Dyeing Scarlet with Kermes — Europe's Original Crimson Insect Dye

Use 20-30% WOF of dried kermes insects for a deep scarlet. For 100 g of wool, weigh out 20-30 g of dried kermes. The insects are sold as small, hard, reddish-brown granules — they look like tiny dried berries or seeds, each one a desiccated female insect body. Kermes is expensive and difficult to source — it is still hand-harvested from wild kermes oaks in the Mediterranean, primarily in Morocco, Spain, and Greece. Each insect yields far less dye than a cochineal insect of similar size.

Grind the dried kermes insects in a mortar and pestle until reduced to a fine powder. Kermes insects are harder than cochineal and require more force to grind — the shells are tough and resist crushing. The powder will be a dark reddish-brown, less intensely coloured than ground cochineal. Thorough grinding is essential because kermesic acid is locked inside the insect's body and releases slowly from large fragments.

Place the ground kermes in a glass jar with 500 ml of warm water. Stir, cover, and let it stand overnight (8-12 hours). The kermesic acid dissolves slowly — the overnight soak extracts significantly more pigment than adding the powder directly to the dye pot. The liquid will turn a deep red, though less opaque than a cochineal extract of similar concentration.

Fill the dye pot with 4 litres of water. Add the entire kermes extract — liquid and sediment — and stir thoroughly. Add 6 g of cream of tartar to create a mildly acidic bath, which brightens the scarlet and improves colour uptake. Stir until dissolved. The bath will be a warm, glowing red — less vivid than cochineal at the same concentration, but with a distinctive warmth that kermes dyers prize.

Pre-wet the alum-mordanted wool, squeeze out excess, and lower it into the dye bath at room temperature. Slowly raise the temperature to 85°C over 30 minutes, then hold at 80-85°C for a full 60 minutes. Turn the wool gently every 10 minutes. Kermes requires patient, slow dyeing — the kermesic acid molecules penetrate wool fibres more slowly than cochineal's carminic acid. The bath will pale gradually as the pigment transfers to the wool.

Turn off the heat and let the wool cool in the dye bath overnight. The overnight rest deepens the colour noticeably. Remove the wool the next day, squeeze gently, and rinse in lukewarm water until the runoff is mostly clear. The final colour is a warm, luminous scarlet-red — slightly more orange than cochineal crimson, with a glow that ancient dyers described as the colour of fire. Kermes red has excellent lightfastness and washfastness, rivalling cochineal. Dry in shade.

If you have also dyed with cochineal, place the two skeins side by side. Cochineal crimson leans blue-red (cool); kermes scarlet leans orange-red (warm). Cochineal is more saturated per gram of insect. This comparison explains why cochineal swept kermes from European dyeing in the 16th century — the New World insect was cheaper, stronger, and more versatile. But the side-by-side also shows what was lost: kermes has a warmth and luminosity that cochineal does not replicate. Medieval paintings of scarlet robes show kermes red, not cochineal red — a distinction that matters to art historians, textile conservators, and natural dyers preserving the old techniques.