Peel and deseed 4 quarts of tomatoes. Set aside.

Heat olive oil in a large sauce pot on medium heat until it starts to shimmer or is heated completely, then add in the green peppers, celery, and onion. Stir occasionally to coat with the oil and cook until soft. I usually cook until the onions are starting to go transparent. Then stir in garlic and heat an additional minute stirring to prevent garlic from burning on the bottom of the pot.

Pour in the four quarts of tomatoes and stir to combine. Add in Italian seasoning and Sherry and allow to heat through. Reduce heat when spaghetti sauce starts to bubble and splatter. Cook for approximately 2 to 3 hours until sauce is reduced stirring occasionally and keeping an eye on it to make sure it doesn't burn. Adjust heat accordingly.

If you would like a chunkier spaghetti sauce it's done when it reaches the consistency you are happy with. If you would like a less chunky spaghetti sauce use an immersion blender to blend the sauce to desired consistency.

Serve with pasta.