Homemade Black Walnut Ink

A couple of years ago, I ran across references to walnut ink on the Internet.  Intrigued, I did a little research, and discovered that an interesting dark brown ink can be made from the husks of black walnuts, so I set out to make my own.  Since I am asked about it fairly often, I have decided to include a description of the ink-making process on this site.  If you are at all interested, you should try it!  It's fun!

How to make your own ink:

Step 1. Find your walnuts. Black walnut trees are fairly plentiful here in Louisville, and that seems to be true for much of the eastern half of the U.S.  In October, one can spot the green, leathery, round fruit (usually just a little smaller than tennis balls) on the ground or getting ready to fall. One doesn’t use them when they are green, however. Gather the blackest, rottenest, gunkiest ones you can find. If there aren’t any that are black and icky, gather the green ones. Gather the entire fruit. The small, hard shell with the nut in the center is a non-essential piece for the ink. What one needs is the leathery rind. Just pick up the whole thing.

(Warning: Black, oozy walnuts will stain hands and clothing, so use some caution.)

Step 2. Put them in a plastic bag and let them rot. The green ones will turn black over a few days or weeks.

(Another warning: At any step in this process, one can set all these walnuts aside. They are already rotten; it’s not like putting one’s ink-making on hold for days or even weeks will ruin the batch. If you store the walnuts outside, however, critters will be drawn to them. Squirrels will tear open bags and gnaw on pots.)

I refer to the walnuts in disgusting terms, and they are pretty gross. They get slimy and moldy, and you’ll probably find all kinds of strange little bugs living in them. Don’t worry. It all cooks down to the same brown sludge. Except for those little pale brown beetle larvae. They stayed shiny and intact even after hours and hours of boiling. If the ick factor is too high, just remember that you must suffer for your art. So must those with whom you share your kitchen.

Step 3. After they are black, put them in a large pot for which you don’t have any great affection. I used a large aluminum pot that we use very infrequently. I was surprised that, after I was done, the pot cleaned up very well; other sources, however, say that their pots and pans can become discolored. Stainless steel or enamel-coated pots seem to be the general recommendation, but my aluminum one worked just great. Cover the walnuts with water and let them soak for at least a day. The longer they soak, the better. My first batch soaked for a day, and my second batch soaked for several days. I plan to make a third batch which I will allow to soak for several months.

(Another warning: The walnuts, water, and ink all have a high capacity for staining anything they come into contact with. This includes kitchen counters, fingernails, dishes, wooden spoons, and your clothing.)

Step 4. Dismantle the walnuts. Tear, mash, and break them up. The more little pieces one can get, the better. Remember, the rotten, black pulp material is the stuff that turns the water into ink. With my first batch, I tore them up before I soaked them. With my second batch, I didn’t really break up the husks until they were cooking. Step 4 can kind of be inserted anywhere in the soaking step, or early in the cooking step (Step 5.) Use this water, which at this point has started to turn black from the walnut juice, for the next step.

Step 5. With the walnuts still covered in their (now-blackened) water, put them on a medium-low heat. Let them simmer for a long time—hours. If the water gets too low, you can add more. The goal, though, is to let it slowly cook down. Periodically, dip a brush into it and test the liquid on some paper to see how dark it is. Once the liquid is as dark as you want it, your ink is nearly done. It has probably cooked down quite a bit by this point. The smell of the boiling walnuts is distinct, but not especially strong or unpleasant. It reminded me of rotten logs and damp forest.

 

Step 6. Let the dark brown mess cool for a while, and then strain it. The best method I’ve found so far is to stretch an old pair of nylons over a glass or plastic container, and pour the walnut sludge into it. Squeeze the sludge in the nylons to get as much liquid out of it as you can. Empty the walnut crumbs out of the nylons into the garbage (or your hedge, or compost heap, or your neighbor’s porch) and repeat until you’ve strained all the liquid into your container. Your container should now hold ink, free from all but small bits of sediment. This sediment, which will settle at the bottom of jars, shouldn’t be a problem.

Step 7. You might want to add a preservative, since the ink can grow mold. The best recommendation I’ve heard so far is to add a small amount of denatured alcohol (add it so that it constitutes 5% of the ink). Salt would also work, but salt can lead to corrosion in metal pen nibs. Vinegar also can retard mold and bacterial growth, but its acidity renders the ink non-archival. Optional: Most black walnut ink makers recommend the addition of gum arabic to improve the ink’s flow.

Sometimes art starts out sort of ugly...