Dustin Bajer, Making Walnut Ink

Making Walnut Ink and Dye

Making Ink and Dye From Walnut Seeds

I discovered walnut ink while collecting and processing (dehusking) walnuts to plant with the Shrubscriber community.

Locally, the most common Walnut is the White or Butternut Walnut (Juglans cinerea but I occasionally run across Black Walnuts (Juglans nigra) and Manchurian Walnuts (Juglans mandschurica). I gather seeds, a process I call “playing squirrel,” by knocking ripe nuts from the tree using a telescoping painter’s pole.

Dustin Bajer, Jessica Peverett collecting walnuts at the University of Alberta
Using a painter’s poll to collect walnuts at the University of Alberta.

Walnuts have a sticky green husk surrounding a single seed. I had been discarding the husks for years until I learned you could make walnut ink from them! While not 100% necessary, I find that I get better germination when I remove the husks; I used to do this by hand, but it’s time-consuming and dyes my fingers black.

The Research

I jumped online a found three posts describing how to make walnut ink. While each set of directions varied, they followed the same basic steps; soak, boil, filter, and preserve. The following steps are my take on the process and an average of the four sources I found.

Walnut Ink Recipe

I’m mainly after the seeds – the ink is a bonus for me, so, unlike some of the instructions above, my process emphasizes saving the seeds so I can plant them.

Material List

  • 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. Husks start green and oxidize to a greasy brown/ black. The exact species (White, Black, Mancuriaun, etc.) doesn’t seem to matter – you’re looking for any plant in the genus Juglans.

Dustin Bajer, Oxidized black walnuts for making walnut ink
Oxidized Black Walnuts for making walnut ink

Like an apple, walnut husks oxidize when exposed to air, and we’re after this brown/black pigment. Removing green husks is difficult, so I lay them out on a try until they start turning brown and get soft to the touch.

How many nuts? As many or as few as you’d like. The more nut you use, the more ink you’ll make.

Step 2 – Soak

Find a large pot to hold your gathered walnuts and toss them in. Add enough water to cover the nuts and let them soak at room temperature. Stir them now and again. 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.

Step 3 – Remove the Seeds (Technically Optional)

This step is optional Unless you plan to save and plant the seeds. I’m in this for the baby trees, so the thought of boiling a pot of walnuts that could turn into three-hundred-year-old trees hurts my heart.

I remove the seed but leave the husks in 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 this step has more to do with concentrating the pigment than any chemical reaction or extractive process – but I’m not a chemist. In either case, the time it takes to reduce the volume of liquid by half will depend on how much water you have to start.

I recommend doing this step outside. I like the smell of boiling walnut husks, but the humidity and the potentially sticky residue are enough to convince me to go outside.

Once the volume has reduced by half, take your inky mush of the heat to cool. I let mine sit overnight.

Step 5 – Strain Out the Big Bits

Now that your inky mush is at room temperature, it’s time to remove the husks. A colander, sieve, or cheesecloth is an excellent first pass. I used a nylon straining bag inside a pail. Things can get messy, and remember that we’re making ink – lay down some plastic and wear gloves.

Step 6 – Filter Out the Small Bits

At this point, the walnut ink will be reasonably clean and is probably usable, but I decided to run it through a large coffee filter for a final polish. It was filtering fine particles because I probably went through 6 or 7 coffee filters in the end.

Dustin Bajer making walnut ink, filtering homemade walnut ink through a coffee filter
Filtering walnut ink through a coffee filter

Step 7 – Preserve or Refrigerate

Congratulations, you’ve made walnut ink! Keep your ink in the fridge, or add a few drops of antimicrobial essential oil like Wintergreen to preserve your ink. A second suggestion is to add rubbing alcohol to your ink to 20% of the volume. Adding alcohol will dilute the ink but lower its evaporation point – helping it dry. I like to keep things simple, so I stored mine in the fridge.

Step 8 – Thicken Your Ink (Optional)

Walnut ink is less viscous than modern commercial ink. If it’s too runny for your liking, add gum arabic to thicken it. Gum arabic is the hardened sap from the acacia tree. I opted to leave mine unthickened because I gave my ink to local artists and members of the Shrubscriber Community and I’ll let them decide how thick they want it – mostly, I don’t have gum arabic or acacia trees on hand.

Dustin Bajer, jars of homemade black walnut ink
Jars of homemade black walnut ink

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’s it! You’ve made ink from walnuts! Use your ink for your next art project or to dye textiles. Please send me a picture of your project! If you follow this recipe, let me know how it turns out!

Making Walnut Ink the Movie

If you’d like a closer look at the ink and dye-making process, I filed the entire thing and put together this short video.

Making Walnut Ink, The Movie