Sorry I’ve been out of the loop; should’ve seen this post sooner. I’ve spent years processing tomatoes in almost every way possible, so here’s what I’ve noticed:
*Dried tomatoes have a limited shelf life, even if vacuum-sealed. Eventually, they darken and lose quality. If they appear red and taste good, they can be used for sauce. Unless they were blanched, peeled before processing, the skins will make any dish less appealing. Many tomatoes have seeds in quantities which can produce bitter off flavors if cooked for long hours, pressure cooked, or canned. For these reasons, I’d suggest a boiling water soak, until the tomatoes are soft enough to run through a food mill to separate out skins and seed. A Foley-type mill works well. Sieves would require a softer tomato-more water. Water can always be added later.
*“Fresh” sauce does not taste like fresh tomatoes, unless it’s raw tomatoes which have not been cooked. Even brief cooking makes the meaty, paste type tomatoes watery. My favorite sauces, from fresh tomatoes, are reduction sauces. Tomatoes are cored, cut into chunks and briefly simmered to destroy an enzyme which causes solids to separate, and to make straining easier. In season, I’m processing about 60 lbs/27 kilos every 4-5 days. To handle this volume, I use a Squeezo strainer to produce quantities of juice/puree. The Squeezo separates out seeds and skins by cranking the handle. Many similar products exist. Reduction, in volume, is carried out in a neverburn-type stock pot, set on gentle simmer for hours. These "never burn pots are perfect for the ask, since you don’t have to spend hours stirring, watching constantly; you need to pat attention more towards the end, when there’s little water left. The reduction is usually 11-12 parts reduces to 3, by volume. This is with Italian paste/plum varieties. Juice is canned in mason jars. Low acid tomatoes can grow botulism-add citric acid per guidelines. I grow old heirlooms, with plenty of acid.
*Freeze dried tomatoes rehydrate into a soggy mess, if you are thinking of using slices. While they may be useful in some dishes, you’ll still have the skins, which form unpleasant strands. So far, my favorite use for the freeze dried tomatoes is tomato powder. Add boiling water and you have juice or a type of sauce. This sauce may need additional cooking, depending on the flavor you want. Cold water added to freeze dried or dried tomatoes might lead to liquid/solid separation. To make tomato powder, crush the freeze dried tomatoes. I use a wooden potato “stomper”. This keeps seeds and skin mostly intact, while the soft parts crumble. Then, it’s easy to sieve out the seeds and skins. You’re left with a pink powder (if using red tomatoes). This gets vacuum sealed with oxygen absorbing packets, for long-term storage. Oxygen absorbing packets are non toxic, basically packaged iron which converts to rust, stealing oxygen from containers.
Tomato powder can be added to salad dressings or anywhere the flavor of tomatoes is wanted.
By far, tomato puree/juice (canned or via powder) is the best, most flexible product. You can make Bloody Marys, Gazpacho, reduce it to pasta sauce, reduce it further to paste.
I just tried something new to me. Since shelf space is filling and there’s a LOT of canned reduction sauce, I freeze dried the reduction, making it stable for years (if properly sealed). This should keep much, if not all of the original flavor. Unlike canned, which might keep a few years. Freeze dried can keep 15-20 years without degrading.
Disease has crept into the garden space. For years, I grafted heirlooms on resistant rootstocks, which worked great; tomatoes were super productive all season. Now, I need to grow something outside the nightshade family. Thus, the goal is to enjoy the past couple year’s supply of dried, freeze dried and canned in ways that little, if any goes bad.