When prepping, the first step most people is to buy canned food for storage. Nothing wrong with starting here, I did myself. There is one commercially canned vegetable that does not store well on the shelf in prepping supplies. Tomatoes have too much acid to last well in a can, and they end up spoiling. The can then domes up:
You can see doming here on this can. All types of commercially canned tomatoes seem to have this problem. So if you decide to prep with 'off the shelf' spaghetti sauce, be sure and buy it in a glass jar!
The way not to prep:
These cans are not for prepping, so don't worry, they were for the homeless meal! But Do Not put this on the shelf...when you need it, it will be spoiled.
Fortunately, tomatoes are easy to preserve at home:
My preferred method is to dehydrate sliced tomatoes (this includes sun dried), put them into a canning jar, and pull a hard vacuum on them. This method allows them to be stored for decades with little loss in nutrition. They are moisture independent, and temperature extremes do not affect them. I still store them in the dark, just to keep them as fresh as possible. I find that 8 pounds of cherry tomatoes will fit in a one quart jar, so it's space frugal too. As a side note, once dehydrated, mylar bags and oxygen absorbers (if you have the equipment); will preserve the tomatoes as well as the jars, except for mice problems. I will address pest problems in another post, but vermin problems should always be in the back of your mind!
Another good way to preserve tomatoes is by pressure canning (or open kettle if you're good). It must be stored in temperate conditions in the dark, but I know of some that were stored this way for 40 years, that were still editable! Light will rob vitamins, and they can freeze; but this is the least expensive way to preserve tomatoes long term, as it's the simplest equipment.
The last good way to store tomatoes is by freeze drying. This equipment is expensive, but retains most of the nutrients intact. The product can be stored like the dehydrated tomatoes are stored, and is long term stable. I haven't seen a good comparison of nutrition, between the dehydrated and the freeze dried tomatoes; but I suspect they are similar!
I have deliberately omitted the freezing option, because the grid can't be counted on when really prepping! Anything in a freezer must be eaten, or lost in short order. As a result, freezing is not a viable prepping storage method in my humble opinion!
Do you have another preferred method of preservation? Please add it in the comments.