My next walnut project is to try to make walnut ink. I discovered this substance when learning calligraphy and it makes glorious marks. It's also relatively expensive, so it seemed like a good idea to try to make my own. I researched it on the internet a couple of years ago, made a batch, and when all the work was over, discovered that it was too thin and made too pale a line. I stashed it in a safe place and thought that maybe it would continue to evaporate over time, but the place is so safe that I can't find it and check out my hypothesis.
For some of the day it simmered over low heat. When we got ready to leave the house, I would turn up the heat for a couple of minutes, then turn if off while we left. I suppose that it cooked for five or six hours.
By then, the ink was thick and syrupy and when I tested it in a pen, it was even darker than the commercially bottled ink I had just bought at the art supply store, so I decided it was done.
I pulled the walnuts out of the pot, wrapped them in some white fabric and stashed them in a plastic bag. I strained the ink through another piece of fabric to get rid of any bits of nut or husk.