Iron gall (also known as oak gall ink) has an incredible history. First mentioned in the writings of Roman author and naturalist, Pliny the Elder (b. 23 CE - d. 79 CE) this purple-black ink is made from tannins extracted from oak galls and iron salts.
Britain's oak trees support around 70 different species of gall wasps. These fascinating creatures have complex life cycles with alternating generations that are either all female and asexual, or sexual with male and female wasps. It is the larval stage of these insects that induce the plant to produce the abnormal growths (galls) that enclose the developing larvae.
Gall wasps cause no long term harm to the tree, and the galls vary according to species or even the generational stage at which the wasp lays its eggs.
A single tree can often produce different types of gall on different parts of the tree while some single species will swap between native and non-native species of oak depending on their alternating generations.
Our ink is made using knopper galls from our oak tree in East Quantoxhead, West Somerset. The galls are crushed and then soaked in rainwater to extract the tannins. This soaking process usually takes about 7 days, and then the mixture is filtered through unbleached paper filters. At this stage, a measured amount of iron sulphate and gum arabic is added.