Gluten-Free Sourdough Flours: The Complete UK Bakers Guide

Every gluten-free flour behaves differently in a sourdough starter and dough. Here is the complete UK bakers guide to which flour does what, exact hydration and structure adjustments for each, and where to source them.

Why gluten-free sourdough is different

Traditional wheat sourdough relies on gluten networks to trap the CO2 produced by wild yeasts. Without gluten, gluten-free flours need other structural help — usually starches, gums or eggs. Wild fermentation still works, but the loaf structure comes together differently. Understanding each flour's role is the difference between a brick and a bakery-quality loaf.

The 6 essential gluten-free flours for sourdough

1. Brown rice flour — the workhorse (60-70% of your blend)

Character: Mildly sweet, tender crumb, good browning. Whole-grain enough to feed wild yeasts naturally.

Hydration: Absorbs 65-70% by weight — similar to wheat bread flour.

Best for: Everyday sandwich loaves, pancakes, base of any GF blend.

UK sources: Doves Farm, Waitrose Cooks Ingredients, Amazon Fresh.

2. Buckwheat flour — the flavour builder (10-20%)

Character: Deep, nutty, slightly earthy. Despite the name, buckwheat is not wheat — it is a seed. Naturally gluten-free.

Hydration: Very absorbent, needs 75-80% hydration. Reduces gumminess in the crumb.

Best for: Adding depth of flavour, seeded batards, rye-style loaves.

UK sources: Bob's Red Mill (Waitrose), Ocado.

3. Sorghum flour — the structure builder (10-15%)

Character: Neutral, slightly sweet, pale colour. High protein content (7-11%) gives structural strength.

Hydration: Absorbs 65-70%. Behaves similarly to soft wheat flour.

Best for: Adding protein and structure to GF blends. Almost undetectable in flavour.

UK sources: Amazon, health food shops. Look for stone-ground.

4. Teff flour — the specialty add (5-10%)

Character: Dark, malty, tangy — the flour used for Ethiopian injera. Very high fibre.

Hydration: Very thirsty flour, absorbs up to 90%.

Best for: Dark artisan loaves, when you want a rye-like flavour without rye.

UK sources: Tobia Teff (UK importer), specialist grocers, Amazon.

5. Oat flour — the softener (10-15%)

Character: Sweet, mild, tender. Note: oats are naturally GF but often processed near wheat — always buy certified gluten-free oats if you need strict avoidance.

Hydration: Absorbs 60-70%. Adds tenderness to the crumb.

Best for: Softening the crumb, morning breads, muffins made with sourdough discard.

UK sources: Waitrose Duchy, Doves Farm, Nairn's certified.

6. Chickpea (gram) flour — the binder (5-10%)

Character: Distinctly beany, high protein, dense. A little goes a long way.

Hydration: Absorbs 60% and forms a gel that helps bind GF dough.

Best for: Adding protein and structure. Not for everyday loaves — best in specialty flatbreads and socca-style bakes.

UK sources: Asian grocers, Amazon, most large supermarkets.

A reliable starter blend for GF sourdough

• 60g brown rice flour
• 20g buckwheat flour
• 15g sorghum flour
• 5g chickpea flour

Feed this blend the same as wheat: equal parts starter, blend and water by weight. Expect slower fermentation for the first week as the wild yeast population adjusts.

What to avoid

• Wheat starch: Contains trace gluten. Not suitable for GF sourdough.
• Rye: Contains gluten (a different protein than wheat). Not GF.
• Barley: Contains gluten. Not GF.
• Spelt: Contains gluten (ancient wheat variety). Not GF.
• Cornflour: Fine for thickening sauces, useless in sourdough — no structure, no fermentation food.

Structure aids beyond flour

Because GF flours lack gluten, most bakers add a structural aid:

• Psyllium husk (5-8% of flour weight): The single best addition. Forms a gel that mimics gluten's elasticity. Buy whole, ground fine yourself.
• Xanthan gum (0.5-1%): Effective but many people prefer to avoid it. Adds elasticity.
• Egg white or aquafaba: Traditional binder for GF baking. Adds structure and browning.

Where the flours affect fermentation

Wild yeasts thrive on carbohydrates. Brown rice flour and buckwheat feed them fastest. Purely white starch-heavy blends (like commercial GF flour mixes) feed them slowly and result in weak starters. Always include at least 30% whole-grain gluten-free flour (buckwheat, teff, oat) in your starter maintenance blend.

Note on cross-contamination

Wheat flour dust travels metres in a kitchen. If you also bake with wheat, keep GF flours in sealed containers on a separate shelf, use dedicated bowls and spoons for GF work, and always mix GF flour outside on a covered surface. This is essential if the loaves are for someone with strict wheat avoidance.

Have questions or want a specific blend recommendation for what you bake? Get in touch — we answer every email.