Using Surplus Tomatoes: How to Make and Can Tomato Sauce in Three Steps
Use up surplus tomatoes from your garden and save money at the grocery store next winter by making and canning your own tomato sauce. It's a multi-step process, but the project is not that daunting when spread out over the course of two or three days. And it will be worth the effort next winter. There's nothing like a jar of homemade tomato sauce to whip up a quick and healthy pasta dinner or a pot of chili on a cold night.
Here's how to make and can your own tomato sauce in three simple steps:
Step 1: Juice the Tomatoes
You will need roughly 1-3/4 pounds of tomatoes for every pint jar of sauce produced. Because it's just as easy to make eight jars as it is one, I recommend starting with roughly 14 pounds of fresh, vine-ripened tomatoes. Paste tomatoes (my favorites are San Marzano and Amish Paste) make the best sauce, but any variety will work. For best results, use fully ripe fruit with no soft spots. Wash the tomatoes, remove the stems, and trim off any blemishes.
You have a few options for juicing the tomatoes. The old-fashioned way is a laborious process, which requires peeling and coring the tomatoes, heating them and then forcing them through a sieve to remove the seeds. Avoid the effort by investing one of the following handy kitchen gadgets:
- The Victorio food strainer: Quarter the tomatoes and feed them into the hopper of this device, which clamps to the countertop. Turn the crank (bonus, this is a great upper arm workout!), and let the tomato juice flow.
- KitchenAid stand mixer with food grinder and strainer attachments: This is more expensive option, but if you're already a proud owner of a KitchenAid stand mixer, invest in the attachments. The attachments work much the same way as the Victorio, but the electric motor of the mixer does all the hard work.
You will get about 4-1/2 quarts of juice, depending on ripeness and variety of tomato used.
If not proceeding immediately to Step 2, refrigerate the juice in a non-reactive container (e.g., glass) for up to two days.
A word about nutrition:
Vegetables begin to lose nutritional value upon harvest. Cook and preserve fresh tomatoes within a few days of harvest to optimize valuable nutrients, but remember that vitamins are lost during processing and further decline during storage.
Step 2: Make the Sauce
This recipe makes a versatile sauce that, after canning, can be cooked down to make pizza sauce, or spiced up for use in Italian or Mexican recipes.
Simple Tomato Sauce
1 T extra virgin olive oil
1 large onion, chopped (about 2 cups)
3 cloves garlic, minced
4-1/2 quarts tomato juice
2 tsp salt
Heat olive oil in a large, non-reactive stock pot (i.e., stainless steel, not aluminum). Add onion and cook over medium-low heat, stirring occasionally, about 10 minutes or until translucent. Add the garlic and stir for one minute. Carefully pour in the tomato juice and add the salt. Cover the stock pot and turn the heat up to medium-high. When the sauce reaches a boil, uncover and reduce the heat to low. Simmer, uncovered, for two hours to allow the sauce to thicken, stirring occasionally.
If not proceeding immediately to Step 3, remove the sauce from heat and cover. When the pot has cooled enough to handle, fill sink halfway with ice water. Set the covered pot in the sink to cool to room temperature. Refrigerate the covered pot for up to 24 hours. When ready to process, return the sauce to boiling then turn down heat and keep sauce hot.
Step 3: Process the Sauce
The sauce is processed using the boiling-water canning method. Boiling-water canning (also called water bath canning) is one of two methods for safely home-canning food to prevent bacteria growth. The other is the pressure canning method.
Boiling-water canning is safely used for high-acid foods like tomatoes, pickles and fruit. Because of a risk of botulism if low-acid foods are not processed at high enough heat, the pressure canning method must be used to process any foods that have a pH value of greater than 4.6. Most tomatoes have a pH value of less than 4.6 and adding lemon juice or citric acid ensures all tomatoes may be processed safely in a boiling-water canner.
The boiling-water canning method does not require the specialized (and somewhat scary) equipment of the pressure canning method. If you don't have an actual boiling water canner, typically made of porcelain-covered steel with a removable jar rack, you can make do with just about any large pot. Make sure 8 pint jars will fit in a single layer in the pot without touching and that the pot is deep enough to allow at least one inch of water to cover the jars during processing.
You will need 8 glass pint jars and 8 two-piece caps consisting of a flat metal lid with a built-in gasket and a metal screw band. Processing the jars and caps will create a vacuum seal that prevents bacteria from entering and preserves the jars' contents for later use. Use Mason-type jars made specifically for canning (Ball and Kerr are common brands). Either regular or wide-mouth jars may be used, just make sure the two-piece caps are of the corresponding size. The metal lids should be unused, less than 5 years old and free from defects.
Other Tools I Recommend:
- Jar lifter: If your canner is not equipped with its own removable jar rack with lifting handles, this plastic-coated tools is made specifically for lifting canning jars in and out of the canner.
- Lid wand: A magnetic tool used to transfer the lids from the hot water sterilization bath to the jars without touching them.
- Wide mouth funnel: Use this tool to avoid messes when filling the jars with sauce.
- Ladle: To fill the jars.
- Tongs: Useful for pulling things out of the hot water sterilization bath.
- Spatula: Use a thin plastic spatula to release any air bubbles in the jars. Do not use metal.
After assembling the equipment, fill the canner halfway with water and preheat to at least 180°F, but not to boiling. This hot water will be used to sterilize the jars and lids before using them. Sterilization is a key step in the process because it prevents the introduction of unwanted bacteria into the food. Have additional water heating in a tea kettle if needed.
Wash the empty jars in the dishwasher, or wash in hot, soapy water and rinse thoroughly. Submerge the clean jars in the hot water in the canner for at least 10 minutes, or until you are ready to fill them.
Wash the lids and screw bands in hot, soapy water and rinse thoroughly. Dry the bands and keep them clean and in a location that's easy to reach from where you'll be filling the jars. The lids should be submerged in hot, but not boiling, water until ready to use them. You may want to use a separate saucepan of hot water for this purpose, because it gets a bit tricky trying to fish the lids out of the big canner, or you can invest in a "lid rack" that has a long handle for lifting the lids out of the canner. A small plastic colander with a handle works well as a makeshift lid rack. Simply place the cleaned lids in the colander and submerge the colander in the hot water in the canner. Also sterilize any other tools you will be using, such as the ladle, funnel or spatula.
After the jars have been sterilized, add 1 tablespoon bottled lemon juice (do not use fresh-squeezed lemon juice) or 1/4 teaspoon powdered citric acid to each jar and fill with hot tomato sauce, leaving a 1/2-inch headspace. Release any air bubbles by running a plastic spatula along the inside of the jar. Wipe the jar rims with a clean damp cloth or paper towel to remove any food particles that may cause seal failures. Place the lid, gasket side down, on the jar rim and fit the metal screw band over the lid and tighten by hand. While the rings must be tight enough to prevent food from escaping as the jars are processed, do not over tighten as that may cause the lids to buckle or jars to break during processing.
Load the filled jars into the canner one at a time, using either a canning rack or jar lifter. If necessary, add more hot water so that there is at least one inch of water above the tops of the jars. Turn the heat up until the water begins boiling. Set a kitchen timer for 35 minutes to start the processing time. Cover the canner with the lid and lower the heat just enough to maintain a gentle boil for the entire 35 minutes.
After boiling the jars for the entire 35 minute processing time, turn off the heat and remove the lid of the canner. Carefully remove the hot jars from the canner using a jar lifter and place them on a wooden cutting board covered with a kitchen towel. Leave at least an inch between the cooling jars. The jars are very hot. Do not attempt to retighten the bands or check the seals.
During the cooling time, which may take 12 hours or more, you may hear popping noises as the jars seal. The noise is the result of the vacuum created when the cooling sauce contracts, fusing the lid to the jar. After the jars have cooled completely, you can test the seal by applying pressure to the center of the lid. If the lid doesn't move, it is sealed. If it depresses and makes a popping sound, the seal has failed. In that case, the jar should be refrigerated and the contents used within two weeks.
Remove the screw bands from the sealed jars and wipe the jars with a clean damp cloth to remove any hard water residue. Label the lid with the contents and date processed and store in a cool, dark, dry place.
Sealed jars will not spoil if stored between 50° and 70°F. Quality does decline over time, however. Use canned tomato sauce within a year of processing for best results.
Bonus Step: Enjoy Your Efforts Next Winter
Even though your garden may be covered in snow, spring doesn't seem so far away when you’re eating something you grew just a few feet outside your back door. Here's a quick recipe for a cold winter night:
Pasta with Easy Bolognese Sauce
While boiling water and cooking pasta, heat olive oil in a deep-sided skillet. Sauté onion and carrot over medium low heat until onion is translucent and carrot has softened, about 10 minutes. Add ground beef and cook until beef is browned. Drain off any excess fat. Add tomato sauce, salt, pepper and oregano. Heat to just boiling and turn heat to low and simmer for 10 minutes. Turn off heat and stir in cream. Serve over spaghetti and top with grated Parmesan cheese. Serve with a green salad.
2 servings whole wheat spaghetti, cooked as directed on box
1 tsp extra virgin olive oil
1/2 cup chopped onion
1 large carrot, peeled and finely chopped
1/2 pound lean ground beef
1 pint tomato sauce
1/2 tsp salt
Fresh ground pepper to taste
1/2 tsp dried oregano
2 T cream
Freshly grated parmesan cheese