Making Ink and Dye From Walnut Seeds

I play squirrel each fall by collecting nuts from local walnut trees – sometimes using a telescoping painter’s pole with an attached 2-litre pop bottle to gently knock ripe nuts free from their branches. I make for an odd-looking squirrel. However, unlike the squirrels, I’m collecting nuts to plant into my urban tree nursery.

Located West and North of the native range of walnuts, Edmonton doesn’t have many walnut trees –  but you’ll spot them if you’re searching. The most common Walnut found locally is the White or Butternut Walnut (Juglans cinerea, E North America). However, I’ve seen a few Black Walnuts (Juglans nigra, E North America) and Manchurian Walnuts (Juglans mandschurica, E Asia) in smaller quantities.

When you collect a fresh walnut, it’s surrounded by a sticky green husk. To get at the seeds, I’d go through the time-consuming task of removing the husk – a process that would stain my fingers for weeks. Until recently, I discarded the flesh. Then I learnt that walnut husks could be used to make a dark brown/black ink or dye.

I jumped online a found four posts describing how to make walnut ink. While each set of directions varied, they all followed the same basic steps; soak, boil, filter, preserve. The following steps are my take on the process and an average of the four sources I found. While this process worked for me, I should emphasize that this was my first time making walnut ink. I am not an ink making expert, chemists, or ethnobotanist – so let me know if you have any advice. In no particular order, here are the instructions I came across in my research:

• Insightbb – Making Walnut Ink
• You Grow Girl – Make Your Own Black Walnut Ink
• Luna Toronto – How to Make Black Walnut Ink
• Alan Li Drawing – Hot to Make Walnut Ink

And Here’s My Walnut Ink Recipe

Remember, the seed is what I’m really after – the ink is a bonus for me, so, unlike some of the instructions above, my process emphasizes saving the seeds so that they can be planted.

Materials:

• Walnuts with husks
• A large pot
• Water
• Gloves
• Strainers
• Ladle
• Bowl or Bucket
• Jars
• Essential Oils, Rubbing Alcohol or a Refrigerator
• Gum Arabic (Optional)

Step 1 – Go Nuts

Collect as many husked walnuts as possible. The exact species (White, Black, Mancuriaun, etc.) doesn’t seem to matter – what you’re looking for is any plant in the genus Juglans. The flesh of Juglans seeds starts off green and will oxidize to a dark greasy-looking black. This is what’s going to give us our pigment.

The green husks will oxidize as soon as they’re exposed to air – like the browning of a cut apple – but a few of the instructions above suggested letting your walnuts turn brown/black before starting. It probably doesn’t matter, but the darker the husk, the easier it will be to remove them from the seed. So if you’re nuts are green, lay them out on a try until they start turning brown and getting soft to the touch.

How many nuts? As many or as few as you’d like. The more use, the more ink you’ll make. There’s no limit, but I probably wouldn’t do any less than a dozen as I’m not sure that the return would be worth the effort.

Step 2 – Soak

Find a pot large enough to hold the walnuts you’ve gathered and toss them in. Add enough water to cover the nuts and let them soak at room temperature. The water should start taking on colour right away. Soak them for a day or two – more if they’re green, less if they’re already black and falling apart. Stir ’em now and again.

Step 3 – Remove the Seeds (Optional… but is it?)

This is an optional step if you’re not planning on saving the seeds. Recall that  I’m primarily in this to grow walnut trees. The thought of boiling a pot of walnuts that could turn into three-hundred-year-old trees is too much for me to handle.

A bonus to the ink making process is that removing the seeds (from the now solf husks) breaks everything up and exposed more oxidizing juglans to the water.

Step 4 – Boil and Reduce

Directions for boiling ranged from 1 to 24 hours, but almost everybody said to reduce the volume of liquid by half – so that’s what I did. I suspect that this step has more to do with concentrating the pigment than any chemical or extractive process brought on by boiling – but then again – not a chemist. In either case, the amount of time it takes to reduce the volume of liquid by half will depend on how much liquid you’re starting with. This step took me around 2-hours.

I would recommend doing this step outside. It turns out that I enjoy the smell of boiling walnut husks, but the added humidity and potentially sticky residue is enough to convince me to go outside.

Once the volume has reduced by half, take your inky mush of the heat. Once the pot cooled, I brought it inside and let it sit for the night.

Step 5 – Strain Out the Big Bits

Now that your inky mush is at room temperature, use a ladle to run it through some strainers. A colander, sieve, or cheesecloth is a good first pass. I used a nylon straining bag inside a pail. Then, with my gloves on, I squeezed the ink from the walnut pulp.

Step 6 – Filter Out the Small Bits

The ink seemed fairly clean and probably usable, but I decided to run it through a large coffee filter for a final polish. It was obviously filtering something because I kept having to change the filter – I probably went through 6 or 7 of them.

Step 7 – Preserve or Refrigerate

At this point, we’re basically done, but walnut ink has a shelf-life and will mould (or so I’m told). To prevent spoilage, keep your ink in the fridge or add a few drops of antimicrobial essential oil like wintergreen. A second suggestion is to add rubbing alcohol – up to 20% of the volume – to your ink. This will dilute the ink, but alcohol’s lower evaporation point may aid it drying.

I opted to store mine in the fridge.

Step 8 – Thicken (Optional)

Walnut ink is less viscous than modern commercial inks. If it’s too runny for your liking, add gum arabic to preference. Gum arabic is the hardened sap from the acacia tree.

I opted to leave mine unthickened. Partially because I’m giving my ink away to some local artists and members of the Forest City Plants propagation class – I’ll let them decide how thick they want their ink – but mostly because I don’t have gum arabic or acacia trees on hand.

Step 9 – Jar

Almost any airtight container will work for holding your finished walnut ink. I used a few mason jars I had lying around and some honey jars for smaller samples. I like the honey jars because they’re reminiscent of old-timey inkwells.

And that it! You’ve made ink from walnuts! It’s worth noting that your ink can also be used to dye textiles. If you end up following this recipe, let me know how it turns out! Please send me a picture of your project!

Making Walnut Ink the Movie

If you’d like a closer look at the ink and dye-making process, I’ve put together this short video or each of the steps outlined above.