Homemade Tomato Purée Recipe and Canning Tips
To can: Bring a large canning kettle full of water to a boil. Sterilize the pint jars by boiling them for 10 minutes and allow to air dry. Soften the lids by simmering them for a few minutes. Put 1/4 teaspoon citric acid or 1 tablespoon bottled lemon juice in each pint jar.