Dyeing Gold with Onion Skins — The Most Accessible Natural Dye in Any Kitchen

Gather the dry, papery outer skins of yellow onions. You need 100-200% WOF — for 100 g of wool, collect 100-200 g of skins. This sounds like a lot, but onion skins are very light and a large bag fills quickly. Collect over several weeks of cooking, or ask a greengrocer — they discard onion skins in bulk. Use only the dry, papery outer layers, not the moist fleshy layers beneath. The skins should be golden-brown and crisp. Avoid any that are mouldy or wet.

Place the onion skins in a dye pot and cover with 4 litres of warm water. Soak for at least one hour — overnight is even better. The skins will begin releasing quercetin immediately, turning the water a rich amber-gold. Unlike dense heartwood dyes, onion skins release colour quickly because they are thin and papery. Pressing them below the water surface helps ensure even extraction.

Bring the pot to a gentle simmer (80-85°C) and hold for 30-45 minutes. The liquid will deepen to a vivid dark amber. Stir occasionally. Onion skins extract faster than most plant dyes — 30 minutes is usually sufficient for full extraction. Over-simmering does not harm the colour, but there is little benefit past 45 minutes. The skins will lose their colour and turn pale tan when fully exhausted.

Strain the dye liquor through a fine mesh strainer into a clean pot. Press the skins to extract all the golden liquid. Onion skin fragments left in the dye bath can tangle in wool and cause uneven colouring. The strained liquid should be a clear, deep golden-amber — a beautiful and vivid dye bath.

Pre-wet the alum-mordanted wool in lukewarm water for 15 minutes, squeeze gently, and lower it into the onion skin dye bath at room temperature. Slowly raise the temperature to 80°C over 15 minutes, then hold for 45 minutes. Turn the wool gently every 10 minutes to ensure even uptake. The wool will absorb colour quickly — a warm, clear golden-yellow that deepens with time. The alum mordant forms a stable complex with quercetin, giving the best lightfastness and the brightest gold.

Turn off the heat and let the wool cool in the dye bath overnight for deepest colour. Remove, squeeze gently, and rinse in lukewarm water until the runoff is mostly clear. The final colour is a warm, glowing gold — ranging from pale buttercup at low concentrations to deep burnt orange at high concentrations. Onion skin gold fades gradually in direct sunlight over months but holds well for indoor textiles and garments. Dry in shade.