Step 1

Boil a pot of water and prepare the ice bath. Bring a large 6-quart or larger Dutch oven or stockpot of water to a boil over high heat. Fill a large bowl with ice and water and set this next to the stove.

Step 2

Prepare the tomatoes for blanching. Core out the stems from the tomatoes and slice a shallow "X" in the bottom of each fruit.

Step 3

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. Using a slotted spoon, lift the tomatoes out and place them in the ice water. Continue with the rest of the tomatoes, transferring the cooled tomatoes from the ice water to another large bowl as they cool. Pour the blanching water from the pot (no need to dry).

Step 4

Peel the tomatoes. When finished blanching, use your hands or a paring knife to strip the skins from the tomatoes. Discard the water used to boil the tomatoes.

Step 5

Coarsely chop the tomatoes. Working in batches, place the tomatoes in the food processor fitted with the blade attachment. Pulse a few times for chunkier sauce, or process until smooth for a puréed sauce. Alternatively, chop the tomatoes by hand. For a smoother sauce, process through a food mill. For a very chunky sauce, skip this step entirely and let the tomatoes break down into large pieces as they cook. Transfer each batch into the reserved Dutch oven or stockpot.

Step 6

Simmer the tomatoes. Bring the tomato sauce to a simmer over medium heat. Continue simmering, stirring occasionally, until the sauce reaches the taste and consistency you like, 30 to 90 minutes.

Step 7

Stir in the lemon juice and salt. Stir in at least 1/4 cup of the lemon juice or vinegar and salt. A 1/4 cup is necessary to ensure a safe level of acidity for canning. Taste and add more lemon juice or vinegar as needed.

Step 8

Preserving Option 1: FreezingLet the sauce cool, then transfer it into freezer containers or freezer bags. Sauce can be kept frozen for at least 3 months before starting to develop freezer burn or off-flavors.

Step 9

Preserving Option 2: CanningTransfer 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. Let cool completely on the counter — if any lids do not seal completely (the lids will invert and form a vacuum seal), refrigerate that sauce and use it within a week or freeze it for up to 3 months. Canned tomato sauce can be stored in the pantry for at least 1 year.