Gluten-free formula adaptation: hydration, gum dosage and starch blending in baker's percentage

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Gluten-free is a rebuild, not a removal

You cannot make gluten-free bread by taking a wheat formula and deleting the gluten — there is nothing left to trap the gas. Gluten-free baking is a structural rebuild: you replace the gluten network with a blend of starches plus a hydrocolloid binder, and you flood the system with water so those hygroscopic starches and gums can hydrate and gel. The companion article A1-gluten-free-flour-systems explains why each flour and gum behaves as it does. This article is the recipe book: how to write the formula, in baker's percentage, and how to convert one you already have.

Every formula here uses baker's percentage with the GF flour or blend as 100%; every other ingredient is (weight ÷ flour weight) × 100. The pay-off is the same as for wheat — one formula scales from a 300 g test bake to a 100 kg plant run — but three numbers move dramatically when you go gluten-free, and they are the spine of this article: hydration, binder dosage and the starch blend.

The mental switch that fixes most gluten-free bread: you are making a batter, not a dough. There is nothing to knead, you give it a single rise, and you bake it longer.

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The three numbers that change

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1. Hydration roughly multiplies by 1.5×. A wheat tin loaf runs ~58–65% water; the gluten-free version of the same loaf wants ~90–100% and pours like a thick batter. Research bears this out: GF breads have been optimised across a 70–120% water range, and the sweet spot depends on both the binder and the starch base. On a maize-starch base (2% hydrocolloid), binder-differentiated optima were found — xanthan ~110%, psyllium ~90%, HPMC ~80% — but the 90%-water/psyllium/maize-starch formulation produced hollow bread in that study. On a rice-flour base all three hydrocolloids performed best at ~100%, making that the safer starting point for the rice-based blends used throughout this article. Set your starting water by flour base, then adjust to a thick, just-pourable batter. See the table below.

2. A binder replaces the gluten. The hydrocolloid builds the elastic film that holds fermentation gas. Working dosages (% of flour): xanthan 0.2–0.5% for cakes and cookies rising to ~1–2% for bread; guar 0.5–1.0% (a 1:1 swap for xanthan); HPMC 0.5–3.0% (uniquely, it gels on heating to support oven spring); and psyllium 2–5%, which also delivers a big shelf-life gain. King Arthur's bench rule of ~¼ tsp xanthan per cup of flour (more for bread, less for cookies, never more than ~1 tbsp per recipe) maps onto the low end of those weight figures. See the gum-dosage table below.

3. The flour is a blend. No single GF flour works alone. A reliable from-scratch white blend is rice flour 50% + tapioca starch 25% + potato starch 25% — a neutral bulking base, the elastic/chewy component, and the lightener. See the starch-blend table below.

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Converting a wheat formula to gluten-free

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The clearest way to learn the method is to put a wheat loaf and its gluten-free rebuild side by side (see the conversion formula card below). Five moves take you from one to the other:

1. Swap the flour 1:1 by weight for a GF starch blend (or a ready blend).
2. Add the binder — xanthan and/or psyllium — to replace the gluten film.
3. Raise the water ~1.5× (here 62% → 95%); the mix turns from dough to batter.
4. Lift the yeast and sugar a little and add an egg for protein structure (omit for vegan).
5. Change your hands for a spatula: mix 3–4 minutes to a smooth batter, give it a single rise to the tin rim, and bake longer to a ~98°C core. Plain (binder-free) GF all-purpose flour will not make a decent yeast loaf without these changes.

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From-scratch white sandwich loaf

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When you want full control, build the blend yourself (see the white-loaf formula card below). The blend — rice 50 / tapioca 25 / potato-starch 25 — is the 100% base:

That makes ~1.53 kg of batter — one large 2 lb tin loaf or two 1 lb tins. Gel the psyllium in part of the warm water first, beat everything to a smooth thick batter, scoop into a greased tin, one rise to the rim, then bake 200°C fan ~40 min to a 98°C core and cool fully before slicing — the crumb sets on cooling. Allergen: when whole egg is used it is a mandatory declarable allergen under EU Regulation 1169/2011 — any product derived from this formula must declare 'CONTAINS: EGG'. Buy the components from the catalogue: Eurostar or Peacock rice flour, Bronisław potato starch (protein 0.2 g, no allergens), Malmon whole psyllium, Doves Farm Xanthan Gum (note: spec dated 2010 — confirm current allergen status from latest COA before use) and Olympic sunflower oil.

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Fibre brown loaf — let the blend carry the binder

A ready blend removes a variable: Doves Farm GF Brown Bread Blend already contains xanthan (plus buckwheat, carob and sugar beet fibre), so you add psyllium only for elasticity and shelf life (see the brown-loaf formula card below):

Start the water a touch lower (90%) because the blend's 5.3 g/100 g fibre keeps absorbing — that fibre may even support a "source of fibre" claim on the finished loaf (verify per serving). Bake slightly cooler (195°C fan) to keep the darker crumb from over-browning. The same logic applies to Doves Farm GF White Bread Blend, which also carries xanthan; only the binder-free Doves Farm GF Plain White needs you to add your own gum.

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The fastest route: a complete mix

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For volume production with the lowest contamination and consistency risk, a complete mix wins. IREKS SINGLUPLUS is used at 100% addition — it is the flour base — with the entire binder system (xanthan E415 + HPMC E464 + psyllium) and a soya-protein boost already built in (see the ready-mix formula card below):

You add only water, yeast and optional oil. Quality note: the water and yeast here are typical practitioner values — the spec confirms only the 100% addition rate, so follow the IREKS recipe card for exact dosing. Note the allergens: SINGLUPLUS contains soy and cannot exclude milk traces — the spec's internal 'lactose ≤100 mg/kg' threshold does not exempt from a milk-protein allergen declaration; any product made with SINGLUPLUS must declare 'may contain MILK' as well as 'CONTAINS: SOY' under EU Regulation 1169/2011. If you need a dairy-and-soy-free profile, build from scratch instead. The choice between the three routes — from scratch, ready blend, complete mix — is a trade between control and risk (see the figure below).

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Rolls and muffins: the formula bends to the format

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Dinner rolls want a stiffer batter that holds a scooped mound, so drop the hydration and lean on egg for structure (see the rolls formula card below): a rice 60 / tapioca 25 / potato 15 blend, xanthan 0.5%, psyllium 3%, egg 12%, water 85% — total 212.5%, ~18 rolls at ~70 g. Pipe or scoop mounds, prove, egg-wash and bake ~200°C to a ~96–98°C core. Allergen: egg is a mandatory declarable allergen under EU Regulation 1169/2011; egg-wash is a second allergen touchpoint — declare 'CONTAINS: EGG' on any product derived from this formula.

Muffins and cakes follow the opposite rule on gum. Here egg protein and baking powder do the structural work, so you use little or no added gum — over-dosing an egg-rich, chemically leavened batter makes it gummy. The muffin formula card below runs a rice 40 / maize 30 / potato 30 blend with just xanthan 0.2%, baking powder 4%, sugar 70%, egg 50%, milk 55% and oil 45% — total 324.7%, ~12 muffins at ~80 g. Allergen: this formula contains both EGG (150 g) and MILK (165 g), which are mandatory declarable allergens under EU Regulation 1169/2011 — any product derived from this formula must declare 'CONTAINS: EGG, MILK'. The commercial shortcut is IREKS GF Muffin-Mix (100% addition; contains MILK; may contain SOY — must declare 'CONTAINS: MILK, may contain SOY'); Domson Baking Powder and Fermipan dried yeast round out the shelf.

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Starch blending: who does what

The blend is an engineering choice, not a flavour one (see the starch-blend table below):

• White rice flour (40–60%) — the neutral, white, fine bulking base; also a driver of the high water demand.
• Tapioca starch (20–30%) — the chew, the crust gloss, the bit of stretch.
• Potato starch (10–25%) — lightness and structure, but it retrogrades fast, so it is the prime suspect when a loaf goes hard by day two; balance it with tapioca and raise psyllium to 3–5% to extend softness.
• Maize/corn starch (0–30%) — light, near-white structure (the base of SINGLUPLUS).
• Buckwheat (0–20%) — a naturally gluten-free pseudocereal for colour, flavour and nutrition; beyond ~20% the crumb turns dark and bitter.

A warning that belongs in red ink: oat flour is not gluten-free. Agrol Oat Flour is nutritionally tempting (protein 13 g, fibre 10.3 g per 100 g) but its own spec declares it contains gluten with cross-contamination risk — oats are a gluten-containing cereal under EU law, so it can never go into a product you intend to label gluten-free.

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Faults that live in the formula

Most GF bread faults are fixed on paper, not at the bench (see the fault table below):

• Dense, low, poor rise → too little binder or too stiff a batter; raise xanthan to 0.4–0.5% or psyllium to 3–4% and push hydration toward 95–100%.
• Gummy, wet crumb → over-dosed gum, or under-baked; cut gum below 0.5%, bake to a 98°C core, never slice warm.
• Crumbly, falls apart → not enough binder or no elastic component; add psyllium and/or tapioca.
• Stales by day 2 → too much potato starch; swap some for tapioca and lift psyllium to 3–5% (psyllium cut crumb firmness 65–75% over 72 h in trials).
• Collapsed centre → over-proofed or over-hydrated for the binder; prove only to the rim, or move to a higher-binder system that tolerates ~100–110% water.

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Food-safety and allergen note (flagged for review)

All numeric specs above come from first-party supplier spec sheets, but gluten, allergen and nutrition data must be confirmed against the current COA before any label claim. SPEC CURRENCY WARNING: the Doves Farm specs cited here date from 2013–2014 (12–13 years old), the IREKS specs from 2017–2020 (6–9 years old), and the Doves Xanthan Gum spec from 2010 (16 years old) — the oldest in this dossier. Allergen management, line-sharing status and certification can change materially over these timescales. Treat every allergen and nutrition figure here as provisional pending current COA confirmation.

The legal bar for a "gluten-free" claim is ≤20 mg/kg (20 ppm) gluten in the finished product, verified by ELISA (R5) — a recipe change re-opens that test. Specifically: Agrol Oat Flour contains gluten and is unsuitable for GF products; IREKS SINGLUPLUS contains soy and cannot exclude milk traces — the internal 'lactose ≤100 mg/kg' figure is not an exemption from declaring milk as a potential allergen; IREKS Muffin-Mix contains milk and must declare soya traces; Doves Farm Plain White is made on a line where nuts, sesame, soya and milk are used; the dedicated-plant Doves blends test <20 ppm per batch but still store wheat on site (segregated); Doves Farm Xanthan Gum is packed on a line that also handles dairy — a potential allergen touchpoint. The formula cards in this article also introduce allergens directly: the white loaf and rolls include EGG, and the muffin includes EGG and MILK — all are mandatory declarable allergens under Regulation (EU) No 1169/2011.

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Coverage report

Solid: the three governing numbers — hydration (~80–110%, binder-dependent), binder dosage (xanthan/guar/HPMC/psyllium), and the starch-blend ratios — are cross-checked across King Arthur, BAKERpedia and peer-reviewed studies, and every formula card's internal arithmetic has been verified self-consistent. Six cards cover the conversion method plus the GF bread/roll/muffin canon, and eight first-party spec sheets anchor the product numerics and allergens.

Thinner: product-specific numerics (protein, fibre, binder systems, the 100% addition rate) are single-source first-party spec sheets — appropriate as product data but not independently cross-checkable, hence specs_cross_checked: false. The SINGLUPLUS water/yeast values are typical practitioner figures, not spec-confirmed. Volume-to-weight gum conversions are approximate.

Follow-up: confirm Doves Farm / IREKS / Agrol allergen and gluten data in writing before any GF or allergen labelling; add a sourdough GF formula and a high-hydration (psyllium-heavy) artisan loaf in a later pass; cross-link to A8-bakers-percentage-fundamentals and A8-scaling-and-yield-conversion, and to A1-gluten-free-flour-systems for the underlying ingredient science.