down and become soft.
Remember, when it comes to canning, safety is paramount. If you're ever unsure about how to can tomatoes, it's best to err on the side of caution and discard it.
Safety Checks and Storage
Checking Seals: After the jars have cooled, check the seals by pressing down on the center of the lid. If it pops back, it’s not sealed properly and should not be stored.
Proper Storage: Store your canned tomatoes in a cool, dark place. Exposure to light and heat can degrade the quality over time.
Regularly Inspecting Your Canned Goods: Periodically check your canned goods for any signs of spoilage. It's better to err on the side of caution and discard any jars that show even minor signs of potential spoilage.
Clean jar rims, undamaged lids, and correct headspace are crucial for a proper seal. Always inspect your lids for damage and follow the recommended headspace guidelines.
Discoloration can result from over-processing, excessive headspace, or improper storage conditions. Following processing guidelines, ensuring correct headspace, and storing jars in a cool, dark place can prevent this.
Properly canned and stored tomatoes can last up to a year. Beyond that, they may start to lose flavor and nutritional value.