Chop the chili peppers and garlic cloves with a blender.
Tip: It is easier to process if you add a shot glass of water.
Put the water with sugar, vinegar and salt in a saucepan and bring to the boil until the sugar has dissolved. Then add the chilli mixture. Turn the heat down a little and simmer gently for about 5 minutes. Mix the cornstarch with a tablespoon of water and stir into the sauce.
Let everything simmer briefly until the mixture starts to become thicker. Now press the whole tube of tomato pulp into the pot. Bring it to the boil again briefly and then fill it into a sterile, good, sealable bottle.
When it cools, the bottle draws a vacuum and the ketchup can be kept for several weeks.