Step 1

Trim, quarter, and place tomatoes into a large stockpot. Bring to a boil stirring occasionally.

Step 2

When tomatoes have softened, either blend with a hand blender or run through a food mill. If using a food mill the skins and seeds can be discarded. Reserve 1 cup of tomato juice (for thickening later.) Simmer down to about half the liquid* (2-3 hours.)

Step 3

Add the vinegar, tomato paste, sugar, and spices; bring to a simmer.

Step 4

Meanwhile, place 1/3 cup of Thermflo into a bowl. Slowly whisk in the reserved tomato juice and whisk into the simmering tomato ketchup.

Step 5

Pour ketchup into jars and place lids and bands on, (don't screw tightly shut.) Place jars into a large stockpot. Pour hot tap water in at least halfway up. Boil 10 minutes covered from the time the water boils.

Step 6

Remove jars with a jar lifter and screw each jar tightly shut using a kitchen towel. Check if the lids are sealed AFTER 24 hours (they need to seal on their own first.)