Is sourdough gluten-free? No, unless it’s made from gluten-free flour

No. Ordinary sourdough contains gluten. Wheat, rye and spelt sourdough are made from gluten-containing flour, and the long fermentation doesn’t remove enough of it for coeliac (celiac) disease.

Why the myth exists

Sourdough fermentation breaks down some gluten, and some people without coeliac disease find sourdough easier to digest. That’s where “sourdough is gluten-free” comes from. For coeliac disease it doesn’t hold: a normal sourdough loaf still contains far more gluten than the 20 mg/kg limit for a gluten-free claim.

Gluten-free sourdough

Real gluten-free sourdough exists: a starter and dough made from gluten-free flours such as rice, buckwheat, sorghum, teff or millet. Bakeries that make it label it gluten-free, and dedicated gluten-free bakeries make the best of it. At home, a gluten-free starter works just like a wheat one.

Eating out

“Artisan sourdough” on a menu or in a café is wheat unless it says gluten-free. In a mixed bakery, ask how the gluten-free bread is kept apart, because flour dust travels.

Keep reading

• The Hidden-Gluten Watchlist: the 15 forbidden names and the ones to check
• Spelt sourdough and coeliac disease
• Is spelt gluten-free?
• Which grains are gluten-free?
• The Flour Library

Sources: Codex Alimentarius (gluten-free = 20 mg/kg or less), EU Regulation 828/2014, Coeliac UK, NHS. We inform, we don’t diagnose: for medical questions, your doctor or dietitian has the last word.