Canned tomato sauce

Ingredients

Preparation

1. Wash the Mason jars, lids and bands in hot, soapy water, then rinse well. Keep the jars clean and hot until ready to fill to prevent thermal shock when adding the hot tomato purée.
2. Wash and dry the tomatoes. Cut them in two to make sure they are not spoiled inside. Put one large bucket on each side of the tomato press—one to collect the pulp and juice, and the other to collect the skin and seeds. Press the tomatoes. Run the skin and seeds through the press two more times to extract as much juice and pulp as possible. Throw out or compost the skin and seeds. Pour the juice and pulp into a pot on the propane cooker. Repeat until all of the tomatoes have been pressed.
3. Set the propane cooker to high heat. Bring the juice and pulp to a boil, reduce the heat to medium, and continue cooking for about 1 hour or until a thick, chunky texture is obtained. Stir and skim the surface regularly.
4. Place a few basil leaves in the bottom of each jar, then fill with the hot tomato purée, leaving about 1 cm (½ inch) of headspace. Wipe the rim of each jar with a clean cloth. Place the lid and band on each jar and tighten the band until fingertip-tight, without overtightening.
5. Place the jars in the pressure canner according to the manufacturer's instructions and add the recommended amount of water. Lock the lid and bring the canner up to pressure. Process the jars for the time recommended in your pressure canner's instruction manual, based on the jar size and your altitude.
6. Once the processing time is complete, allow the pressure to return to zero naturally before opening the canner. Remove the jars and place them on a towel, undisturbed, for 12 to 24 hours. Check that the lids have sealed properly: the centre of each lid should be concave and should not flex when pressed. If a jar did not seal properly, refrigerate it and use within 3 to 4 days, or transfer the tomato purée to a freezer-safe airtight container before freezing.