Fe3+-polyphenol dark complexes

Ingredients

Quebrantar Ground galls, Water, Asiche (FeSO4), Gum arabic, Pomegranate peel

Preparation Steps

Original Recipe Text

The Cordoba recipe (Table 1, p. 3) calls for Quebrantar Ground galls in water (26.07 mL per 1 g galls) with the specific additive of pomegranate peel (0.5 mass ratio). The iron salt used is 'Asiche' (FeSO4). The ratio of Galls:FeSO4:Gum is 1:1:0.5. The process involves an 8-day extraction at room temperature, followed by boiling and filtration (p. 3).

Evidence

"Cordoba | Quebrantar Ground | Water | Asiche | 1:1:0.5 | Pomegranate peel (0.5) | 8 days RT, Boil | Yes"

Remarks

Cordoba is distinct as it is the only ink where gallic acid is the major phenolic compound, rather than polygalloyl esters of glucose (p. 8). It showed the lowest extraction yield of phenolic compounds (7±4 mg/mL) (p. 8). Pomegranate peel contributes punicalin, punicalagin, and ellagic acid, which react with iron (p. 6). This ink also displayed the highest pH value (approx. 2.1) among the tested samples (p. 8).