Roasting tomatoes for canning

Some home canning recipes for tomato-based products have started calling for the tomatoes to be roasted as part of the prep. The process works best with large, paste-type tomatoes such as Roma, San Marzano, and Amish Paste, etc, but it can also be done with other tomatoes.

Course Side Dish
Cuisine American
Keyword Tomatoes
Prep Time 2 hours
Cook Time 1 hour
Yield 1 varies
Calories 18 kcal



  1. Using a paring knife or other tool of your choice, cut out the cores of the tomatoes, then slice them in half vertically.
  2. Place cut-side down on ungreased, rimmed baking sheet.
  3. Roast for 45 to 50 minutes at 225 C (450 F).
  4. Let cool (see note below about freeing up baking sheet.)
  5. When cool, leaving the tomatoes lying flat, proceed to simply pinch the skins off them by pinching towards the centre. If skin isn't coming off the tomatoes effortlessly, they needed to be roasted longer.
  6. Collect skinned tomato halves.
  7. Flick off any hard black carbonated bits on them from the pan (soft charred roasted pieces are fine to leave,)
  8. Discard any liquid left on the tray (or refrigerate in a tub for use with crushed tomatoes, juice, etc.) You don't want that in the sauce, it will make it watery.
  9. Pass through a sieve or food mill for a smooth sauce. Or whiz through a food processor for a rustic, chunkier sauce with seeds. (The tested recipe you are following will advise.)