How kava makes colour
Three pieces of chemistry explain almost everything you will see in the pot.
The visible pigment is a group of flavonoids called flavokawains. They are chalcones, the same broad family that colours onion skins, weld and turmeric, and they absorb light near 340 nanometres, which the eye reads as a clear lemon-to-amber yellow. Riding alongside them in the root's resin are the kavalactones. Most are close to colourless, but the two with extended double bonds, yangonin and desmethoxyyangonin, carry their own pale yellow and add to the depth.
The browns are made by time. Exposed to air, kava's polyphenols oxidise and polymerise into larger, water-insoluble pigments, much as a cut apple tans. This is why kava stains so tenaciously and why older, sappier or above-ground material reads darker.
Two facts shape how you handle it. First, as a flavonoid colourant kava behaves like other plant yellows: it brightens and holds far better when bonded to an aluminium mordant, and it can be precipitated into a solid lake pigment. Second, kava is low in tannin. Where a recipe leans on tannin chemistry, most visibly the deep blacks of an iron reaction, kava supplies little of its own and borrows it from the material instead. That single fact decides a lot of what follows.
The colour range
From the root itself the honest span is narrow and warm: pale gold, through amber, into chestnut brown. The cultivar moves you along that one line rather than into new hues. What sets the depth is pigment load, so a pale, lightly pigmented kava gives soft gold while a heavily pigmented cultivar such as the red-stemmed Bir Kar grinds almost chocolate-brown and gives the darkest bath.
The genuinely different colours are applied, not grown. Iron saddens the yellows toward olive, khaki and grey. Alkalinity warms and deepens them toward amber and orange-brown, because chalcones respond to pH. Between cultivar choice, iron and pH you can reach every band in the strip above.
The plant is far more colourful than its powder. Red-stemmed cultivars carry anthocyanins, the same red-purple pigments as blackcurrants, but those live in the stems and skin, not the root. Dried kava is the clean inner root, so almost none of that colour reaches the bath. The reds are real, they simply sit in the parts left out of the powder. To reach them you have to go above ground, which is the next section.
Beyond the root: the aerial parts
Everything above uses the root, the part sold as powder and the part used in the traditional preparation. The rest of the plant is normally set aside, yet it holds the colours the root cannot give.
For a dyer that makes the stems, leaves and peelings worth knowing, because between them they cover the cool end of the spectrum that the root simply does not reach. Three parts, three different pigments.
The aerial palette, roughly: pinks and purples from the stems, greens from the leaves, a stronger yellow from the peelings.
Stems and skin → reds and purples
The red-purple of a kava stem is anthocyanin, the same pigment family as red cabbage and blackcurrant, and red-stemmed cultivars such as Bir Kar carry the most. Anthocyanins are pH indicators by nature, so the same extract swings colour with what you add to it: red in acid (a splash of vinegar), violet to blue near neutral, and toward green in alkali (soda ash). One stem brew can give you several hues. The catch is that anthocyanins are fugitive, unstable in light and especially in alkali, so treat these as vivid but short-lived. They suit paper, eggs and quick decorative work far better than anything you want to keep for years.
Leaves → greens
The leaves bring chlorophyll, the one route to true green on the whole plant, usually landing as a soft yellow-green or olive once it mixes with the flavokawains also present in the foliage. Chlorophyll is not especially lightfast either, so again this is colour for the moment rather than the heirloom.
Peelings and bark → a stronger yellow
The outer peelings and stem bark concentrate more flavokawains than the clean inner root, so they give the deepest, most saturated yellow the plant offers. If you want the boldest gold rather than a soft one, this is the part to brew.
There is a reason the aerial parts are kept out of traditional preparations. Leaves and stem peelings are reported to concentrate compounds such as pipermethystine and flavokawain B that have been linked to liver toxicity, which is why those parts are not consumed. For colour work on surfaces this is not a handling hazard, but it sets firm limits: never use aerial-part material or its dye baths on anything that touches food or skin, never ingest it, wear gloves, and keep your tools separate. The upside is real, though. Dyeing puts a normally discarded, non-consumable part of the harvest to good use.
One practical note on sourcing. Because shops sell pure root powder, working with aerial parts means access to a fresh plant or a grower's trimmings. If you grow kava yourself, the prunings are your palette.
The small kit
Everything below draws on the same short shelf of materials. Assemble these once and you can work across every surface in this guide.
Kava or makas
The colourant. Cheap traditional grind works, and so does the spent root fibre (makas) left after kava has been strained. More powder and longer steeping mean a deeper bath.
Alum
Potassium aluminium sulfate, sold for pickling and dyeing. The mordant that brightens and fixes the yellow, and the base for making a lake pigment.
Soda ash
Scours fibre, raises pH to warm the colour, and precipitates pigment out of solution. Washing soda is a workable stand-in.
Iron water
Steel wool or rusty nails left a week in water with a splash of vinegar. A few brushfuls shift kava toward grey and, on tannic materials, toward black.
White vinegar
Mildly acidifies a bath or rinse to keep colours bright and warm, and helps set surface stains.
Gum arabic
Tree sap that thickens and binds. Turns a strong kava brew into a usable ink and helps it sit on paper.
Keep a dedicated pot, spoon and jars for colour work and never return them to the kitchen. Wear gloves, work in a ventilated space, and always test on an offcut first. Iron water in particular stains skin, sinks and benchtops.
Textiles
Cloth is the natural home for a flavonoid dye. Animal fibres (silk and wool) take it most readily; plant fibres (cotton and linen) need a little more coaxing but reward it.
Vat dyeing
- Scour. Simmer the fabric an hour in water with a couple of teaspoons of soda ash and a drop of detergent to strip oils, then rinse.
- Mordant. Soak the wet cloth several hours in warm water with alum at about a tenth of the dry fabric weight and a pinch of soda ash.
- Dye. Simmer kava in plenty of water for an hour, strain, then add the cloth and hold at a low simmer for an hour. Switch off and let it cool in the bath, ideally overnight, where most of the bond forms.
- Modify and wash. Dip in iron water for olive and grey, or add soda ash for warmth, then rinse cool and dry in shade.
Eco-printing
Kava also works as a background colour in contact printing. Lay leaves between cloth, place a kava-soaked carrier cloth over them to lay down a golden ground, and add an iron-soaked carrier cloth where you want the leaf prints to darken and sharpen. Roll the layers tight, bind, and steam for around half an hour. The technique, popularised by India Flint, lets kava tint the field while pressed plants supply the pattern.
Resist and shibori
Fold, clamp or bind the cloth before dyeing to hold pattern. Kava's quiet palette suits soft, low-contrast resist particularly well, giving the worn, tea-stained look rather than a hard graphic edge.
Wood
Raw wood drinks up a water-based stain, and a strong kava brew behaves much like the well-known tea and coffee wood stains, soaking in to leave a warm, penetrating brown rather than a film on the surface.
- Brew strong. Make kava three or four times the strength of a normal brew, and strain it clear.
- Sand and wet. Sand the timber, then wipe with a damp cloth to raise the grain and help the stain penetrate evenly.
- Build coats. Brush on thin, even coats, letting each dry before the next. Two or three coats deepen the tone considerably.
- Seal. Finish with an oil or wax to protect the colour and even the sheen.
Brushing iron water over a tannin-rich wood like oak triggers a chemical reaction that turns it grey to black, the traditional ebonising trick. Because kava carries little tannin of its own, it cannot blacken a low-tannin wood by itself, but a kava coat first adds warmth and a little tannin to the surface, then iron water over the top pulls it toward a deep, weathered grey-brown. This is a reaction rather than a coating, so it tends to be unusually durable.
Paper
For an aged, parchment look, brush a strong kava brew across the sheet or dip it whole. Crumpling the paper first traps darker colour in the creases for a mottled, antique finish. Dry it flat, pressing under a warm iron through a cloth if you want to set the tone and flatten the cockle. A soy-milk pre-soak gives the colour more to grip and a deeper hold. The result suits journaling, labels, bookbinding and wrapping. Treat it as decorative, since paper stains of this kind are not lightfast.
Inks and pigments
Botanical ink
Simmer a strong kava brew down until it concentrates, then whisk in a small amount of gum arabic while it is still warm to bind it and help it flow. A drop of clove or thyme oil keeps it from spoiling. As brewed it writes a warm gold-brown; a touch of iron water shifts it to a grey sepia. Bottle it and use with a dip pen or brush.
Lake pigment
A lake pigment is a water-soluble dye locked onto a mineral base so it becomes an insoluble, grindable solid, the route from dye to paint. The method is the same one used for weld and other plant yellows:
- Extract. Simmer kava, then strain to a clear, strong liquor.
- Add alum. Stir dissolved alum into the warm dye so it binds to the pigment.
- Precipitate. Slowly add soda ash. The pH rises, the mixture fizzes, and the pigment drops out as a soft sludge.
- Rinse and dry. Let it settle, pour off the clear water, rinse, then dry the paste and grind it to a powder. Bound with gum arabic it becomes watercolour; with oil, a paint.
Noble kava is lightly pigmented, so expect a modest yield of a soft, earthy yellow rather than a vivid one. A more deeply coloured cultivar gives more.
Leather
Vegetable-tanned leather is effectively raw, untreated hide and takes a natural colourant well. Clean the surface, then wipe on a strong kava brew in thin coats with a soft cloth in small circular strokes, letting each coat dry fully before the next to keep the colour even. Finish with a leather conditioner to feed the hide and lift the depth.
Vegetable-tanned leather is itself loaded with tannin from the tanning process. That means iron water reacts with the leather directly and blackens it dramatically, no kava required, while a kava coat underneath warms the result. It is the same iron-and-tannin chemistry as ebonising wood, simply working with the tannin already in the hide.
More to try
The same bath colours plenty of smaller things. A kava dip gives eggshells a rich umber, deepest over brown eggs (decorative or blown eggs, not for eating), in the old tradition of dyeing eggs with onion skin and coffee. Gourds, wooden beads, raffia and basketry fibre all take an earthy tone from a soak. And a quick kava wash is a tidy way to age and distress new cotton, fresh paper or pale wood for props and crafts. None of these are food or cosmetic uses; this is colour for objects and surfaces only.
Honest limits
Natural colour asks for different expectations than a synthetic packet. Flavonoid yellows have moderate lightfastness and will gently fade and mellow with sun and washing; the brown oxidised pigment is more stable, and a proper alum mordant or an iron reaction improves durability markedly. Anything relying on surface staining alone, on paper especially, should be kept out of direct light.
Results shift with cultivar, freshness and how far the material has oxidised, so two batches will rarely match exactly. That variability is part of the character rather than a fault. Test every recipe on an offcut before committing a finished piece, and remember that kava's low tannin makes its iron reactions gentle unless the material brings tannin of its own.
Who makes this
This guide is put together by a small team with a long-standing interest in the plants of the Pacific and the uses of them that get overlooked. Kava is a genuinely fascinating plant with a rich range of cultural uses across its home region, and colouring is one of the lesser-known ones, well understood in the Pacific yet barely documented anywhere else. That gap is the reason for this guide: to gather what is known about dyeing and pigment-making with kava, test it, check it against the chemistry, and set it out plainly in one place. We are also working towards a European textile and lifestyle brand built around traditional Pacific plants and botanicals, and this research grew alongside it.
We are based in Paris and keep adding to the guide as we try more. Notes, corrections and photographs of your own results are always welcome.
Further reading
- Lake pigments from plant dyes — Ecology of Color, Botanical Colors
- Aluminium dye lakes from plant extracts — Dyes and Pigments
- Ebonising wood with tannin and iron — Maker Design Lab, Timber Biscuit Woodworks
- Making botanical inks — Tinctorium Studio
- Dyeing vegetable-tanned leather — Tannins.org, PMC
- Eco-printing and iron blankets — Botanical Colors
- Staining paper with natural dyes — The Carle Museum
- Kava pigments and colour — Colorimetric assessment of kava quality, the flavokawains
- Kava as a Pacific barkcloth colourant — Polynesian Tapa Colourants, npj Heritage Science