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Iron gall (blue-black) ink

The main components of this ink are the oak galls and the Iron (II) sulfate (T). These together provide the black colour of this ink. Immediately after writing the ink is in general quite light: greyish, it turns darker after a few days.
We do not use a preservative: the ink is so acidic that the risk of mold formation is minimal.


– 10 grams of oak galls
– 5 grams of Iron (II) sulfate (T)
– 4 grams of Gum Arabic
– 250 ml tap water

It is best to put the gum Arabic in 50 ml of water the day before. During the night the gum dissolves in the water. Any residues are contamination of the gum and you can remove it with a tea strainer or, if necessary, a coffee filter.

Cut the oak galls in half. Boil the chopped oak galls in about 200 ml of water for 10 minutes. To get the clearest possible ink, the cooking liquid is poured off and then filtered through a coffee filter. Let the coloured liquid cool and dissolve the iron sulphate in it. Finally, add the gum solution.
Put the ink in a well-sealed bottle, it is ready for use. Some precipitation will probably settle on the bottom over time, but that can’t hurt.