How to Make Oak Gall Ink: A Traditional Recipe for Modern Makers
Oak galls may look like small, woody marbles, but their high tannin content makes them one of the most fascinating natural materials for traditional ink making. Mixed with an iron source, they create a deep grey-black ink that has been used for writing, drawing and manuscripts for centuries.
This oak gall ink recipe is designed as an approachable project for modern makers. The method is simple, but a little patience makes a noticeable difference to the colour and flow.
If you are new to galls, start with Oak Galls Explained: From Nature to Practical Uses. It covers how they form, the different types you may find and how to collect them responsibly.
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What Is Oak Gall Ink?
Oak gall ink, often called iron gall ink, is made by combining tannins extracted from oak galls with iron. The reaction produces a dark liquid that continues to deepen as it is exposed to air.
Freshly mixed ink can look grey or bluish-black. On paper it gradually oxidises into a richer, darker shade. That slow transformation is part of the appeal: this is not a perfectly uniform commercial ink, but a living botanical material with subtle variation.
Traditional formulas vary widely. Some were made for scribes and formal documents, while others were mixed more loosely for sketching or mark-making. The recipe below keeps the quantities manageable for a first batch.
When and How to Collect Oak Galls
Look for mature galls from late summer into autumn, particularly beneath English oak or sessile oak trees. Choose dry, firm galls without mould or soft patches.
Small round holes usually indicate that the gall wasp has already emerged. These are the best galls to collect because the insect has completed its life cycle.
Collect only what you need and leave plenty in place. Carry them home in a paper bag rather than sealed plastic, then allow them to dry fully before storage.
Don’t Have Access to Oak Galls?
You can also use ready-ground oak gall powder. This saves the crushing stage and can produce a more consistent extraction, making it particularly useful for first-time ink makers.
Check that the product contains pure oak gall powder without added dyes or other ingredients. Quercus infectoria powder can be especially rich in tannins, so begin with approximately 10 g of powder for this small batch and adjust future batches based on the colour and flow.
What You Will Need
4–5 dried oak galls or approximately 10 g pure oak gall powder
120 ml or ½ cup warm distilled water
½ teaspoon iron sulphate, or a few clean rusty iron nails
½ teaspoon gum arabic powder
A glass jar with a lid
A mortar and pestle, hammer or dedicated grinder
A fine sieve, muslin cloth or coffee filter
A second clean glass jar or small bottle
Gloves and protective eyewear
A dip pen or brush for testing
Use equipment reserved for craft projects rather than food preparation. Oak galls are hard and can splinter when crushed, so wrap them in a folded cloth if you are using a hammer.
How to Make Oak Gall Ink
Break the dried galls into smaller pieces. Crush them as finely as you reasonably can; a coarse powder exposes more surface area and helps release the tannins. If you are using ready-ground oak gall powder, skip the crushing stage and place the powder directly in the jar.
Place the crushed galls in a glass jar and add the warm distilled water. Close the lid and leave the mixture to steep for 24–48 hours. For a deeper extraction, leave it for several days and shake the jar gently once a day.
Strain the liquid through muslin, a coffee filter or a fine sieve into a clean jar. Press gently to recover as much of the tannin-rich liquid as possible.
Put on gloves. Add the iron sulphate a little at a time and stir. The liquid should darken almost immediately. If you are using rusty nails, add them to the strained gall liquid and allow the mixture more time to react.
Add the gum arabic gradually, stirring until it dissolves. This improves flow and helps the ink sit more evenly on paper.
Transfer the finished ink to a labelled glass bottle with a tight-fitting lid. Test it with a dip pen or brush and note how the colour changes as it dries.
Using Rusty Nails Instead of Iron Sulphate
Rusty nails offer a slower, less predictable alternative to measured iron sulphate. Place several clean, uncoated iron nails in a small jar and cover them with vinegar. Leave them until the liquid develops a rusty colour, then add this iron solution to the oak gall extract drop by drop.
This approach suits experimental art and seasonal craft projects, where slight differences between batches are part of the charm. If you want a more repeatable ink for calligraphy, iron sulphate gives you better control.
Never use galvanised, painted or chemically coated metal.
How to Adjust the Consistency
Homemade ink rarely behaves perfectly on the first test. Make small adjustments rather than adding large quantities at once.
If the ink is too pale, allow it to oxidise for longer or add a very small amount of iron solution.
If it is too watery, add a little more dissolved gum arabic.
If it feels sticky or drags across the paper, dilute it with a few drops of distilled water.
If particles remain, filter the ink a second time.
Test each adjustment on the same type of paper. Absorbent handmade paper will behave differently from smooth drawing or calligraphy paper.
How to Use Oak Gall Ink
Oak gall ink is particularly satisfying for botanical sketching, handwritten labels, dip-pen practice and loose brushwork. Its colour can shift from soft grey to deep charcoal-black, giving drawings a naturally aged quality.
Try it for:
Botanical studies and nature-journal pages
Dip-pen writing and decorative lettering
Handmade gift tags
Monochrome brush paintings
Pattern experiments on watercolour paper
Use a dip pen rather than a fountain pen. Homemade particles and sediment can block the internal feed of a fountain pen.
Does Iron Gall Ink Damage Paper?
Traditional iron gall ink can become acidic, particularly when a recipe contains too much iron. Historic documents sometimes show browning, cracking or holes where the ink has slowly damaged the paper.
For a small creative batch, measure the iron carefully and use only enough to achieve a good dark colour. Treat the finished ink as an art material rather than an archival product. If longevity matters, test the ink first and use good-quality, acid-free paper.
Storing Your Homemade Ink
Keep the ink in a clearly labelled glass bottle away from heat and direct sunlight. Make small batches that you can use while fresh.
A clean bottle and distilled water help reduce contamination, but natural ink can still spoil. Discard it if you notice mould, an unusual surface film or a distinctly unpleasant smell. Do not pour unused ink back into the storage bottle after dipping a used brush or pen into a separate working pot.
A Quiet Botanical Craft
Making ink from oak galls turns an easily overlooked woodland object into something practical and expressive. The process is part foraging, part chemistry and part slow craft: collect, crush, steep, wait and watch the colour change.
No two batches will be exactly alike. Keep a simple record of your proportions, steeping time and paper tests so you can refine the result next time.
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Frequently Asked Questions
Can I make oak gall ink without iron sulphate?
Yes. A solution made with rusty, uncoated iron nails and vinegar can provide the iron, although the result is slower and less consistent.
Do oak galls need to have exit holes?
Galls with small exit holes are preferable because they show that the gall wasp has already emerged. Avoid collecting fresh occupied galls.
Can I use a fountain pen with homemade oak gall ink?
No. Sediment can clog the feed, and the iron content may damage internal parts. Use a dip pen or brush instead.
Why is my oak gall ink grey rather than black?
It may need more time to oxidise, a stronger gall extraction or a tiny amount more iron. Adjust gradually to avoid making the ink overly acidic.
How long does homemade oak gall ink last?
Storage time varies because it is a natural, small-batch material. Keep it sealed, cool and dark, and discard it if you see mould or notice spoilage.
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