The free sourdough companion
Sourdough, without the guesswork.
A bake timeline that moves when your dough does, a calculator that starts from your pot, and a starter log that learns how long yours takes to peak. Free, no account, and nothing leaves your phone.
Tested schedules, from a forgiving first loaf to 82% open crumb.
To grow a starter, day by day — including the two that look like failure.
Faster fermentation for every 8°C / 14°F warmer. The app re-times each step to match.
Accounts. Your bakes live on your device; there is no server to send them to.
The app
A kitchen timer that reads the room.
Recipes give you times written for someone else's kitchen. OpenSourdough starts from yours — its temperature, your pot, your starter — and keeps adjusting while you bake.
The plan moves when the dough does.
Pick a schedule and every step gets a time: levain, folds, shaping, fridge, oven. Tap done and the rest of the day re-plans around what actually happened. Dough not ready? Give it fifteen more minutes and everything after it moves too.
- Scaled to your kitchen. Enter the dough temperature and fermentation stretches or shrinks to suit.
- Says what “done” looks like. Every step describes the dough you are waiting for, not just a time.
- Alerts for each step while the app is open.
Start from the pot, not the flour bin.
The real limit on a loaf is what you bake it in. Tell the calculator your vessel and it sizes the dough to fill it properly — then lists every gram to weigh.
- Baker's percentages done honestly. The flour and water inside your levain are counted, so the water you pour is actually right.
- Scale four ways — by pot, flour, dough weight or number of loaves.
- Water temperature worked out for the dough temperature you want.
A starter log that learns your jar.
Log a feed, tap when it peaks. After a few feeds the app knows how long your starter takes — and tells you how far ahead to build a levain so it goes in at its best.
- Levain builder that works backwards from what the formula needs.
- A journal that keeps each bake's formula, temperature and rating, so one loaf can teach the next.
Try it
Your kitchen sets the clock.
Yeast roughly doubles its pace with every 8°C (14°F). Drag the dough temperature and watch the overnight country loaf re-time itself — the same maths the app runs on every bake.
At 68°F the bulk ferment takes about 5h 39m; at 80°F, about 3h 10m. Same recipe, same flour.
Right about what this schedule was written for. Start to finish: 27h 22m.
Starter guide
Grow a starter from flour and water.
One jar, about a kilo of flour, one to three weeks. The walkthrough says what to do each day and — more usefully — what you should expect to see.
- Day 1
Mix it
50 g whole rye, 50 g water, somewhere warm.
- Day 2
Do not trust the bubbles
Early fizz is other bacteria, not yeast.
- 3–4
The quiet days
Flat and sour-smelling. Most jars get thrown out here. Keep going.
- 5–9
A rise that repeats
Then feeding twice a day to make it reliable.
- 10+
Doubles in 4–8 hours
That is a starter. Bake.
Schedules
Five loaves, tested and timed.
Each comes with the full formula in grams and every step laid out on a clock — read it here, or open it in the app and let the timers run.
Country loaf, overnight
The default. Build the levain in the morning, bulk in the afternoon, shape at night, bake first thing.
Country loaf, same day
Levain at breakfast, bread by dinner. No fridge step, so the timing is tighter and the flavour is milder.
First loaf, 70%
Stiffer dough, fewer folds, more margin. Start here if a previous loaf turned into a puddle.
Open crumb, 82%
High hydration, gentle handling, long cold proof. Wants strong flour and a starter that is firing reliably.
Sourdough focaccia
No shaping, no scoring, no Dutch oven. The forgiving one.
Read the dough, not the clock. Every time on a schedule is a starting point
Troubleshooting
Start from what you saw.
Not from what you think you did. Each problem is keyed to the loaf or the jar in front of you, with the likely cause and what to change next time.
Dense, tight crumb
Almost always an under-fermented bulk, or a levain that was not lively when it went in.
What to change →Gummy, sticky crumb
Two different faults look identical: cut too soon, or baked too little.
What to change →Flat, spread out, no height
Over-fermented dough, weak shaping, or more water than the flour can carry.
What to change →No oven spring, the score did not open
Over-proofed dough has no lift left.
What to change →Too sour
Long cold proofs, whole grain, and a starter that sits hungry all push acetic acid up.
What to change →It is not rising
Usually too cold, or fed too rarely.
What to change →Install
On your home screen in ten seconds.
No app store and nothing to wait for. It installs straight from the browser, opens full-screen, and works offline — which is the useful part with floury hands.
Open
Free, and yours.
OpenSourdough is built to be the opposite of a subscription app: no sign-up, no paywall, no data harvested. Everything it knows about your baking stays in your browser.
No account
Nothing to sign up for or log into. Open it and bake.
Stays on your device
Bakes, feeds and notes are stored in your browser, not on a server.
Works offline
Once it has loaded, it runs with no signal — on a shelf, by the oven.
An ad-free app
This website carries a few ads to stay free. The app has none — nothing between you and a timer.
Your next loaf starts tonight.
Build the levain before bed, bake in the morning. The overnight country loaf is the one to start with — the app will tell you when to do everything else.