What is the difference between alum sulfate and aluminum acetate as mordants, and why does it matter for Patreon documentation?

Alum sulfate (potassium aluminum sulfate, KAl(SO4)2·12H2O) and aluminum acetate (Al(C2H3O2)3) both fix dyes to fiber via aluminum cation coordination with dye molecules and fiber functional groups, but they behave differently at the pH level in ways that produce distinct color outcomes on protein and cellulose fibers. Alum sulfate dissociates in water to produce a mildly acidic solution (pH 3.5–4.5 at typical mordant concentrations of 10–20% WOF — weight of fiber). This pH range is ideal for protein fibers (wool, silk) because the acid environment promotes hydrogen bonding between the fiber and the mordant-dye complex without damaging the protein structure. On cellulose fibers (cotton, linen, hemp), alum sulfate produces less durable results because the acid solution does not promote the ionic bonding that cellulose requires for mordant fixation; cellulose fiber mordanted with alum sulfate typically shows 40–60% of the depth of shade achievable on protein fiber from the same dye bath. Aluminum acetate at the same WOF percentage produces a higher solution pH (pH 4.5–5.5) because the acetate ion is a weak base that partially buffers the acid. This higher pH range dramatically improves aluminum bonding to cellulose fiber — the aluminum cation coordinates with the cellulose hydroxyl groups more effectively above pH 4.5, producing color depth on cotton and linen that approaches the results achievable on wool. The practical implication for Patreon documentation: a dye bath record that specifies only 'alum mordant, 15% WOF' is not reproducible by a patron who is working with different fiber. The documentation must specify the mordant form (sulfate vs acetate), the WOF percentage, the solution pH measured with a pH meter or strip, the fiber type, and the mordant bath temperature and duration. Color depth on the finished fiber must be noted as a reference for reproducibility across mordant and fiber type combinations.

How should natural dyeing creators document iron modifier effects for Patreon patrons?

Iron modifier (ferrous sulfate, FeSO4·7H2O) used as an after-bath modifier or as a co-mordant shifts color in a way that differs fundamentally between saturation and hue depending on the dye class. The mechanism is iron coordination with the dye-mordant complex on the fiber: iron ions displace some aluminum ions and form a more stable but darker complex. With flavonoid dyes (weld, goldenrod, onion, osage orange), iron modification shifts the yellow or gold hue toward green and olive while simultaneously reducing brightness — the color becomes both darker and cooler in tone. At low iron concentrations (1–2% WOF), the shift is a slight greening and dulling of a yellow-alum result; at moderate concentrations (4–6% WOF), the shift produces a clear olive or bronze; at high concentrations (8–12% WOF), the result is dark greenish-brown or khaki. With tannin-rich dyes (black walnut, oak gall, sumac), iron produces dramatic darkening toward grey-black — this is the chemistry behind traditional iron-gall ink. With madder (alizarin and purpurin), iron modification shifts the red-orange hue toward a muted reddish-brown or terracotta, with a significant reduction in saturation. The saturation vs hue distinction matters for documentation: iron does not produce a simple darkening — it shifts hue in a direction specific to the dye class. A documentation note that records 'iron modifier' without recording the original dye class, the iron concentration as WOF percentage, and the hue shift direction is not useful to a patron trying to reproduce the result. The full documentation covers the pre-modification sample (dye class, mordant, color observed on fiber), iron concentration (WOF percentage), modifier bath pH (should be slightly acidic — pH 4.0–5.0 — to keep iron soluble; above pH 6.0 iron precipitates as ferric hydroxide and produces uneven results), modifier bath temperature (cool, 40–50°C, because high temperature and iron can damage protein fibers), duration (15–30 minutes), and the resulting hue and saturation comparison to the pre-modification sample. A side-by-side sample card — pre- and post-modification on the same fiber from the same dye bath — photographed in consistent lighting is the definitive Patreon deliverable for iron modifier documentation.

What dye plant phenology data should natural dyeing creators document for Patreon?

Dye plant phenology — the relationship between plant growth stage, harvest timing, and the resulting colorant yield and hue — is one of the most under-documented areas in natural dyeing because most available guides specify harvest timing in general terms ('harvest at full bloom') without documenting how color and yield change across the phenological window. A Patreon that documents the phenological spectrum across harvest stages is delivering calibration data that patrons who grow their own dye plants cannot get from any published source. Weld (Reseda luteola) is the highest-yielding yellow dye plant in temperate cultivation and demonstrates phenological color change clearly: harvested at the rosette stage (before the flower spike emerges, typically May–June in the UK), the leaves yield a greenish-yellow with high luteolin content and good washfastness; harvested at early spike emergence (spike visible but flowers not yet open), yield is at maximum with slightly warmer yellow hue; harvested at peak bloom (flowers fully open), yield drops 15–25% but hue shifts toward pure yellow; harvested after bloom but before seed set, yield drops further and hue becomes more muted gold. Document the harvest stage as a photograph alongside the color result on mordanted fiber rather than as a calendar date, because regional climate variation makes calendar dates non-transferable. For Japanese indigo (Persicaria tinctoria), phenology matters differently: the indigo precursor (indican) concentration in the leaf peaks before flowering, typically at the point when the plant has set multiple leaf pairs but the flower spike is not yet visible. After flowering begins, leaf indican concentration drops sharply — harvesting after flower spike emergence yields 30–50% less indigo than pre-flower harvest. The documentation for Japanese indigo should record the plant growth stage at harvest, the leaf color (deep blue-green indicates high indican; pale leaves indicate stress or early harvest), the fresh leaf weight, the extraction method, and the amount of indigo paste or dried indigo produced. This yield-to-plant-stage relationship is publishable Patreon content that no YouTube video can carry because the video shows one harvest stage; the Patreon archive shows the phenological range.

How do fructose and iron/lime indigo vats differ, and how should natural dyeing creators document each for Patreon?

Fructose vats and iron/lime (ferrous sulfate/slaked lime) vats are both reduction systems for synthetic or natural indigo, but they differ in pH range, working speed, color result, and fiber tolerance in ways that make each suited to different dyeing contexts. The fructose vat operates at high pH (pH 11–12) maintained with slaked lime (calcium hydroxide) and uses fructose (fruit sugar) as the reducing agent. The chemical reduction is: fructose is oxidized by the indigo molecule, converting insoluble indigo (blue) to soluble leuco-indigo (yellow-green), which can penetrate the fiber and then re-oxidize to blue on exposure to air. The fructose vat is slower to establish (typically 30–60 minutes at 50°C with regular gentle agitation before reaching full reduction) but gentle on fiber because fructose does not damage wool or other protein fibers at the working pH. The color result is often described as 'softer' or 'cleaner' blue because the fructose reduction tends to produce a more complete, even reduction without the grey-green cast that iron reduction can introduce. The iron/lime vat uses ferrous sulfate as the reducing agent alongside slaked lime. The mechanism is different: ferrous iron (Fe²⁺) reduces indigo directly to leuco-indigo, and the lime maintains the high pH needed for reduction (pH 10–12). The iron vat establishes faster than the fructose vat — typically 15–30 minutes — but ferrous iron can cause fiber damage with extended exposure on wool, producing a characteristic iron poisoning (harsh, weakened fiber) if the iron concentration is high or the exposure time is long. The iron vat also tends to produce colors with a slight cooler, greyer tone compared to fructose vat colors. For Patreon documentation, each vat type requires a complete record: vat type, indigo source and form (synthetic indigo powder, natural indigo cake, or Japanese indigo paste), indigo weight in grams, water volume in liters, reducing agent identity and weight, lime weight and source (slaked vs quicklime — quicklime requires hydration before use), initial and working pH measured with a calibrated meter, working temperature, establishment time before first dip, and the vat's visual indicators at the time of first use.

Explainers · 2026-06-26 · ~4,400 words

Patreon for natural dyeing creators: complete 2026 guide — mordant chemistry at the pH level, dye plant phenology documentation, indigo vat management, and the Apple Tax

Natural dyeing Patreons retain when they deliver the calibration data that a process video cannot carry: mordant chemistry at the pH level that explains why alum sulfate and aluminum acetate produce different results on the same fiber, dye plant phenology documentation that maps harvest timing to yield and color across the phenological window, and indigo vat management records that give patrons the health indicators and reduction potential measurements they need to maintain their own vats. Natural dyeing audiences are YouTube and Instagram-primary with high iOS rates — Apple Tax exposure begins November 1, 2026.

Who natural dyeing creators are on Patreon

Natural dyeing separates into four overlapping practices with distinct documentation needs. Dye educators teach the chemistry and process of mordanting, dye bath preparation, and color modification systematically; their Patreon content is the calibration data behind each result — mordant concentrations, pH measurements, dye bath records, and side-by-side fiber samples. Botanical dyers forage, grow, or source specific dye plants and document the plant-to-fiber pipeline from harvest through mordant selection to finished color; their Patreon content is the plant-specific documentation that no general guide covers. Indigo specialists work exclusively or primarily with indigo vat processes, either synthetic or natural, and document vat chemistry, maintenance, and troubleshooting at the operational level. Studio dyers integrate natural dyeing with fiber preparation (spinning, weaving, knitting) and document the full pipeline from raw fiber to finished project color planning; their Patreon content combines process documentation with color story context.

The commonality across all four is that natural dyeing outcomes depend on material-specific calibration data — mordant form and concentration, dye plant species and harvest stage, bath pH and temperature, modifier identity and concentration — that accumulates across sessions and cannot be derived from general principles alone. A video that shows a creator pulling a beautiful skein from a weld bath does not show the luteolin content of the weld at harvest stage, the alum concentration as WOF percentage, the bath pH, or the temperature curve — which are the parameters the viewer needs to reproduce the color. A Patreon that delivers that data is not optional for the patron who wants planned and reproducible results.

Mordant chemistry at the pH level

Alum sulfate vs aluminum acetate: the fiber-specific behavior difference

Both alum sulfate (potassium aluminum sulfate, KAl(SO&sub4;)&sub2;·12H&sub2;O) and aluminum acetate (Al(C&sub2;H&sub3;O&sub2;)&sub3;) fix dyes to fiber by coordinating aluminum cations with dye molecules and fiber functional groups. The critical difference is that they produce different solution pH values at standard mordanting concentrations, and those pH differences produce meaningfully different color depth and durability on protein versus cellulose fiber.

Alum sulfate dissociates in water to produce a mildly acidic solution, typically pH 3.5–4.5 at mordanting concentrations of 10–20% WOF (weight of fiber). This pH range is optimal for protein fibers — wool and silk — because the acid environment promotes hydrogen bonding and coordinate bonding between the aluminum complex and the protein chain without attacking the protein structure itself. At pH below 3.5, the acid begins to damage the protein; above pH 5.0, aluminum hydroxide begins to precipitate out of solution and deposits unevenly on the fiber surface rather than bonding uniformly. On cellulose fibers (cotton, linen, hemp), alum sulfate produces less durable mordanting because the acid pH works against the ionic mechanisms that bond aluminum to cellulose hydroxyl groups; cellulose mordanted with alum sulfate typically achieves 40–60% of the color depth achievable on wool from the same dye bath.

Aluminum acetate at the same WOF percentage produces a higher solution pH (pH 4.5–5.5) because the acetate ion acts as a weak buffer. This higher pH range dramatically improves aluminum bonding to cellulose — the aluminum cation coordinates with cellulose hydroxyl groups more effectively above pH 4.5, producing color depth that approaches the results achievable on wool. Aluminum acetate is the standard mordant for cellulose fiber in historical textile dyeing, not an alternative to alum sulfate but the correct tool for the fiber type.

For Patreon documentation, this distinction makes mordant form an essential record alongside concentration. A dye bath note that records “alum mordant, 15% WOF” is ambiguous: it could mean alum sulfate on wool (appropriate) or alum sulfate on cotton (likely to produce a duller, less washfast result than the creator intends to demonstrate). The documentation must specify mordant form, WOF percentage, solution pH measured with a pH meter or strip, fiber type, and mordant bath temperature (70–80°C for protein fiber, 60–70°C for cellulose to minimize fiber damage) and duration (45–60 minutes for full mordant uptake). Patrons who mordant at home with different fiber types can then understand why their result diverges from the creator’s reference and adjust their mordant selection accordingly.

Iron modifier effects: saturation and hue are separate variables

Iron modifier (ferrous sulfate, FeSO&sub4;·7H&sub2;O, sold as copperas) coordinates with the dye-mordant complex already on the fiber and shifts color in a way that affects saturation and hue independently — and the direction of each shift is specific to the dye class rather than being a simple “darkening.”

With flavonoid dyes (weld, goldenrod, onion skin, osage orange, birch leaves): iron modification shifts the yellow or gold hue toward green and olive by altering the flavonoid-aluminum complex electronic structure, while simultaneously reducing brightness. At low iron concentrations (1–2% WOF in the modifier bath), the shift is subtle — a slight greening and dulling of a yellow-alum result. At moderate concentrations (4–6% WOF), the result is a clear olive or bronze-green. At high concentrations (8–12% WOF), dark greenish-brown or khaki. The hue shifts toward the cool-green quadrant and the saturation drops simultaneously; a creator who documents this progression at 1%, 4%, and 8% WOF on the same fiber from the same dye bath gives patrons the complete modifier response map.

With tannin-rich dyes (black walnut, oak gall, sumac, pomegranate rind): iron produces dramatic darkening toward grey-black through a gallotannin-iron complex. The hue shift is minimal — the color moves toward neutral grey rather than a colored hue — and the saturation drops precipitously. This is the chemistry behind traditional iron-gall ink. For dyeing documentation, the relevant calibration is the iron concentration at which the color begins shifting and the concentration at which it reaches near-black.

With madder (alizarin and purpurin, Rubia tinctorum): iron modification shifts the red-orange hue toward muted reddish-brown or terracotta, with significant saturation reduction. The hue moves from warm-red toward a cooler, brownish-red; the saturation drops more than with flavonoids. A madder-alum result on wool is typically a clear red-orange (Scarlet-adjacent at pH 4.0; more brick-red at pH 5.5); the same fiber after iron modification at 3–4% WOF is a muted brown-red with grey undertone.

The documentation standard for iron modifier work covers: the pre-modification sample (dye class, mordant concentration and form, color description on fiber and photograph), iron concentration as WOF percentage, modifier bath pH (pH 4.0–5.0 keeps iron as ferrous ions in solution; above pH 6.0 iron precipitates as ferric hydroxide and deposits unevenly), modifier bath temperature (40–50°C — lower than the main dye bath because iron at high temperature on protein fiber causes iron poisoning, degrading the fiber), duration in the modifier bath (15–30 minutes), and the resulting hue shift described in terms of both hue direction and saturation change. A side-by-side sample card — pre-modification and post-modification on fiber from the same dye bath, photographed in consistent natural light — is the definitive Patreon deliverable for iron modifier documentation.

Tannin pre-mordanting and fiber type behavior

Tannin pre-mordanting is a distinct step used primarily on cellulose fibers before a primary aluminum mordant, and its behavior differs between hydrolyzable tannins and condensed tannins in ways that affect the final color. Hydrolyzable tannins (oak gall, sumac, pomegranate, myrobalan) deposit on cellulose fiber as a temporary anionic site that improves aluminum cation uptake in the subsequent alum or aluminum acetate bath. The tannin itself contributes a beige-tan base color that affects the final hue; oak gall tannin at 10% WOF on cotton produces a clear tan before any dye step. Condensed tannins (quebracho, chestnut, cutch) produce a similar anionic site but with a darker, redder base than hydrolyzable tannins. Document the tannin type, WOF percentage, bath pH (tannin baths are naturally acidic, pH 3.5–5.0), temperature, and the resulting fiber color before the primary mordant step — because the tannin base color modifies every subsequent dye result on that fiber.

Dye plant phenology: harvest timing as calibration data

The phenological window and why general harvest timing advice fails

Most published natural dyeing resources specify dye plant harvest timing as a calendar range or growth stage description without documenting how colorant yield and hue change across the phenological window. A creator who documents the phenological spectrum — harvesting from the same plant stand at multiple growth stages and recording the yield and color result at each — is producing calibration data that exists nowhere else in published form for that specific species and climate.

Calendar dates are not transferable between regions. A UK-climate weld harvest window (May–July for peak luteolin) is meaningless to a patron in the Pacific Northwest or Germany with different soil and temperature regimes. The transferable documentation is the plant growth stage photographed at harvest, the yield measured as grams of dried plant material per square meter of growing area, and the color result on a standardized mordant and fiber combination.

Weld (Reseda luteola): the phenological color and yield spectrum

Weld is the highest-yielding yellow dye plant in temperate cultivation and the clearest example of phenological color change across the growing season. The active colorant is luteolin, a flavonoid concentrated in the leaves and stems with the highest concentration during active vegetative growth and declining after flowering.

Rosette stage (before the flower spike emerges, typically April–early June in temperate climates): the plant is a flat rosette of leaves close to the ground. Leaf luteolin content is high but total plant biomass is lower than at later stages. Color result is a greenish-yellow on alum-mordanted wool, distinctly cooler than peak-season harvest. Yield in grams of dye material per square meter of growing area is at its seasonal minimum; harvest at this stage uses only the leaf material without access to the higher-yield stems.

Early spike emergence (flower spike visible but flowers not open): this is the documented peak-yield window. The plant biomass — leaves, stems, and the flower spike base — is maximized, and luteolin content in the leaves and stems is still high. Color result on alum-mordanted wool is a warm, clear yellow with good washfastness. Yield per square meter is at its seasonal maximum; harvest by cutting the plant at ground level takes all aerial parts including the stem.

Peak bloom (flowers fully open): yield drops 15–25% compared to early spike emergence because the plant has translocated some leaf energy into flower production. The color result is a slightly purer, less greenish yellow than early spike. Some dyers prefer peak bloom for color quality despite the lower yield.

Post-bloom to seed set: yield drops further as luteolin is redistributed into seed development. Color becomes more muted gold-beige. Seed can be collected for next year’s crop; document the dry seed weight per plant for germination planning.

The Patreon documentation for weld phenology records harvest stage as a photograph of the plant at harvest, plant fresh weight in grams, dried plant weight after drying to constant weight, dye bath volume (enough water to allow fiber to move freely), bath temperature at 80–90°C for 45–60 minutes, mordant system (alum sulfate or aluminum acetate, WOF percentage, pH), and the resulting color on a standardized fiber sample — 10g of pre-mordanted wool photographed in consistent light. Stack these records across harvest stages and the phenological color map takes shape across four or five posts.

Japanese indigo (Persicaria tinctoria): pre-flower harvest and indican content

Japanese indigo (ai, Persicaria tinctoria) is grown as an annual crop for fresh-leaf vat dyeing, and its phenological management differs from weld because the goal is not a dried dye material but the fresh leaf harvested at peak indican content. Indican is the indigo precursor — a glycoside that is enzymatically converted to indigo when the leaf cell structure is disrupted by bruising, fermenting, or processing.

Indican concentration in Japanese indigo leaf peaks before the plant begins flowering, typically when the plant has developed five to eight leaf pairs and is in active vegetative growth. Once the flower spike initiates — visible as a small bud cluster at the growing tip — the plant translocates carbohydrate and nitrogen toward reproduction, and indican concentration in the remaining leaves drops sharply. Harvesting after flower spike emergence yields 30–50% less extractable indigo than pre-flower harvest from the same plant.

Phenological documentation for Japanese indigo: photograph the plant at harvest to show growth stage (leaf pair count, presence or absence of flower bud), record fresh leaf weight in grams from a metered harvest area, then extract using the fresh-leaf method (leaves blended in cold water, liquid filtered and aerated to precipitate indigo) or the fermented leaf paste method. Yield documentation is grams of dried indigo paste produced per 100g of fresh leaf. Across harvest stages from vegetative peak to post-flower, this yield curve is unpublished data for the specific cultivar and climate. Patrons who grow their own Japanese indigo can use the creator’s curve as a reference for timing their own harvests.

Cultivar matters for Japanese indigo because different cultivars have different leaf indican content and growth habits. Document the cultivar name or seed source if known; if unknown, photograph the leaf shape and growth habit at harvest for comparison across sources. This level of cultivar-specific phenological documentation is not available in published form for most Japanese indigo cultivars grown in Western climates.

Onion skin accumulation records

Onion skin (yellow onion and red onion) is a widely used dye material that accrues through the kitchen rather than through intentional cultivation. Yellow onion skins contain quercetin (a flavonoid related to luteolin) and produce clear yellow-gold on alum-mordanted wool; red onion skins contain anthocyanins in addition to quercetin and produce a more complex yellow-brown that shifts toward green with iron modification.

The yield variable for onion skin is the ratio of dry skin weight to wool weight — typical use is 100–200% WOF (equal to or double the weight of the fiber) for full color depth. The Patreon value here is not phenological variation but accumulation documentation: how much dry skin (by weight) the creator collected over what period, the skin color range of the accumulated batch (all yellow outer skins versus mixed skins including the colored inner layers), and the resulting color depth and character on the reference sample. A creator who documents ten different onion skin batches with varying skin composition and WOF ratios gives patrons the color range map for this extremely accessible dye material.

Indigo vat management in depth

Vat health indicators as a diagnostic system

A working indigo vat has four visual health indicators that change in characteristic ways when the vat is out of balance, and reading them as a system rather than individually gives the most accurate diagnosis. The four indicators are: the flower (surface foam), the vat color, the dip color on freshly removed fiber, and the scratch test color.

The flower: a healthy vat produces blue-purple foam at the surface from the oxidation of leuco-indigo at the air-liquid interface. The flower should be blue-purple, not grey or brown. Grey foam indicates either excessive reduction (over-reduced vat where the indigo has been reduced beyond leuco-indigo to colorless reduction products that cannot re-oxidize to blue) or contamination from a dirty reduction agent. Brown foam indicates alkalinity imbalance in the direction of excessive lime or alkalinity causing side reactions. An absent flower means the vat is not actively reducing — either the reduction has stalled (temperature too low, reducing agent exhausted) or the vat is genuinely exhausted and requires fresh indigo addition.

Vat color: a working vat should be yellow-green below the surface when viewed through a glass vessel or with the surface foam cleared. This color is the leuco-indigo in solution — the reduced, soluble form of indigo. A vat that appears blue-purple below the surface contains unoxidized indigo in suspension (not fully reduced; the indigo particles are blue and not in solution). A vat that appears clear with a greenish tinge has fully reduced indigo in solution; a vat that appears blue below the surface needs more reduction time or additional reducing agent.

Dip color on freshly removed fiber: when fiber is removed from a working vat and held in air, the color on the surface should transition from yellow-green (leuco-indigo at the moment of removal) to blue within 30–120 seconds as the leuco-indigo oxidizes. If the fiber emerges blue (not yellow-green), the fiber surface is pulling blue indigo pigment particles from an incompletely reduced vat rather than absorbing leuco-indigo in solution. This produces a surface deposit that does not bond to the fiber and rubs off.

Scratch test: using a fingernail or wooden stick, scratch the surface of the freshly removed fiber (before full oxidation) and observe the inner color at the scratch. A yellow-green interior confirms that leuco-indigo has penetrated the fiber — the vat is working correctly. A blue interior confirms surface particle deposition without fiber penetration. Document the scratch test result for each dip session: it is the most direct health indicator for the vat’s working state.

Reduction potential measurement with an ORP meter

pH alone does not confirm a working indigo vat because pH measures acidity, not reduction state. A vat can be at the correct pH and still not reduce indigo if the reducing agent is exhausted or if the temperature is too low for the reduction reaction to proceed. Oxidation-reduction potential (ORP), measured in millivolts with an ORP meter (also called an oxidation-reduction potential probe or redox probe), directly measures the electron-donating capacity of the vat solution.

A working indigo vat in reducing conditions shows a negative ORP value, typically −200 to −600 mV depending on vat type and reduction state. The range −300 to −450 mV is the commonly cited working range for a healthy fructose or iron/lime vat. An ORP reading above −200 mV (less negative) indicates an oxidized or under-reduced vat that will not absorb indigo correctly; an ORP below −600 mV (more negative) indicates an over-reduced vat where the indigo has been fully converted to colorless reduction products and the dye capacity is temporarily lost.

For Patreon documentation, record the ORP at the start of each dyeing session, after any reducing agent or lime addition, and at the end of the session. The ORP trajectory across a session — starting value, any adjustments made and their effect on ORP, and ending value — is actionable documentation that patrons who own an ORP meter can apply directly to their own vats. The ORP measurement is not dependent on vat type or scale in the way that reducing agent concentration is; it measures the outcome of the reduction chemistry regardless of which reducing agent produced it.

ORP meters are inexpensive (most aquarium-grade ORP probes work reliably in indigo vats, available for $20–50), require periodic calibration with an ORP calibration solution (200 mV or 468 mV standard solutions), and need rinsing between uses. Document the calibration date and calibration solution standard with each set of ORP measurements so patrons can interpret the values relative to your probe’s calibration state.

Fructose vs iron/lime vat comparison

The fructose vat and the iron/lime (ferrous sulfate/slaked lime) vat are the two most common non-fermentation vat types, and they differ in pH range, working speed, color character, and fiber tolerance in ways that make each suited to different dyeing contexts.

Fructose vat chemistry and setup: fructose (fruit sugar or crystalline fructose) reduces indigo in alkaline conditions by being oxidized itself. The vat requires slaked lime (calcium hydroxide) to maintain pH 11–12, which is necessary for both the fructose reduction reaction and for keeping leuco-indigo in solution as the calcium leuco-indigotate complex. Setup: dissolve indigo powder in a small volume of water with a few drops of rubbing alcohol or methylated spirits to wet the hydrophobic indigo particles; add slaked lime at approximately twice the weight of the indigo; add fructose at approximately two to three times the weight of the indigo; bring the vat to 50°C and maintain with gentle agitation for 30–60 minutes until the vat turns yellow-green below the surface. The fructose vat is gentle on protein fibers because fructose does not attack the protein chain at the high pH of the vat, provided exposure time is not excessive (under 20 minutes per dip for wool). Color result is a clean, warm blue with relatively low grey undertone.

Iron/lime vat chemistry and setup: ferrous sulfate (FeSO&sub4;·7H&sub2;O, copperas) reduces indigo directly by donating electrons: Fe²♠ is oxidized to Fe³♠ while indigo is reduced to leuco-indigo. The lime maintains the high pH required for reduction (pH 10–12). Setup: dissolve indigo as above; dissolve ferrous sulfate in warm water separately; combine into the vat with slaked lime addition; bring to 40–50°C (the iron vat typically does not require as high a temperature as the fructose vat to establish). Working pH for the iron/lime vat is typically pH 10–11 — slightly less alkaline than the fructose vat. The iron vat establishes in 15–30 minutes. The iron vat can damage wool with extended exposure (iron poisoning) because ferric ions oxidized from ferrous iron can react with the sulfur amino acids in the wool protein chain. Keep individual dip times short (5–10 minutes maximum) and ensure good rinsing after dyeing. Color result tends toward a slightly cooler, greyer blue than the fructose vat result from the same indigo concentration.

Documentation standard for both vat types: record vat type; indigo source (synthetic indigo, natural indigo paste, or Japanese indigo fresh leaf extract), indigo weight; reducing agent identity and weight; lime type (slaked vs quicklime) and weight; water volume; initial pH; initial ORP; working temperature; establishment time; vat indicator assessment at the first-use point (flower color, vat color below surface, dip color, scratch test result); number of dips for the reference sample; total dip time; and the color result on the standardized fiber sample. When a vat is refreshed with additional reducing agent, record the refreshment inputs and the resulting ORP change. When a vat is exhausted and retired, record the total amount of indigo introduced, the total fiber weight dyed, and the number of sessions.

Comparative Patreon content — the same fiber and indigo concentration dyed in a fructose vat and an iron/lime vat with documented chemistry — gives patrons the direct color comparison no published resource provides because most books and guides document one vat type in isolation.

Tier structure for natural dyeing creators

Dye educators

Process documentation tier ($12–18/month): each session’s dye bath record (plant material, mordant form and WOF%, pH, temperature curve, duration, modifier if used, and color result on fiber sample photographed in consistent light). The record format should be consistent across sessions so patrons can compare entries directly. Technical deep-dive tier ($30–45/month, capped 8–10 patrons): same documentation plus a color consultation slot each month — patron submits their own dye bath record and the creator identifies the likely source of color discrepancy. This tier delivers the chemistry expertise that no tutorial can replace.

Botanical dyers and foragers

Plant documentation tier ($10–15/month): species-specific dye records including harvest stage photographs, yield data (dry weight per volume or area of plant material), and color results on standard mordant combinations. The archive grows into a species library that patrons consult when they encounter a dye plant in the field. Seasonal sample tier ($25–40/month, capped 6–8 patrons): same documentation plus quarterly postal samples of dyed fiber from documented batches, labeled with batch identifiers.

Indigo specialists

Vat records tier ($15–20/month): each vat session’s complete record (vat type, chemistry inputs, ORP and pH at key points, indicator assessment, dip log, color result). Vat troubleshooting tier ($35–55/month, capped 6–8 patrons): same records plus one vat troubleshooting consultation per month — patron submits their own vat readings and symptom description; creator diagnoses and suggests adjustment. This tier is high value for patrons who maintain their own vats and struggle with consistency.

Apple Tax for natural dyeing creator audiences

Natural dyeing creator iOS rates follow their content platform distribution. YouTube natural dyeing process and tutorial content: 55–70% iOS — natural dyeing attracts a craft-primary audience that is highly mobile, similar to fiber arts content. YouTube indigo vat and specialty chemistry content: 50–65% iOS — slightly more desktop use among patrons who are following detailed instructions during their own dyeing sessions. Instagram botanical dyeing photography (fiber samples, plant-to-skein color comparison, mordant palette shots): 75–85% iOS — natural dyeing photography is visually compelling and performs strongly in Instagram discovery for craft and sustainable textile audiences. TikTok natural dyeing transformation content (raw fiber or white yarn to finished color): 70–80% iOS.

The Apple Tax calculation on November 1, 2026: a natural dyeing creator at $350/month Patreon revenue with 60% iOS faces approximately $350 × 0.60 × 0.30 = $63/month ($756/year) in Apple fees. At $500/month with 65% iOS: approximately $97.50/month ($1,170/year). At $400/month with 75% iOS (Instagram-primary botanical dyer with visual content): approximately $90/month ($1,080/year).

The fix requires enabling Patreon’s web-only billing toggle before October 31, 2026. Update Instagram bio links, YouTube channel links, and TikTok bios to point to the Patreon web URL rather than the Patreon app link. Verify the fix by completing a test subscription from an iOS device via Safari — a patron who subscribes through Safari on iPhone does not generate an iOS-billed subscription and incurs no Apple Tax.

Natural dyeing creator Patreon tiers and structure overview · Patreon for spinning creators · Patreon for weaving creators

KeepTier is a self-hosted membership page for creators who want 100% of their tier revenue and zero Apple tax. Plans start at $9/month.