iron-polyphenol complex

Ingredients

gallnuts (Quercus infectoria), water, gum arabic, green vitriol (FeSO4)

Preparation Steps

Original Recipe Text

QI.2 Another midād: Take the quantity you desire of gallnuts and grind them as if they were chickpeas; add ten times the same amount of water and put it on a low fire until it becomes two parts; then let it cool and clarify, and add for each part one and a half part of gum and enough green vitriol, then use it. (p. 7). Experimental reproduction used 3.5 g of gall nuts ground until they were the size of chickpeas. Ten times water (35 mL) was added, heated to 60 °C, and evaporated by 1/3. 5.25 g of gum arabic and 2.78 g of iron sulfate were added after filtration. (p. 11).

Evidence

"For the first time, this paper systematises the medieval preparation of black writing inks found in the important thirteenth century Andalusian technical treatise written by Muhammad ibn Idrīs ibn al-Qalalūsī (1210–1308)."

Remarks

The term midād is used generically for black writing inks in the Al-Andalus context for the period (p. 3). The study found that water-only extractions yield lower concentrations of phenolics compared to recipes using wine or vinegar (p. 11). Gallic acid was found to be a minor compound in the gall extracts, whereas pentagalloylglucose and hexagalloylglucose were the major compounds (p. 1).