Cochineal
Dyeing with Cochineal
Cochineal grains are actually dried scale insects that are harvested from prickly pear cactuses. They produce one of the most brilliant and color-fast of the natural red dyes. Shepherd Textiles Cochineal is a top-grade Peruvian cochineal chosen for its high carminic acid content (24% by weight, vs. 17% in standard grades of cochineal). It can produce vivid reds, purples, and pinks on all natural fibers, including wool, cotton, alpaca, and silk. Check out this guide for tips on getting the best color from cochineal.
1. Background on Cochineal
The cochineal or grana is a scale insect (dactylopius coccus) that lives out its life on cactus pads. The female produces a bright red substance called carminic acid to discourage predation. Carminic acid also happens to be an excellent textile dye that produces color-fast, light-fast reds and purples. The cultivation of cochineal for this purpose dates to the pre-Hispanic era in Mexico. In Nahua the insect was called nocheztli, which means blood-of-the-cactus (see Bassett and Peterson 2012:48). It was a common tribute item sent by the rural provinces to the capital, and Europeans first encountered it in the 16th century in the grand markets of Tenochtitlan.
Cochineal, along with silver and logwood, quickly became one of the most lucrative exports of New Spain. Cochineal displaced all the older red dyes in Europe, especially after it was discovered that it gives true scarlet with a tin mordant (Donkin 1977:6-11). Cochineal is brighter than kermes and lac, and much less finicky to work with than raw madder root. The Spanish prohibited export of the live insects and maintained a monopoly on cochineal until the beginning of the 19th century. After the Mexican Revolution a few bugs were smuggled out to Spain’s Canary Islands, but the industry there collapsed when synthetic red dyes were invented just a few decades later. However, cochineal extract, also known as carmine, is still an important commodity today because it remains the best source of natural red. It is widely used in the food industry to gives candies and soft drinks their signature red color.
2. Safety Precautions
DO NOT INGEST. Cochineal is sold for textile dyeing, not as a food colorant.
Avoid eye contact. If eye contact occurs, rinse with cool water.
Not for use as a cosmetic additive; do not apply directly to skin or hair.
Open carefully to avoid spills. If a spill occurs, quickly wipe up with a paper towel or rag.
Cochineal can permanently dye clothing, countertops, rugs, utensils, or other property. Avoid contact with anything that is not meant to be dyed.
Use only dye pots and utensils dedicated to dyeing. Do not use any pots, containers, spoons, tongs, thermometers, or other utensils that will be used for food preparation..
Cochineal, metal mordants, and all dye baths and mordant liquors made while dyeing, should be kept out of reach of children and pets. Use only with adult supervision.
Shepherd Textiles, LLC is not liable for any misuse of this product or any unintended staining of your clothing, workspace, or other property. Use only as directed.
3. Recommended Supplies
Dye pot. Use a dye pot large enough to hold all your fibers, with plenty of room for them to move around and for the liquid to circulate freely. The best choice for cochineal is a large stainless steel stock pot or a pot with a non-stick surface.
Metal tongs. A pair of tongs is useful for stirring and taking fabric out. Use tongs dedicated to dyeing, and not for food preparation.
Rubber gloves. Wear rubber gloves while handling mordanted/dyed fiber before it is rinsed.
Candy thermometer. A cheap candy thermometer that clips to the side of the dye pot will make it easier to track the temperature.
Scale. Use a scale to weigh out fiber, mordant, and cochineal.
Alum mordant. The alum usually used for mordanting is aluminum potassium sulfate, also known as potash alum. It is the same alum that you can find in a jar in the spice section at the grocery store.
Cream of tartar. Shifts color to red and improves dye uptake.
PH strips (optional). For adjusting the dye bath PH.
Tea bags or a coffee filter. For straining the dye bath.
PH strips and a candy thermometer make it easier to control the dye bath.
4. Preparation I: Mordanting
Cochineal binds most strongly to fibers that have been pre-mordanted. The easiest mordant to work with is alum, which is used in baking powder and can be found in the spice section in most supermarkets. For best results, soak your fibers in water for a few hours before mordanting, so that the mordant will penetrate deeply and evenly. Make sure to weigh the fibers first, while they are still dry.
Alum will dissolve quickly into hot tap water.
Heat fibers for an hour at 180F, then allow to cool.
For protein fibers (wool, silk, alpaca): Mordant at 12% WOF with alum.
Weigh out the fibers you plan to dye (while they are dry). Multiply that weight by 0.12 to get the amount of alum you will need.
Fill your dye pot with hot tap water, leaving enough room for the fiber.
Weigh out the correct amount of alum and pour it into the dye pot. Mix with a spoon or metal tongs until all powder has dissolved.
Gently place your wetted fibers into the mordanting solution.
Heat mordant bath to 180F and maintain heat for 1 hour. If you don’t have a candy thermometer, you will have to estimate the temperature. At 180F, steam vapor will be rising off the water but it will not be bubbling. If your mordant bath starts to bubble, turn down the heat.
Stir every 15 or 20 minutes to make sure fibers mordant evenly. If they do not, the dye will take better in some places than others.
After an hour, remove from heat and let cool to room temperature. Once cool, you can immediately proceed to rinsing, or you can leave the fibers to steep overnight in the mordant bath. This will improve results, especially when dyeing thick or tightly woven fabrics.
Remove cooled fibers. Wearing rubber gloves, gently squeeze excess mordant solution back into the pot. Rinse well in lukewarm water. The fiber does not need to be washed with detergent, but any unbonded mordant should be rinsed out. Set aside until ready to dye. Keep out of reach of children and pets.
Dispose of mordant solution according to local guidelines.
For cellulose fibers (cotton, linen, etc.): Scour and pre-treat with a tannin for best results.
Cellulose fibers like cotton are more resistant to natural dyes and mordants than protein fibers like wool. They benefit from being pre-treated with a tannin, which will make the fibers accept mordants and dyes more easily. The colors will also be deeper and more light-fast.
Scour cellulose fibers well. Traditionally this is done in a highly alkaline soda ash solution. Add 2 tsp of soda ash and 1 drop of dish soap to a 5-gallon dye pot. Add cellulose fibers and heat to 180F-190F for an hour, stirring occasionally. Remove from heat, and when cool enough to handle, rinse and wring out well. Household detergents like Tide© are also alkaline (PH 11), so you can also toss the fiber in a washing machine on a high-temperature cycle with plenty of detergent. This will not clean them nearly as deeply as simmering with soda ash, but it will yield much better results than not scouring at all.
Apply a clear tannin like Sumac Extract to the fiber. To use, fill your dye pot with hot water, dissolve 5% WOF of your chosen tannin in the dye bath (check vendor’s instructions—each will need a slightly different WOF) and simmer for an hour. Be very careful to keep the fiber moving around: some tannins have insoluble particles that love to get stuck in fabric, and they can cause splotches later on in the dyeing process. After an hour, let cool. If time permits, steep overnight—this will greatly improve final results. When finished, remove fibers and rinse well.
Mordant as described above for protein fibers.
The Recipes.
5. Recipe - Natural Fuchsia
Cochineal’s natural dye color, at neutral PH and without any modifiers, is an intense fuchsia or purple-pink. For best results, use fiber that has been pre-mordanted with alum. To get deep colors on cotton, pre-treat with a tannin before mordanting. The swatches shown below use 5% weight-of-fabric (WOF) cochineal; for a dark fuchsia verging on purple, use 8-10% weight-of-fabric.
Fill your dye pot with warm water, making sure there is enough room for the fabric to move around and for water to circulate freely.
Adjust the PH to 7 (neutral) with white vinegar or baking soda. If you don’t have PH strips, just leave it as is; most tap water is neutral, or close to it.
Weigh out 5% weight-of-fabric (WOF) ground cochineal (multiply the dry weight of the fabric by 0.05 to get the correct amount of extract). Make the dye bath: you can (1) put the cochineal into a tea bag, tie it off, and simmer at 180F for two hours, or (2) simmer the ground cochineal in a your dye pot for 2 hours, allow to cool, and then strain through a coffee filter to get out all the grains. If you use a tea bag, remove it before adding the fiber; if it brushes up against the fiber in the pot, it can leave a dark splotch.
Add your pre-mordanted, pre-soaked fibers to the dyebath.
Raise the temperature to 180F and maintain for 2 hours, stirring every 20 minutes or so to make sure everything dyes evenly.
After 2 hours, remove pot from heat and allow to cool to room temperature. For best results, cover and let the fibers steep overnight.
Remove the fibers and rinse briefly in lukewarm water to remove any particles of dye. You can either proceed immediately to rinsing with detergent, or hang the fabric up to dry first to help the color set. Make sure to hang it up somewhere where dripping dye will cause no damage.
For final rinsing, use a PH-neutral detergent like Synthrapol that is designed to wash out loose dye. Follow the manufacturer’s directions for best results. Avoid commercial laundry detergents: even mildly basic detergents with a PH of 8 or 9 can shift the color of the dyed fabric while it is being rinsed. CAUTION: Cochineal will bleed if not thoroughly rinsed out after dyeing.
Hang up to dry.
NOTE: Softer colors of red and pink can be achieved by using smaller percentages of Cochineal Extract.
6. Recipe - Cherry Red
Cream of tartar has a natural affinity for cochineal, and adding it to the dyebath will shift the color toward cherry red. It also improves dye uptake and makes it easier to get deep, rich colors. Cream of tartar is acidic and shifts the dyebath to PH 4 or 5. Be careful when rinsing not to use an alkaline detergent—even a mildly basic soap with a PH of 8 or 9 can shift the color of the dyed fabric back toward purple or pink.
Fill your dye pot with warm water, making sure there is enough room for the fabric to move around and for water to circulate freely.
Adjust the PH to 5 with cream of tartar. If you don’t have PH strips, add two teaspoons to approximate a slightly acidic dye bath.
Weigh out 5% weight-of-fabric (WOF) ground cochineal (multiply the dry weight of the fabric by 0.05 to get the correct amount of extract). Make the dye bath: you can (1) put the cochineal into a tea bag, tie it off, and simmer at 180F for two hours, or (2) simmer the ground cochineal in a your dye pot for 2 hours, allow to cool, and then strain through a coffee filter to get out all the grains. If you use a tea bag, remove it before adding the fiber; if it brushes up against the fiber in the pot, it can leave a dark splotch.
Add your pre-mordanted fibers to the dyebath.
Raise the temperature to 180F and maintain for 1.5-2 hours, stirring every 20 minutes or so to make sure everything dyes evenly.
After 1.5 or 2 hours, remove pot from heat and allow to cool to room temperature.
Remove the fibers and hang up to dry to help the color set. Make sure to hang it up somewhere where dripping dye will cause no damage. We recommend not rinsing the fiber until the color has set, because if your tap water is on the high side of neutral (PH 7 or 8), it can cause the color to shift from red back toward fuchsia.
For final rinsing, use a PH-neutral detergent like Synthrapol that is designed to wash out loose dye. Follow the manufacturer’s directions for best results. Avoid commercial laundry detergents: even mildly basic detergents with a PH of 8 or 9 will shift the color of the dyed fabric while it is being rinsed. CAUTION: Cochineal will bleed if not thoroughly rinsed out after dyeing.
Hang up to dry.
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