The Declaration of Independence and the Magna Carta were both penned with oak gall ink. It’s a good thing too, as this ink lasts longer than many of its counterparts. A well-made gall oak ink takes centuries to fade, though it can in certain conditions. It usually turns brown and a little blurry which can make it difficult to read.

History of Oak Gall Ink

Oak gall ink started in the Roman days around the 4^th century and became widely used in the Medieval Christian Era when scribes would carry a kit that included an inkhorn full of gall ink, several quills, and a pen knife to cut points on said quills.

Fresh quills were important because oak gall ink has a corrosive nature. In fact, poorly made ink from oak galls could literally eat through a page. Talk about losing your work!

How to Make Oak Gall Ink

People today are still making ink in the old ways. The Huntington had a great blog on how they make ink.

1. Collect oak galls.
2. Dry, then pulverize the oak galls.
3. Add water and bring to a boil.
4. Filter the brown liquid through a cloth.
5. Add a teaspoon of iron sulfate and watch as the mixture blackens. (This is caused by the chemical reaction caused by adding iron to the tannins.)
6. Thicken the ink by adding gum arabic.

What is an Oak gall?

Oak galls are created when an oak gall wasp secretes a chemical onto a leaf and causes the tree to create an abnormal growth pattern. The wasp lays eggs that hatch, grow up, and fly away, leaving a ball-shaped plant material on the back of the leaf.

These galls have a lot of tannins in them, which is the first component of this ink. A person would only need to pick a dozen to dry and make a good-sized bottle of ink. They could also harvest during drought years and store away to use on years where rain is more abundant, and trees are less suspectable and make less galls.

What is Iron Sulfate?

Iron Sulfate is a product of iron that has been passed through sulfuric acid, creating a green crystalized substance called ferrous sulphate. Many historical recipes record it as vitriol or copperas and recommend throwing an iron nail into the mixture as a way of gaining the necessary chemical reaction.

People also can use iron pots to boil the galls which gains the same effect. Perhaps this was why it was hard to create “good ink” and some batches would eat through their vellum.

What is gum Arabic?

Gum Arabic-also known as Acacia gum-is made from the sap of the Acacia tree. This tree tends to grow in arid areas like Sudan and Australia, so likely it was imported to scribes in the northern areas. However it got there, it was highly prized. It is used as a thickening agent to help the ink flow smoothly and give a longer writing time between dips.

Using Oak Gall Ink

The ink is corrosive in nature, so many people now prefer to use dip pens or quills and avoid using it in their fountain pens. When it flows onto the page, it looks like a translucent blue but darkens into a black color as it dries.

Try it!

Want to try it without gathering wasp nurseries? You can purchase oak gall ink online. If you want to try and make it, Realselfsufficiency has a good article that goes in depth. And at the least, next time a kid asks you what the balls on the back of the leaves are, you’ll have a ready answer.