1. Purchase wide-mouth, quart-size canning jars. Remove rings and lids from jars. Place jars only in the dishwasher and run through a complete cycle to sanitize. Leave them in the dishwasher until you are ready to use them.
2. Wash and dry one bushel of tomatoes. Cut out the stems on the top. Roughly chop tomatoes in large chunks.
3. Place chunks in large pots (avoid aluminum). Bring the pots to a boil, then turn down to medium heat.
4. Continue to stir occasionally until tomatoes break down. There will be a lot more juice in the pot than when you started.
5. Run contents of each pot through a food mill or Squeezo. Place juice back in the pots and bring back to a boil.
6. While juice is coming back up to temperature, remove canning jars from dishwasher. Put 1 teaspoon of kosher salt and 1 teaspoon of citric acid in the bottom of each jar.
7. When tomato juice is hot, quickly ladle it into the awaiting jars (or use a funnel) until you reach the lower lip of the jar.
8. Place the lid on top of the filled jar and screw on the ring. Let the jars rest on the counter for several hours.
9. Once jars are cool, push down on the lid. If it does not spring back, the jars are completely sealed and ready to store.