It needs to be cooked ahead of time so that the flavors are blended and you can taste it and make sure it’s how you want before canning. With the big pot for canning, I have a quilted hot pad under them instead of a rack. I never bought a rack because the hot pads work just fine. You need something under the jars but it can be as simple as a kitchen towel (I have not broken a jar in 3 years! So it must be okay, lol). I have some posts on the water bath method that explain my equipment in more detail.
We have adapted our salsa method from Well Preserved. What is special about their method is the straining of the tomatoes before packing them. This straining and sweating of the tomatoes is the same concept for pulling the moisture out of zucchini before cooking. By pulling the moisture out of the tomatoes, you allow the fruit to keep a more crisp texture when canned.
Absolutely love this. You were right. Getting as much water out is so really important step. I drained as best I could with colanders then put in glass bowl. More liquid settled so I used a turkey baster to remove more liquid. Won’t ever make it another way. I have been looking for a salsa that has body and flavor and this is outstanding. I made my own tomato sauce as the tomatoes I got from local farmer were meaty and very flavorful. Thank you for posting this outstanding salsa recipe.