Sundried tomatoes, those intensely flavored jewels of the summer garden, are a culinary treasure. Preserving them allows you to enjoy their rich taste year-round. While sun drying is the traditional method, preserving them in oil and water bath canning offers a convenient and shelf-stable alternative. But the crucial question remains: How long do you water bath sundried tomatoes to ensure safety and quality?
Understanding the Importance of Safe Canning
Canning, while a rewarding process, requires meticulous attention to detail. The primary concern is eliminating the risk of botulism, a severe and potentially fatal form of food poisoning caused by the bacterium Clostridium botulinum. This bacterium thrives in low-oxygen, low-acid environments – conditions that can occur within improperly canned foods.
Sundried tomatoes, unlike some fruits, are not naturally high in acid. Therefore, they require acidification or pressure canning to safely preserve them. Water bath canning is suitable when tomatoes are adequately acidified with lemon juice or citric acid. Acidification is essential to prevent botulism.
The Role of Acidification in Water Bath Canning Sundried Tomatoes
Acidification lowers the pH of the tomatoes to a level where Clostridium botulinum cannot grow. This is a critical step before water bath canning.
Acceptable Acidifying Agents
Two primary acidifying agents are commonly used:
- Bottled Lemon Juice: Use commercially bottled lemon juice, as its acidity level is consistent. Fresh lemon juice can vary in acidity and is not recommended for safe canning.
- Citric Acid: A powdered acid available in most grocery stores and canning supply outlets.
Acidification Procedures
The amount of lemon juice or citric acid needed depends on the size of the jar and the type of tomato. Generally, for water bath canning sundried tomatoes in oil:
- Half-Pint Jars: Add 1 tablespoon of bottled lemon juice or ¼ teaspoon of citric acid per jar.
- Pint Jars: Add 2 tablespoons of bottled lemon juice or ½ teaspoon of citric acid per jar.
Always add the acidifying agent directly to the jar before adding the tomatoes and oil. This ensures even distribution.
Preparing Sundried Tomatoes for Canning
Proper preparation is key to a successful and safe canning process. This includes selecting high-quality tomatoes, rehydrating them, and packing them correctly.
Selecting and Preparing Tomatoes
- Choose Ripe, Firm Tomatoes: Avoid tomatoes that are bruised, damaged, or overripe.
- Sun Drying or Oven Drying: You can either sun dry your tomatoes or use an oven or dehydrator for faster results. Ensure the tomatoes are properly dried but still pliable.
- Rehydration: Rehydrate the sundried tomatoes before packing them into jars. This can be done by soaking them in hot water or olive oil for about 30 minutes. Rehydrating ensures even heat penetration during the canning process.
Packing Tomatoes in Jars
- Sterilize Jars and Lids: Sterilize your jars and lids by boiling them in water for 10 minutes. Keep them hot until ready to use.
- Add Acidifying Agent: Add the appropriate amount of bottled lemon juice or citric acid to each jar.
- Pack Tomatoes Tightly: Pack the rehydrated sundried tomatoes tightly into the jars, leaving ½-inch headspace.
- Add Oil and Herbs (Optional): Cover the tomatoes with olive oil, ensuring all air bubbles are released. You can also add herbs like garlic, basil, or oregano for added flavor. Be cautious about adding too many low-acid ingredients like garlic, as they can impact the safety of the product, even with acidification.
- Remove Air Bubbles: Use a non-metallic spatula or bubble remover to release any trapped air bubbles. Adjust headspace if necessary.
- Wipe Jar Rims: Wipe the jar rims with a clean, damp cloth to ensure a good seal.
- Place Lids and Rings: Center the lids on the jars and screw on the rings finger-tight.
Water Bath Canning Times for Sundried Tomatoes
The processing time depends on your altitude. Altitude affects the boiling point of water, requiring longer processing times at higher altitudes.
Processing Times Based on Altitude
Use the following chart to determine the correct processing time for your elevation:
| Altitude (Feet) | Half-Pint Jars (Minutes) | Pint Jars (Minutes) |
|——————-|—————————-|————————–|
| 0 – 1,000 | 35 | 40 |
| 1,001 – 3,000 | 40 | 45 |
| 3,001 – 6,000 | 45 | 50 |
| Above 6,000 | 50 | 55 |
These times are based on tomatoes that have been properly acidified.
Step-by-Step Water Bath Canning Instructions
- Fill the Canner: Fill your water bath canner with enough water to cover the jars by at least 1 inch.
- Preheat the Water: Bring the water to a boil.
- Load the Jars: Carefully lower the filled jars into the boiling water using a jar lifter. Ensure the jars are not touching each other.
- Process the Jars: Once the water returns to a rolling boil, start timing. Process the jars for the appropriate time based on your altitude and jar size, as indicated in the table above.
- Turn off Heat and Wait: After processing, turn off the heat and let the jars sit in the hot water for 5 minutes before removing them. This helps prevent siphoning.
- Remove Jars and Cool: Carefully remove the jars from the canner using a jar lifter and place them on a towel-lined surface, leaving at least 1 inch of space between them.
- Check Seals: Let the jars cool completely (12-24 hours). After cooling, check the seals by pressing down on the center of the lid. If the lid flexes, it is not properly sealed, and the jar needs to be reprocessed with a new lid or refrigerated.
- Store Properly: Remove the rings and store the sealed jars in a cool, dark, and dry place. Properly canned sundried tomatoes can last for up to a year.
Potential Problems and Troubleshooting
Even with careful preparation, problems can arise during the canning process. Knowing how to identify and address these issues is crucial for ensuring safety and quality.
Common Canning Problems
- Siphoning: This occurs when liquid escapes from the jars during processing. It can be caused by overfilling the jars, not removing air bubbles properly, or fluctuations in temperature.
- Jar Breakage: Jar breakage can occur due to thermal shock (sudden temperature changes), using damaged jars, or over-tightening the rings.
- Seal Failure: Seal failure can result from improper headspace, food particles on the jar rim, damaged lids, or inadequate processing time.
- Cloudy Liquid: Cloudy liquid can be caused by starch sediment from the tomatoes or minerals in the water. While it doesn’t necessarily indicate spoilage, it can affect the appearance of the final product.
Troubleshooting Tips
- Prevent Siphoning: Ensure proper headspace, remove air bubbles thoroughly, and avoid sudden temperature changes.
- Prevent Jar Breakage: Use good-quality jars, avoid thermal shock, and tighten the rings finger-tight only.
- Address Seal Failure: Check jar rims for cleanliness, use new lids, and ensure adequate processing time.
- Minimize Cloudy Liquid: Use filtered water and remove excess starch from tomatoes before canning.
Beyond Basic Canning: Flavor Enhancements
While safety is paramount, you can also experiment with flavors to create unique and delicious sundried tomato preserves.
Adding Herbs and Spices
Consider adding fresh or dried herbs like basil, oregano, thyme, or rosemary. Garlic cloves add a pungent flavor, while red pepper flakes provide a touch of heat. Be mindful of the quantity of low-acid ingredients like garlic to maintain safety.
Infusing the Oil
Infuse the olive oil with herbs and spices before adding it to the jars. This will create a more nuanced and flavorful product.
Considerations for Herbs and Garlic
While these additions are safe in small quantities, it is vital to research safe canning practices for herbs and garlic in oil. Some sources suggest blanching garlic before adding it to the jars. Always prioritize safety when introducing new ingredients.
Conclusion: Enjoying the Fruits (and Vegetables) of Your Labor
Preserving sundried tomatoes through water bath canning is a fantastic way to savor the flavors of summer throughout the year. By understanding the importance of acidification, proper preparation, and accurate processing times, you can confidently create safe and delicious preserves. Remember to always follow reputable canning guidelines and prioritize safety above all else. With a little practice and attention to detail, you’ll be enjoying your homemade sundried tomatoes for months to come. The key takeaways are that acidification is critical, processing times vary by altitude, and careful preparation is essential for a successful and safe canning experience.
Why is water bath canning necessary for sundried tomatoes preserved in oil?
Water bath canning is crucial for ensuring the safety of sundried tomatoes preserved in oil due to the risk of botulism. Botulism, caused by the bacterium Clostridium botulinum, thrives in low-oxygen, low-acid environments, which is precisely the kind of environment created when sundried tomatoes are submerged in oil. This bacterium produces a deadly toxin, and without proper processing, consumption can lead to severe illness or even death.
Water bath canning raises the temperature of the jars to 212°F (100°C), which is sufficient to kill or inactivate most harmful microorganisms, including Clostridium botulinum. While oil itself doesn’t inherently facilitate botulism, the lack of air and the low acidity of the tomatoes create a dangerous setting that requires the heat processing provided by water bath canning to ensure safety.
Can I skip water bath canning if I’m only preserving a small batch of sundried tomatoes in oil?
Even when preparing a small batch, skipping the water bath canning process for sundried tomatoes in oil is not recommended and poses a significant health risk. The potential for botulism growth is present regardless of the quantity of tomatoes being preserved. Small batches can be just as susceptible to contamination as larger ones.
The only way to guarantee the destruction of Clostridium botulinum spores in this type of preservation is through proper heat processing. Refrigerating the tomatoes after preparation will slow down bacterial growth, but it will not eliminate the risk of botulism. Therefore, for the sake of food safety, water bath canning remains an indispensable step.
How long should I water bath can sundried tomatoes preserved in oil?
The precise water bath canning time for sundried tomatoes preserved in oil depends on factors like jar size and altitude. Generally, pint jars (16 ounces) require approximately 35 minutes of processing time at altitudes of 1,000 feet or less. At higher altitudes, the processing time must be increased to compensate for the lower boiling point of water.
For altitudes between 1,001 and 3,000 feet, increase the processing time to 40 minutes. For 3,001 to 6,000 feet, process for 45 minutes, and for altitudes above 6,000 feet, process for 50 minutes. These processing times are critical for ensuring that the center of the jar reaches a temperature sufficient to eliminate potential botulism risks.
What specific type of oil is safest for preserving sundried tomatoes?
While various oils can be used, extra virgin olive oil is generally recommended for preserving sundried tomatoes due to its flavor profile and lower water content compared to some other oils. The lower water content helps minimize the potential for microbial growth. However, regardless of the oil type, proper acidification and heat processing are crucial for safety.
It’s important to choose a high-quality oil that is fresh and free from contaminants. Some cooks prefer using a blend of olive oil and another oil, such as canola or grapeseed oil, for a milder flavor. Ultimately, the choice of oil is a matter of personal preference, but the focus should always remain on following safe canning practices.
What if my jars don’t seal after water bath canning?
If a jar fails to seal after water bath canning, it’s essential to address the issue immediately for food safety reasons. A proper seal prevents spoilage by creating an airtight barrier against microorganisms. Several factors can contribute to a failed seal, including improper filling, debris on the jar rim, or a faulty lid.
If the jar fails to seal within 24 hours, you have two options: reprocess the jar with a new lid, ensuring proper headspace and a clean rim, or refrigerate the contents immediately and use them within a week. It is not safe to store unsealed jars at room temperature. Reprocessing must be done within the same 24-hour timeframe.
How do I properly acidify sundried tomatoes before canning?
Acidifying sundried tomatoes is a crucial step in ensuring the safety of the canning process. Tomatoes are naturally low-acid foods, and adding an acidulant, such as lemon juice or vinegar, helps to lower the pH to a level that inhibits the growth of Clostridium botulinum. The USDA recommends adding either bottled lemon juice or vinegar to each jar before filling with the tomatoes and oil.
For safety, add 1 tablespoon of bottled lemon juice or 1 tablespoon of 5% acidity vinegar per pint jar. This step is non-negotiable, as it provides an additional layer of protection against botulism. Always use bottled lemon juice or vinegar to ensure a consistent acidity level, as the acidity of fresh lemons and homemade vinegar can vary.
Besides water bath canning, are there other safe methods to preserve sundried tomatoes in oil?
While water bath canning is a common and effective method, pressure canning is generally not recommended for sundried tomatoes in oil. The high oil content can interfere with proper heat penetration during pressure canning, potentially leading to uneven heating and unsafe results. The best alternative is freezing the sundried tomatoes after they have been packed in oil.
Freezing effectively halts microbial growth and is a safe method for long-term storage. However, freezing can affect the texture of the tomatoes, making them softer when thawed. Be sure to package the tomatoes properly in freezer-safe containers or bags to prevent freezer burn. Thaw the desired amount in the refrigerator and consume within a few days.