How to Can Tomato Sauce from Fresh Tomatoes: A Comprehensive Guide
Canning tomato sauce from fresh tomatoes involves a straightforward process of preparing, cooking, and preserving the sauce in sterilized jars, ensuring shelf-stable goodness for months to come. This guide walks you through each step, from selecting the best tomatoes to sealing the jars properly, allowing you to enjoy homemade tomato sauce year-round.
Why Can Tomato Sauce? A Taste of Summer, All Year Long
The allure of homemade tomato sauce is undeniable. The vibrant flavor of sun-ripened tomatoes, cooked down and transformed into a rich, savory sauce, far surpasses anything you can find in a jar at the grocery store. Canning allows you to capture that essence of summer and enjoy it throughout the year.
But beyond the taste, canning your own tomato sauce offers several other benefits:
- Control over Ingredients: You know exactly what’s going into your sauce, avoiding artificial flavors, preservatives, and excessive sodium.
- Cost-Effectiveness: When tomatoes are in season and plentiful, canning allows you to stock up at a fraction of the cost of store-bought sauce.
- Reduced Waste: Canning preserves excess tomatoes that might otherwise go to waste.
- Personalization: You can customize your sauce with your favorite herbs, spices, and vegetables.
Gathering Your Supplies: The Canning Arsenal
Before you embark on your canning adventure, ensure you have all the necessary equipment:
- Fresh Tomatoes: Choose ripe, firm tomatoes that are free from blemishes. Roma or plum tomatoes are ideal due to their meatier texture and lower water content.
- Canning Jars and Lids: Use specifically designed canning jars with two-piece lids (flat lid with a separate screw band). Ensure the lids are new and the jars are free from chips or cracks.
- Canning Pot with Rack: A large, deep pot with a rack is essential for safely processing the jars in boiling water.
- Jar Lifter: This specialized tool is crucial for safely lifting hot jars in and out of the canning pot.
- Lid Lifter: A magnetic lid lifter allows you to retrieve sterilized lids from hot water without contamination.
- Wide-Mouth Funnel: Makes filling jars easier and cleaner.
- Clean Kitchen Towels: For wiping jars and surfaces.
- Measuring Cups and Spoons: For accurate ingredient measurements.
- Citric Acid or Bottled Lemon Juice: Essential for ensuring safe acidity levels in the sauce.
- Other Ingredients: Onions, garlic, herbs, spices, salt, pepper, and olive oil (optional).
The Canning Process: Step-by-Step Guide
Canning tomato sauce is a multi-step process that requires careful attention to detail. Here’s a breakdown of each stage:
Prepare the Tomatoes: Wash the tomatoes thoroughly. Remove the cores and any blemishes. There are a few popular methods for peeling tomatoes:
- Blanching: Score an “X” on the bottom of each tomato. Submerge them in boiling water for 30-60 seconds, then transfer them to an ice bath. The skins should slip off easily.
- Roasting: Roast the tomatoes at 400°F (200°C) until the skins blister and blacken. Let them cool slightly before peeling.
Prepare the Sauce: Roughly chop the peeled tomatoes. In a large pot, sauté diced onions and garlic in olive oil (optional) until softened. Add the chopped tomatoes, herbs, spices, salt, and pepper. Bring to a boil, then reduce heat and simmer for at least an hour, or until the sauce has thickened to your desired consistency. Stir frequently to prevent sticking.
Sterilize Jars and Lids: Wash jars and lids in hot, soapy water. Rinse thoroughly. Place the jars on the rack in the canning pot and cover with water. Bring to a boil and boil for 10 minutes. Remove the jars and set them aside to keep warm. Place the lids in a separate saucepan and simmer (do not boil) for 10 minutes.
Add Acid: Always add acid to your tomato sauce to ensure proper preservation. Add either citric acid (¼ teaspoon per pint jar, ½ teaspoon per quart jar) or bottled lemon juice (1 tablespoon per pint jar, 2 tablespoons per quart jar) to each sterilized jar.
Fill the Jars: Using a wide-mouth funnel, carefully ladle the hot tomato sauce into the sterilized jars, leaving ½ inch of headspace (the space between the sauce and the top of the jar).
Remove Air Bubbles: Gently tap the jars on the counter or use a non-metallic utensil to release any trapped air bubbles.
Wipe Jar Rims: Wipe the rims of the jars with a clean, damp cloth to remove any spills or residue.
Place Lids and Bands: Place a sterilized lid on each jar, and then screw on the band fingertip-tight (not too tight, not too loose).
Process the Jars: Carefully lower the filled jars onto the rack in the canning pot. Ensure the jars are completely covered with water (at least 1-2 inches above the top of the jars). Bring the water to a rolling boil. Process the jars for the following times, adjusting for altitude:
Jar Size Processing Time (0-1,000 ft) Processing Time (1,001-3,000 ft) Processing Time (3,001-6,000 ft) Processing Time (Above 6,000 ft) Pint 35 minutes 40 minutes 45 minutes 50 minutes Quart 40 minutes 45 minutes 50 minutes 55 minutes Cool and Check Seals: After processing, turn off the heat and carefully remove the jars from the canning pot using a jar lifter. Place them on a towel-lined surface, leaving space between each jar. Let the jars cool completely (12-24 hours). As the jars cool, you should hear a “popping” sound as the lids seal. After the jars have cooled, check the seals by pressing down on the center of each lid. If the lid doesn’t flex or pop up, it’s sealed properly.
Store: Remove the screw bands and label the jars with the date. Store the jars in a cool, dark, and dry place. Properly canned tomato sauce can last for up to 18 months.
Common Mistakes to Avoid: Ensuring Canning Success
- Insufficient Acidity: Failing to add enough acid (citric acid or lemon juice) can lead to spoilage and potentially dangerous botulism.
- Improper Headspace: Leaving too little or too much headspace can prevent a proper seal.
- Overfilling Jars: Overfilling can cause the contents to expand during processing, leading to leakage and seal failure.
- Under-Processing: Insufficient processing time can result in incomplete sterilization and spoilage.
- Reusing Lids: Always use new lids for each canning batch. Used lids may not seal properly.
- Not Adjusting for Altitude: Higher altitudes require longer processing times due to the lower boiling point of water.
Frequently Asked Questions (FAQs)
Can I use heirloom tomatoes for canning sauce?
Yes, you can use heirloom tomatoes. However, heirloom varieties can vary significantly in acidity. It’s crucial to use bottled lemon juice or citric acid to ensure a safe acidity level, regardless of the tomato type. Consider testing the pH of your sauce if you are uncertain.
What if a jar doesn’t seal?
If a jar doesn’t seal within 24 hours, it’s not shelf-stable and needs to be refrigerated. You have a few options: consume the sauce within a week, reprocess it with a new lid within 24 hours, or freeze it. Freezing is a great way to preserve smaller batches that didn’t seal properly.
Can I use olive oil in my tomato sauce?
Yes, you can use olive oil. However, it’s recommended to use it sparingly as oil can potentially interfere with the sealing process. Sautéing vegetables in a small amount of olive oil before adding the tomatoes is a common practice.
How do I adjust the processing time for higher altitudes?
Refer to the processing time chart in the guide. Higher altitudes require longer processing times because water boils at a lower temperature, which affects sterilization. Failure to adjust for altitude can lead to spoilage.
Can I use frozen tomatoes to make tomato sauce for canning?
Yes, you can. Thaw the frozen tomatoes completely before using them. Keep in mind that frozen tomatoes tend to be softer and may produce a more watery sauce. You may need to simmer the sauce for a longer time to achieve the desired consistency.
What herbs and spices are best for tomato sauce?
The choice of herbs and spices is a matter of personal preference. Common additions include basil, oregano, thyme, rosemary, garlic, onion, salt, pepper, and a pinch of red pepper flakes. Experiment to find your perfect blend!
How long does canned tomato sauce last?
Properly canned tomato sauce can last for up to 18 months when stored in a cool, dark, and dry place. Always check for signs of spoilage (bulging lids, unusual odors) before consuming.
Can I can tomato sauce with meat in it?
No, it is not recommended to can tomato sauce with meat using a water bath canner. Meat requires higher temperatures for safe processing, which can only be achieved with a pressure canner.
Why is it important to remove air bubbles from the jars?
Air bubbles can create pockets of uneven heating during processing, potentially leading to incomplete sterilization and spoilage. Removing air bubbles ensures that the heat penetrates evenly throughout the sauce.
What does “fingertip-tight” mean when tightening the jar bands?
“Fingertip-tight” means tightening the band until you feel resistance, then giving it a slight extra turn. The goal is to secure the lid without overtightening, allowing air to escape during processing. Overtightening can cause the jar to break.
How do I know if the tomato sauce has gone bad?
Look for signs of spoilage, such as a bulging lid, a broken seal, a foul odor, mold, or a cloudy appearance. If any of these signs are present, discard the sauce immediately. Don’t taste it!
Can I add other vegetables to my tomato sauce before canning?
Yes, you can add other vegetables like peppers, zucchini, or carrots. It’s important to properly prepare and cook all vegetables thoroughly before adding them to your tomato sauce. For thicker, chunkier sauces it’s recommended to follow tested canning recipes to ensure safe processing times.