15 pounds ripe tomatoes
1/4 to 1/2 cup lemon juice or red wine vinegar
2 teaspoons salt (optional)
Boil a pot of water and prep the ice bath: Bring a large Dutch oven or stockpot of water to a boil over high heat. Fill a mixing bowl with ice and water and set this next to the stove.
Prepare the tomatoes for blanching: Core out the stems from the tomatoes and slice a shallow “X” in the bottom of each fruit.
Blanch the tomatoes to peel them: Working in batches, drop several tomatoes into the boiling water. Cook until you see the skin starting to wrinkle and split, 45 to 60 seconds, then lift the tomatoes out with the slotted spoon and plunge them into the ice water. Continue with the rest of the tomatoes, transferring the cooled tomatoes from the ice water to another mixing bowl as they cool.
Remove the peels from the tomatoes: When finished blanching, use your hands or a paring knife to remove the skins from the tomatoes.
Roughly chop the tomatoes: Working in batches, pulse the tomatoes in the food processor. Pulse a few times for chunkier sauce, or process until smooth for a pureed sauce. Transfer each batch into the Dutch oven or stockpot.
Simmer the tomatoes: Bring the tomato sauce to a simmer over medium heat. Continue simmering for 30 to 90 minutes, stirring occasionally, until the sauce reaches the taste and consistency you like.
Stir in the lemon juice and salt: When finished cooking, stir in the lemon juice or vinegar and salt. A quarter-cup is necessary to ensure a safe level of acidity for canning. Add more lemon juice or vinegar to taste.
Transfer the hot sauce into sterilized canning jars. Top with new, sterilized lids, and screw on the rings until finger tight. Process in a pot of boiling water for 30 minutes.