Making Medieval Ink – Oak Galls

Oak apples / oak galls are always a great talking point along the way on my walks. Created by an oak gall wasp whose eggs are laid on parts of the oak tree, more often twigs. The tree responds to the eggs by producing growth around the egg. The wasp has developed a very interesting method for the larvae to grow into a wasp and fly away (zoom in you can see the exit hole).

There are a large number of species that do this (Biorhiza pallida, Andricus kollari – are the most common recognised on walks as “oak apples”). This is a pretty cool process and the process of making ink from these oak galls is a really great thing to do.

The oak galls are really high in tannins so by grinding them up and placing them in rain water then left over night is the start of the process. Typically the tannins were extracted by fermentation and then mixed with iron sulphate (works with iron rust) to create an ink. I simply use rust and rain water and it works fine. If you don’t want to collect rust you can buy iron sulphate from a garden centre.

Documents such as the Magna Carta were written in oak gall ink which was used up until the 20th century. A little video on this for this mid-week I think.

Documents such as the Magna Carta were written in oak gall ink which was used all the way up until the 20th century. This is one of those cool things I love to discuss on my walks and events.