This super basic canned tomato sauce has just tomatoes and salt (and jarred lemon juice to assure a proper acidic environment for canning), making it perfect for canning because you can add any additional flavors later when you go to use it. Fleshier Roma, plum, or Early Girl tomatoes are great here since they have less juice to cook down to make the sauce.
Note: No, just to be clear, you can't just can your favorite tomato sauce. Safe canning requires that the food has a guaranteed acidity. Here, that is assured by the addition of bottled lemon juice.
- 8 pounds supremely ripe tomatoes (a bit overripe isn't bad here either)
- 1 teaspoon sea salt
- 4 Tablespoons jarred or bottled lemon juice
- 4 pint-size jars with sealable lids for canning
- Rinse the tomatoes clean and pat them dry. Now you need to remove the seeds and skin. This can be done one of three ways:
Option 1: Bring a pot of water to a boil. Cut a small "x" in the bottom of each tomato and blanch them in the boiling water for about 30 seconds, use a slotted spoon to transfer the tomatoes to an ice bath to cool, lift them out, slip off their skins (they really will just slip right off!), cut the tomatoes in half, and squeeze out their seeds.
Option 2: Roughly chop the tomatoes and run them through a food mill.
Option 3: Whirl the tomatoes quickly in a blender and push the puree through a fine sieve.
- Put the peeled and seeded tomatoes or tomato puree in a pot with the salt and bring just to a boil. Reduce the heat to maintain a steady but gentle simmer and cook, stirring now and again, until the mixture is reduced by about a third, about 45 minutes. If at any point the mixture starts sticking to the pot, lower the heat and stir more often.
- Meanwhile, bring a canning kettle full of water to a boil and sterilize the jars and lids (boil the jars for 10 minutes and transfer to a cooling rack to let dry.
- Put 1 tablespoon of the lemon juice in each of the 4 jars. Transfer the hot tomato sauce to the hot jars (if you have a wide-mouth canning funnel, this is the time to use it!), leaving about 1/2 inch of head space at the top. Screw on the lids, put the jars in a canning rack, and lower them into the boiling water in the canning kettle. Process (boil) for 40 minutes. There needs to be at least an inch of water covering the jars, so keep an eye on the water level, adding more boiling water, if needed.
- Remove the jars and let them cool. Store them in a cool, dark place (a cupboard or pantry works great) until you're ready to use some tomato sauce.