Wash, core and take off any spots on tomatoes. Quarter them and place in large stock pot. Once your pot is about half full put it on the stove on low heat. Once the tomatoes start to give up their juice then you can turn the fire up to medium high.
Keep adding tomatoes to it until you are about 3/4's full. Bring it to a slow simmer and let cook until the tomatoes begin to fall apart. Remove from heat.
Working in small batches run the tomatoes through the blender. Pour through a strainer to separate the seeds and skin from the juice.
Pour juice into cleaned and sterilized jars. Fill jars 1/4 inch from top.
Once you have your seven jars ready for the canner, add them into the warm water of the canner. Bring to a boil and process for 30 minutes. Once the time is done, turn off the heat, remove the lid and leave the jars in the canner water. This will prevent the boiling over of the hot liquid. Once that five minutes are done remove the jars to cool. Make sure each jar top is "depressed". If you press in the center of the lid, it should not bounce back. It can take a little while to seal sometimes. I usually check the next morning. Any that do not seal should be refrigerated and used up.
Tips and Tricks
Once you get your pot about half full put it on the stove so the tomatoes can start breaking down. Stir frequently as they will easily stick at this point. Add as you cut. The tomatoes in the pot will take up less space as they lose their juice. Keep adding tomatoes, they will cook faster being surrounded by the hot liquid of the cooked tomatoes.
Cook tomatoes fully. It will be easier to break them down in the blender and then strain them if they are nice and soft.
Have your canner all hot and ready. You do not want to add the hot bottles to cold liquid. You will run the risk of shattering the bottles. Hot liquid in bottles, hot liquid in canner is a winning combination. Well, at least not a shattering one.
Blend the tomatoes before straining. Blend thoroughly.