papyrus

Ingredients

nut-galls

Preparation Steps

Original Recipe Text

A leaf of papyrus is steeped in an infusion of nut-galls (p. 24).

Evidence

"The fraud may be detected using a leaf of papyrus, which has been steeped in an infusion of nut-galls: it immediately turns black when adulterated verdigris is applied (Secundus)."

Remarks

This represents the first historical record of the specific chemistry of iron gall ink: the reaction of gall-extracted tannic acid with iron sulfate (p. 24).