If you were hot-packing tomatoes the headspace shouldn't have changed that much during processing unless liquid was siphoned from the jars. With water bath that can happen with over-packing, among other causes.

All that air reduced the shelf life. Otherwise the flavor of the tomatoes should have remained essentially the same.

Carol

Agree with Carol that something you did last year caused loss of lots of liquid from the jars. That isn't supposed to happen but that is why the taste now.

Can you tell us exactly which set of instructions you used of the many methods available? Or at least what was the source of the instructions? That would help us figure out what might have gone wrong.

As to the pasta sauce, you'll need to define the ingredients you want it to include or what recipe you want to use. The label "pasta sauce" means very different things to many people. For some it means just plain tomato sauce, for others it is tomato sauce with meat, and to others it is tomato sauce with lots of other vegetables mixed in it and they are all canned very differently and may require pressure canning.

Dave

Canned tomatoes will taste a little different than the frozen ones and really different than fresh. You can get close, but I haven't found that 'fresh off the vine' taste. still better than the commercially canned taste.

They had too much air space left in the jars. That could potentially do that, or they could even spoil.
The best method I think, and the one we recommend using is the crushed tomato method from the Univ. of Georgia.
The tomatoes are cooked before going into the jars so that eliminates the tomatoes from shrinking down any more during processing.