Heat = tomato's worst enemy.
When you heat a tomato it begins to lose its fresh taste. Most canned tomato products are made from paste and water (paste = tomatos that have been cooked down).
The 6-in-1 tomatoes that we're all raving about are different in that they use a low-heat method to can their product. Here is a snippet from their website:
"The Escalon facility is designed with proprietary technology that minimizes the 'heat' applied to the tomatoes during processing. By minimizing heat and residence (cooking) time, Escalon is able to capture more fresh, tomato color and flavor than other processors who design their factories to maximize throughput."
Click this link to read more about their process:http://www.escalon.net/differences.asp
There are only two manufacturers that I am aware of that use similar processing techniques and therefore produce a superior tasting tomato product. Those two companies are Escalon (6-in-1) and Stanislaus.
As I've said before, I have tasted numerous canned tomato products side-by-side, raw, straight out of the can. The 6-in-1 tomatoes, by far, have the freshest tomato flavor.
When making a pizza sauce, you sould try not to pre-cook (or simmer) the sauce before applying it to the pizza. Remember, cooking removes the fresh taste. You should apply the sauce in a raw, uncooked, state and let it cook in the oven on the pizza. You might have to blend two types of tomato products together in order to have a thick, non-watery, raw sauce. I usually mix 6-in-1 tomatoes with Escalon's Bonta sauce (Bonta is similar to tomato paste, yet Escalon's processing technique retains much of the fresh flavor of the tomato.)