Concerning the Creation of Ink from Oak Galls
February 2022
A visual diary of my thoughts regarding the rendering of ink from collected oak galls.
Historical exemplar
A Booke of Secrets: Shewing diues waies to make and prepare all sorts of Inke, and Colours. London, Adam Islip, 1596
"To make inke to write upon paper
Take halfe a pint of water, a pint wanting a quarter of wine, and as much vineger, which being mixed together make a quart and a quarter of a pint more, then take six ounces of gauls beaten into small pouder and sifted through a sive, put this pouder into a pot by it selfe, and poure halfe the water, wine and vineger into it, take likewise foure ounces of vietriall, and beat it into pouder, and put it also in a pot by it selfe, whereinto put a quarter of the wine, water, and vineger that remaineth, and to the other quarter, put foure ounces of gum Arabike beaten to pouder, that done, cover the three pots close, and let them stand three or foure daies together, stirring them every day three or foure times, on the first day set the pot with gaules on the fire, and when it begins to seeth, stir it about till it be throughly warme, then straine it through a cloath into another pot, and mixe it with the other two pots, stirring them well together, and being covered, then let it stand three daies, til thou meanest to use it, on the fourth day, when it is setled, poure it out, and it wil be good inke.
If there remaine any dregs behind, poure some raine water that hath stand long in a tub or vessell into it, for the older the water is, the better it is, and keepe that untill you make more inke, so it is better then clean water."
Lehner, Sigmund. Ink Manufacture. London, Scott, Green, & Son, 1902
""The larger part of the water is poured boiling over the crushed galls, which are then allowed to ferment for two months. The liquid is then drawn off, and the residue is rinsed with the rest of the water. The two solutions are filtered together and the gum is dissolved in the filtrate. The vitriol is then added in the form of concentrated solution. "
Build Process
There exist many readily available recipes and preparations of ink online. I was intrigued by the idea of a fermentation as described by Lehner. For my first attempt I used a basic recipe of 8 parts by weight Galls, 4 parts by weight Vitriol, 2 parts by weight Gum Arabic, 64 parts by weight water. Most historical recipes call for rain water or wine, I chose to use distilled water, just to eliminate variables while i tried to fine tune ratios and process. That first attempt went poorly, I ended up having to add a multitude more vitriol and gum arabic, and evaporate down the ink to get a consistency which was more ink and less watercolor.
My second attempt was much more methodical and documented below.
Ingredient #1 - Oak Galls
From Wikipedia: "Oak apple or oak gall is the common name for a large, round, vaguely apple-like gall commonly found on many species of oak. Oak apples range in size from 2 to 4 centimetres (1 to 2 in) in diameter and are caused by chemicals injected by the larva of certain kinds of gall wasp in the family Cynipidae. The adult female wasp lays single eggs in developing leaf buds. The wasp larvae feed on the gall tissue resulting from their secretions, which modify the oak bud into the gall, a structure that protects the developing larvae until they undergo metamorphosis into adults.
Considerable confusion exists in the general literature between the oak apple and the oak marble gall. The oak marble is frequently called the oak apple due to the superficial resemblance and the preponderance of the oak marble gall in the wild. Other galls found on oak trees include the oak artichoke gall and the acorn cup gall, but each of these has its own distinctive form."
In the area of Virginia surrounding the Rappahannock River we have Oak Marble Galls, each of these are about 1-2 cm in diameter.
Ingredient #2 - Green Vitriol
Copperas
Iron(II) sulfate heptahydrate
ferrous sulfate
FeSO4·7H2O
This beautiful blue/green iron salt is the magical chemical which will create the deep black ink. It is a naturally occurring mineral, However due to ease this was purchased from a chemical supply house.
Ingredient #3 - "Gum Arabike"
Gum Arabic. The powdered sap of the acacia tree. In this ink, it is used as a thickening agent, and as a binder to help the ink particulate to remain in suspension.
Preparing the galls
To begin this process, the galls must be crushed. Historically this would be done with a motor and pestle, however, they are incredibly dense. To speed the process I chose to use a coffee grinder to get the galls reduced to a fine powder. The finder the grind, the more surface area and the better the fermentation to convert the tannins.
Fermentation of Gallotanic Acid
Oak Galls contain high levels of Tannins. A fine powder of galls allows the tannins to better dissolve into water, creating a solution of Gallotannic Acid. Gallotannic Acid will react with Green Vitriol to make ink. However, by encouraging naturally occurring fungi and bacteria to ferment the gall powder, the sugars and gallotannic acid will be converted to Gallic Acid. Gallic Acid will produce a much better reaction with Green Vitriol to produce a more stable ink.
The fermentation process takes between 2-4 months. I am beginning to believe that the quantity of water I have thus far added to this step is far too much. That adding just enough of the measured quantity of water to moisten the gall powder and allow the fungus to bloom may produce a better yield. However, this hypothesis is yet untested by me.
Filter the gall juice
The goal is to remove all solid material from the solution of fermented galls. In this batch I had done multiple filtrations. First through paper towels, then through coffee filter. I have since found that allowing more time for the process, and doing a single, very slow filtration through coffee filter produces a far more clear result.
As each filter filled with gall grounds it would be removed and set aside.
After all the liquid was filtered, the removed grounds were collected in a separate container and the remainder of the measure of water was poured boiling over top the separated grounds. The grounds were allowed to sit for 5 minutes then filtered a final time.
Filter the gall juice 2
In this batch, rushing the filtration resulted in a muddier solution, requiring another filtration. The end result should be a transparent, deep rich brown without much if any haze to it.
Perform Alchemy
Measure the Vitriol by weight, and add to the Gall Juice solution. As soon as they are mixed the solution will become a deep black with a very fine particulate floating in it. The particulate is what is forming our ink, if allowed to sit, it will settle out of suspension. This requires a binder, time to grab the Gum Arabic. Measure and add to the proto-ink solution. Agitate heavily. In an ideal world a stir plate with stir bar would be perfect. I chose to be more historically accurate and shook the mixture viciously for 30-60 seconds a few times a day for 4-6 days.
A secondary addition of Clove oil is added at this point, 5-10 drops to slow the growth of any remaining fungi or bacteria.
Final Product
Lessons Learned
This is an ongoing project. Volumes and precise methods are tweaked each time I attempt this.
Replacing the rinse water with vodka has had no negative interactions, and should help with shelf stability of the final product.
After the addition of vitriol do not attempt to filter again. the separation of the particulate from the solution creates a mess which can not easily be returned from. To thicken an ink allow to evaporate for a few weeks.