Acorn & Iron Grey

Tannin-rich acorns plus a splash of iron — a foraged grey-black.

Color

Soft warm grey to inky black

Binder

Gum arabic + honey

Boil crushed acorns for tannin, then drop in iron-vinegar to turn it black.

▸Acorns are full of the same tannin as oak galls.
▸Tannin + iron is the same chemistry behind 1,000-year-old document inks.
▸Most permanent foraged black there is.

Steps

01
Simmer crushed acorns in water 1 hour to extract tannin; strain.
02
Reduce to a syrup.
03
Add iron-vinegar drop by drop — the liquid darkens instantly.
04
Stir in gum arabic and honey; pan up.

Materials

— A handful of crushed acorns (caps included)
— 500 ml water
— A few drops of iron-vinegar (steel wool soaked in vinegar 1+ week)
— 1 tsp gum arabic + drop of honey

Safety

High Risk

Involves caustics, acids, or open flame. Full PPE and trained supervision recommended.

Hazards identified

Acidic / corrosive etchant
Airborne dust — respiratory irritant

Quick checklist

☐Wear goggles, apron, and acid-resistant gloves
☐Always pour acid into water, not the reverse
☐Neutralize and dispose per local hazardous-waste rules
☐Wear an N95 / FFP2 mask when handling dry powders
☐Mix in a tray to contain dust; wipe surfaces wet
☐Work in a ventilated area; keep food and drink out of the studio
☐Read each material's safety data sheet (SDS) before starting
☐Have water, soap, and a first-aid kit accessible

Heuristic guidance derived from listed materials. Always consult each material's safety data sheet (SDS) and a qualified instructor before attempting.

Notes

Same chemistry as oak-gall ink. Fully lightfast and the easiest foraged black.