Use a large bowl and have a spatula or large spoon ready to mix the ingredients. You can also use a mixer if you prefer.
Add all the ingredients into your bowl, one by one, then mix with the spatula until well incorporated.
Add water a little bit at a time, if needed, to reach the correct consistency. Just aim for what you know ketchup consistency to be. It should be slightly liquid and look less like a paste.
Taste and adjust seasonings to your preference.
Add ketchup to a clean Mason jar and fill to the top of the jar.
Use a clean cloth to wipe the rim of the jar.
Place a canning lid and band on top and screw it on, but not completely tight. You want some of the air to escape in the fermenting process.
Let it sit on the counter for 6 to 10 hours, then put it in the refrigerator.
Let it chill; then, it will be perfectly suitable to use as regular ketchup.