Passata is a medium-thick, pourable, uncooked red tomato sauce made from crushed and strained tomatoes. It has almost the same consistency as tomato ketchup.
The thickness of the sauce is owing to the high-quality paste-type tomatoes that are used (as opposed to watery, slicing-type tomatoes.)
To make passata, tomatoes are passed (thus the name) through sieves to crush the tomatoes and remove the skin, seeds, and cores at the same time.
A thick, fresh tomato sauce results to use in recipes.
You can make it at home with a food mill or sieve, or buy it commercially canned in bottles, tins, or tetrapak cartons.
Note that commercial passata isn’t cooked either beyond what sterilization heating it necessarily receives in the canning process. This isn’t a ready to go pasta sauce. You have to treat the contents as fresh, sauced, strained tomatoes ready to use in your recipe and be cooked.
Ingredient listings will vary. Besides tomato, you may see salt, and or salt and citric acid added. Occasionally, a container will have a basil leaf added for flavour, in which case you may see on the label in Italian “al basilico.”
Italians themselves rarely make pasta sauce totally from scratch anymore. They usually start with a bottle of passata.
You can use it in making a pasta sauce, as a base for a condiment recipe such as ketchup, or as a spread on pizza.
If using in recipes for home canning — pasta sauces, etc — full USDA safety precautions for home-canned tomato products must still be followed: acidification and / or pressure-canning depending on the tomato product being made, even if the bottle says it already contains citric acid.
If a recipe is calling for a small amount — let’s say 1 or 2 tablespoons of passata, instead of opening a whole jar just for that you can use tomato paste instead (either from a small tin or from a tube.)
If it’s a larger amount called for, you can just use tinned tomatoes, whizzed through a blender or food processor then strained.
But never substitute large amounts of tomato paste for large amounts of passata, as the tomato paste will be too rich and sweet.
A 700 ml (24 oz) bottle of passata would be equivalent to passing 1.5 kg (3 lbs) of quality paste-type tomato (such as Roma, San Marzano) etc, through a food mill.
In Italian, the full name is “passata di pomodoro”, with passata referring to being passed through a sieve, and pomodoro meaning tomato.