Creating everyday objects in the Middle Ages often took a lot time and effort. If you needed ink, for example, and had to make it yourself, it could be several weeks before you could dip your quill into the inkwell.
We know of several ways that people could make ink in the Middle Ages, since they have recorded their instructions on how to do it. The following recipe comes from Theophilus Presbyter, who in the early twelfth-century created a work known as De diversis artibus (On various arts). In it, Theophilus created detailed instructions about the techniques used in medieval art, with sections on paints and drawing materials, creating stained glass, and finally on metalwork. His book would have been a useful guide for any medieval artist who wanted to illuminate a manuscript, make a glass cup, or even build an organ.
Here is Theophilus’ chapter on making ink:
To make ink, cut for yourself some wood of the hawthorn – in April or May before they produce blossom or leaves – collect them together in small bundles and allow them to lie in the shade for two, three or four weeks until they are fairly well dried out.
Then have some wooden mallets, and with them pound these thorns on a hard piece of wood until you completely peel off the bark, which you immediately put in a barrel full of water. When you have filled two, three, four or five barrels with bark and water, allow them to stand like this for eight days until the water has drawn off all the sap of the bark. Then put this water into a very clean pot or into a cauldron, place it on the fire and heat it. From time to time, put some of this bark into the pot so that, if there is any sap left in it, it can be boiled out, and, when you have heated it for a little, take it out and put in some more.
This done, boil down what remains of the water, to a third of the original quantity, pour it from this pot into a smaller one and continue to heat it until it becomes black and begins to thicken, taking particular care that you do not add any water except that which was mixed with the sap. When you see it become thick, add a third part of pure wine, put it in two or three new pots and continue to heat it until you see that it develops a kind of skin at the top.
Then left these pots off the fire and put them in the sun until the black ink resolves itself from the red dregs. Afterwards, take some small, carefully sewn, parchment bags like bladders, pour the pure ink into them and hang them up in the sun until it is completely dried. When it is dried, take from it as much as you want, mix it with wine over a fire, add a little iron vitriol and write. If, as a result of carelessness, the ink is not black enough, take a piece of iron, an inch thick, put it on the fire until it is red hot and then throw it into the ink.
This translation is from Theophilus: The Various Arts, edited by C.R. Dodwell in 1961. Another translation was made in 1963 – Theophilus: On Divers Arts, by J.G. Hawthorne, and C.S. Smith.
You can find more recipes on making medieval ink from this guide created by Yale University Library