Sourdough Starter Tracker with Feeding Reminders

Yes. Boule is a sourdough starter tracker for iPhone that logs each starter's feedings, counts down to the next one, and reminds you when it is due. It also records how much the starter rises between feedings and keeps notes on your bakes, all stored on your device.

A starter kept at room temperature is typically fed once or twice a day, while a refrigerated starter can go about a week between feedings. The right cadence depends on your kitchen temperature, flour, and how active you need the starter to be. Boule lets you set a custom cadence per starter and counts down to each feeding so the schedule runs itself.

A single missed feeding rarely kills a starter — it usually just gets sluggish and more sour, and a feeding or two brings it back. In Boule, a missed feeding softens the starter into a rest state rather than triggering guilt prompts, and the countdown picks up again when you log the next feed.

Baker's percentages express every ingredient as a percentage of the total flour weight — so 70% hydration means 700 g of water per 1000 g of flour. They make recipes easy to scale up or down. Boule's calculator does this math for you: set your target weights and hydration, and it returns flour, water, levain, and salt in grams.

A common signal is that the starter has roughly doubled in the jar and holds a domed peak, usually four to eight hours after feeding. Tracking the rise between feedings makes this predictable. Boule can scan the jar with your camera and read how much the starter has risen since the last feeding, so you learn its rhythm instead of guessing.

Yes. Boule tracks several starters side by side, each with its own name, feeding cadence, and flour blend. Each one gets its own countdown and reminders, which helps when you keep, say, a white starter and a rye starter on the same counter.

Boule works entirely offline — every feature runs in airplane mode. Feedings, reminders, rise scans, baker's math, and bake notes all happen on the device with no account and no server, so a kitchen with no signal is no problem.

You point your iPhone camera at the starter jar, and Boule reads the current level to work out how much the starter has risen since the last feeding. The image processing runs on the device, and the scan is optional — the app works fully without it.

Most starters are kept at 100% hydration — equal weights of flour and water — because it is easy to maintain and to calculate recipes from. Stiffer or wetter starters are also valid choices with different fermentation characters. Boule's baker's math works in grams at whatever hydration you choose.

Work backwards from the recipe: if it calls for 20% levain in baker's percentages, that is 200 g of levain per 1000 g of flour, plus a little extra so your starter jar is never emptied. Boule's calculator handles this — enter your recipe targets and it returns the flour, water, levain, and salt weights in grams.

Yes. Boule keeps a simple bake note for each loaf — what you baked, how it went, what to change next time. Over a few bakes the notes become your own reference for timing, hydration, and proofing decisions.

No. There is no account to create and no sign-in. All data — starters, feedings, rise scans, and notes — stays on your device, and every feature works without a network connection.