Select Tomatoes: Use 7 lbs of ripe Roma tomatoes for their low moisture and easy-to-remove skins.

Wash: Rinse tomatoes thoroughly under warm water, removing dirt and inspecting for ripeness and blemishes.

Core and Chop: Use a sharp knife to remove the cores. Chop the tomatoes into ½-inch cubes.

Smash Tomatoes: Place chopped tomatoes in a large stainless steel pot. Use a potato masher to crush and release their juices.

Cook: Bring the tomatoes to a boil over medium-high heat. Stir frequently to prevent scorching. Reduce heat and simmer for about 1 hour, stirring regularly. The volume should reduce by 50%.

Strain: Pass the cooked tomatoes through a food mill to remove skins and seeds. Discard the remnants in the mill.

Acidify: Return the strained tomatoes to the pot. Add ½ tsp citric acid and ½ tsp salt, stirring to combine.

Reduce Further: Cook over medium heat for 2 hours, stirring regularly to prevent sticking. The mixture is ready when it’s thick and can hold its shape on a spoon.

Sterilize Jars: Inspect jars for cracks, wash with warm, soapy water, and simmer in your canner filled with water.

Heat Lids: Place lids in warm water on low heat to soften the adhesive.

Fill Jars: Remove jars from the canner using a jar lifter. Use a funnel to ladle paste into jars, leaving ½ inch of headspace.

Remove Air Bubbles: Run a knife or bubble remover along the jar's interior to release trapped air.

Clean Rims: Wipe jar rims with a damp paper towel to ensure a clean seal.

Apply Lids: Place lids on jars and screw rings until fingertip-tight.

Process: Place jars in the canner, ensuring they’re covered by at least 1 inch of water. Boil for 45 minutes, adjusting for altitude if necessary.

Cool: Turn off heat and let jars rest in the canner for 5 minutes. Remove jars with a lifter and place them upright on a towel. Allow to cool undisturbed for 24 hours.

Inspect and Store

Check Seals: Ensure lids are sealed by pressing the center. If it doesn’t flex, the seal is secure. Refrigerate any unsealed jars and use promptly.

Label and Store: Mark jars with the date and contents. Store in a cool, dark place for up to 1 year.