It’s actually possible to create your own edible ink by reducing any water-based and edible liquid. To do so, simply simmer a natural liquid (you can either use fruit or veggie juice) to lower its water content and create a darker and more viscous fluid.
To start, pour an edible liquid to a saucepan then cover it with a lid. You can go for red wine or prune juice if you want a darker color. After that, set it to medium heat then bring to a boil. In most cases, it will only take you a few minutes to boil a cup of water-based liquid.
Once it starts boiling, you can then reduce the heat and remove the lid on the saucepan. Continue stirring the liquid for around 10-15 minutes or until it gets reduced to approximately 2 tablespoons.
Remove the saucepan then pour the edible ink into a small bowl. Use a spatula to transfer every single drop with ease. Then, place it on top of an ice pack in your fridge and allow it to cool for 15 minutes.
Once the ink has cooled enough, you can then apply it to the surface of a food you want to color in a single thin coating. Allow it to dry for around 30 seconds before you apply another layer. Make sure to store unused ink in the fridge and cover it with a piece of plastic wrap. Keep in mind that the ink will only last up to two weeks; you will have to discard it after that.