Name: Judy

Message: I'm a beginner and I'm using plant dyes before I get into the more "advanced" materials. I successfully used annato seeds with alum and ferrous sulfate. With the abundance of annato here in the philippines, I was wondering, is there a way I could make a powdered annato dye that I could store in a bottle? I tried cooking the dyebath until it dried and I scraped the material that clung to the pot bottom, but when I added the powder to water, it just floated and didnt mix. Is homemade powdered dye possible to make? Thank you. 

What you're doing IS more advanced dyeing, in my opinion. I would call the best types of synthetic dyes more suitable for beginners, since they are much easier to use satisfactorily; natural dyeing is more advanced, because it takes so much more skill to get good results with it!

Are you using either soda ash or potash (sodium carbonate or potassium carbonate) in your dyebath? Old recipes for dyeing with annatto call for these chemicals for helping to dissolve annatto in a dyebath. Please test to see whether your annatto extract powder will dissolve more easily in water to which you have added about one tablespoon of sodium carbonate per gallon. If you don't know about soda ash, see if you can buy washing soda that is free of dyes, perfumes, and other additives; it contains sodium carbonate, too, though in a slightly different form. Sodium carbonate is usually available at swimming pool supply houses for use in raising the pH of the water. Avoid sodium bicarbonate, which is not alkaline enough for your purposes. Lye (sodium hydroxide) would also work, in smaller quantities, but it is much more dangerous to use.

The coloring in the waxing coating of annatto seeds is a carotenoid, bixin, closely related chemically to the far more expensive coloring principle of saffron. Like saffron and turmeric, it is extremely sensitive to fading caused by light; the energy absorbed by the dye from visible light breaks apart the dye molecule. Textiles dyed with annatto should be dried indoors after washing (not in the sunlight), stored in a dark place, and redyed every year or two as needed, when the color has faded too much. Here is a drawing depicting its chemical structure:


Your problem with the annatto extract is that it is hydrophobic, or oil-loving. Most substances are either hydrophobic, which means that they will dissolve better in oil than in water, or hydrophilic, which means that they dissolve better in water than in oil. Annatto is often used in cooking to provide a yellow color; a typical use is to grind the annatto seeds in a coffee grinder, then cook the powder in oil with other spices. If you cook annatto in a mixture of oil and water, you will see that the coloring principle, bixin, moves into the oil more than it does in the water. The same is true of the red pigment in tomatoes.

Unfortunately, it is impractical to apply a dyestuff to fabric when it is dissolved in vegetable oil instead of water. Imagine the mess! Some less oily solvents that would work well, such as chloroform, are too toxic for you to use. The chemical as first extracted from the seeds is in the form cis-bixin, which can also be dissolved in methanol (wood alcohol or methylated spirits) or acetone (fingernail polish remover). I think it would be easy to add annatto dissolved in methanol to your dyebath, since methanol is easily dissolved in water, but I'm not sure how much of the annatto would remain dissolved in the dyebath after you add it, and of course, as you heat the dyebath, the methanol would boil off at a lower temperature than water, exposing you to possibly dangerous (and flammable) fumes.

In the food industry, bixin is converted to an oleoresin by extracting annatto seeds with ethyl acetate, then treating this extract with sodium hydroxide (lye or caustic soda) or potassium hydroxide (caustic potash) with heat and pressure. This converts the bixin into the sodium or potassium salt, norbixin, which is soluble in water and commonly used as a food additive. It might be possible to adapt this process for use at home, but I don't think that you will want to. It's important to note that norbixin is not water-soluble in the presence of acid, such as vinegar.

One answer to relatively insoluble natural dyestuffs is to place the ground-up dyestuff into a small bag that you can make of a fine-mesh fabric and tie or sew closed, and cook this "teabag" with your fabric in the water. A little of the dye will dissolve in the water, then leave the water to color the properly-prepared fabric; as you boil the fabric with the dyestuff, with time, more and more dye leaves the dyestuff in the bag and colors the fabric. Be sure to use soda ash or another high-pH chemical with this method.

Another very good possibility is that you might store a concentrated liquid made from your annatto dyebath, instead of boiling it all the way down to dryness. Glass jars are the best for storage, but many plastics are fine, too. The kind of very thin gallon-sized plastic jugs we use in the US for milk are too thin to be a good choice for storage, as they inevitably will develop a leak, if you keep them too long, and spill their contents. Thicker plastic buckets or jars should be fine.

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