“It has come to my attention that many people are unwittingly throwing away free tomato sauce when they preserve their summer tomatoes.
Here’s the thing: like all fruit, the skin of tomato is where much of the natural pectin resides. Pectin is the starch that gives jams their thickness and good tomato sauce its natural, noodle-coating thickness.
But tomato skins in a canned tomato product can be tough and stringy, and do that thing where they stick between your teeth and make you feel like you are getting a floss job from Satan’s dentist. This is why almost every canned tomato recipe calls for the initial step of coring, blanching and skinning tomatoes…”