Three calculators in one — figure out your dough hydration, get exact starter feeding amounts, and estimate bulk fermentation time based on temperature.
My first attempt at gluten-free sourdough was a brick. Not metaphorically — it actually could have been used as a doorstop. The recipe said "ferment until doubled" but my GF dough didn't double, it barely grew 50%, and I had no idea if that was normal or if something went wrong. Spoiler: it was totally normal for GF dough.
Gluten-free sourdough plays by different rules than wheat sourdough. The hydration is higher, the fermentation times are shorter, and the visual cues are different. Once I stopped comparing my GF dough to wheat tutorials on YouTube, things clicked.
These three calculators handle the math that used to trip me up. The hydration calculator lets you see exactly how wet your dough is (GF sourdough usually runs 85-100%). The feeding calculator tells you how much flour and water to use for any starter ratio. And the fermentation timer gives you a realistic time window based on your kitchen temperature — because a 68°F kitchen and an 80°F kitchen produce wildly different results.
All of this is calibrated for gluten-free flours, which absorb water differently and ferment at different rates than wheat. If you want the full walkthrough on maintaining a GF starter and baking your first loaf, our Sourdough Masterclass goes step by step with video demos.
Sourdough isn't just a recipe — it's a living process. Your starter contains billions of wild yeast cells and lactic acid bacteria that convert sugars in flour into carbon dioxide (for rise) and organic acids (for flavor). Understanding what drives this process helps you troubleshoot when things go sideways.
Temperature is the single biggest variable in fermentation. At 65°F, your dough might take 10+ hours to bulk ferment. At 82°F, it could be done in 3-4 hours. This isn't a problem — it's a tool. Cold fermentation develops more complex, tangy flavors. Warm fermentation is faster and milder. Most home bakers find the sweet spot around 75-78°F.
If you can't control your kitchen temperature, use these tricks: your oven with just the light on stays around 78-80°F. A microwave with a cup of hot water creates a warm, humid environment. In winter, the top of your fridge is often warmer than the counter.
GF sourdough runs wetter than wheat sourdough — typically 85-100% hydration vs. 65-75% for wheat. This isn't a mistake; GF flours need more water to hydrate properly, and the extra moisture helps compensate for the lack of gluten structure. If your GF sourdough dough looks "too wet," it's probably right where it needs to be.
The exception is if you're using psyllium husk as a binder — it absorbs a lot of water, so you may need to add even more liquid. Start with the recipe amount, let it rest for 10 minutes, and add water 1 tablespoon at a time until the dough is wet, sticky, and just barely holds its shape.
A healthy starter should double in size within 4-6 hours of feeding at room temperature. It should smell tangy and yeasty — like sourdough, not like nail polish remover (which means it's starving and too acidic). Bubbles on the surface and throughout are good signs. If it passes the "float test" (a spoonful floats in water), it's ready to bake with.
For GF starters specifically: brown rice flour and buckwheat flour work best. Avoid flours with a lot of fiber (like coconut flour) as the primary starter flour — they don't ferment as predictably. Feed at a consistent time each day if you keep it on the counter, or once a week if refrigerated.
GF sourdough typically runs higher hydration than wheat sourdough — usually 85-100% for the dough and 100% for the starter. GF flours absorb water differently and need more moisture to develop structure. If your dough feels too stiff, add water in small increments (1 tablespoon at a time) until it's wet and sticky but still holds some shape.
Look for a 50-75% volume increase and lots of bubbles on the surface and sides. The dough should feel airy and jiggly when you shake the container gently. For GF sourdough, you're less likely to see the dramatic dome that wheat dough gets — rely on bubble activity and volume more than shape.
Absolutely. A GF sourdough starter works the same way as a wheat one — wild yeast and bacteria ferment the flour, producing rise and flavor. Use brown rice flour or a mix of brown rice and buckwheat flour for your starter. Feed it at a 1:1:1 ratio (starter : flour : water by weight) daily on the counter or weekly in the fridge.
The sweet spot is 75-80°F (24-27°C). Below 70°F, fermentation slows dramatically and can take 8+ hours. Above 85°F, fermentation speeds up but the flavor gets more sour and acidic, and you risk over-proofing. If your kitchen is cold, use your oven with just the light on — it usually creates a steady 78-80°F environment.
Plan on 7-14 days from scratch. You'll see some bubbling activity around day 3-5, but the starter needs more time to develop a stable yeast-bacteria population. It's ready when it reliably doubles in size within 4-6 hours of feeding at room temperature. Be patient — many people give up at day 5 when activity temporarily stalls.
A 1:1:1 ratio (equal parts starter, flour, water) is the standard daily maintenance feed. A 1:2:2 ratio is a "stiff feed" that slows fermentation, good when you need to delay baking. A 1:5:5 ratio is for when you won't bake for days — it gives the starter more food so it stays healthy longer between feeds. Our calculator shows you exactly how much flour and water for any ratio.
Our Sourdough Masterclass walks you through every step — from building a starter to pulling a perfect loaf from the oven.
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