Sourdough Companion: Baker's Percentage Calculator

Sourdough Companion is a local baking app that does the arithmetic behind a sourdough loaf. Pick a familiar bread preset or enter your own baker's percentages, set the dough weight you want, and it gives you exact amounts of flour, water, starter, and salt — then walks you through a simple fermentation and baking checklist.

What it does

Presets or your own formula. Start from a familiar bread preset, or type in the percentages from a recipe you already trust.

Scales to the dough you want. Set a target dough weight and the whole formula scales to it — useful when a recipe makes one loaf and you want three, or when your banneton is smaller than the author's.

Exact ingredient amounts. Flour, water, starter, and salt, calculated for your target, so there's no mental maths with sticky hands.

A bake-day checklist. A simple sequence for fermentation and baking, so you're not scrolling back through a recipe to find the next step.

Planning, kept separate from judgement. The app is clear that its numbers and checklist are planning help. Whether a dough is ready, or a starter is healthy, is still your call.

How baker's percentages work

Serious bread recipes are written in baker's percentages: every ingredient is a percentage of the total flour weight, and the flour is always 100%. The format is why sourdough recipes scale so cleanly — and why a calculator helps.

Take a common starting point: 75% water (the hydration), 20% starter, and 2% salt. Add them to the flour's 100% and the whole dough is 197% of the flour weight. So for a 900 g dough:

• Flour: 900 ÷ 1.97 ≈ 457 g
• Water: 75% of 457 ≈ 343 g
• Starter: 20% of 457 ≈ 91 g
• Salt: 2% of 457 ≈ 9 g

Change the target weight and every amount moves together. Change the hydration and you know exactly what changed. That's the whole appeal: you adjust the recipe, not the arithmetic.

One thing to watch when comparing recipes: some bakers also count the flour and water inside the starter when they quote hydration, which gives a slightly higher effective figure. Check which convention a recipe uses before copying its numbers. (The example above is our illustration of the method, not a formula taken from the app.)

What it won't do

• judge food safety — whether a dough, starter, or finished loaf is safe is your judgement, not the app's
• store your recipes in an account or the cloud — calculations stay on your device

How it differs from Levain

The original is Levain, a mobile web app for sourdough bakers.

Sourdough Companion is the focused version: the calculator and the checklist. If you want recipes for pizza, rye, and pancakes, or help diagnosing a flat loaf, the original has more ground covered and is free to open at levain.pages.dev.

When to reach for it

• You're scaling a recipe up for a crowd or down for one loaf
• A recipe is written in percentages and you need weights
• You want to try a higher-hydration dough without redoing the maths
• You're baking several loaves of different sizes on the same day
• You want the steps in front of you while your hands are covered in dough

What's actually inside

One app. Calculations run locally, with no account and no connection to any service.

Setting it up

The GitHub route (the original). Levain runs in any browser at its own address. To run it yourself, clone the repository, run npm install, then npm run dev — it's a React app built with Vite.

To be fair to the original: it's already easy to open in a browser. What Sourdough Companion offers is the calculator and checklist as a focused local app inside your Taku workspace.

The Taku route. Open Sourdough Companion in Taku and enter your formula.

Who made it

Levain was built by S. Beygi and released under the MIT license. Its README credits Hendrik's open-source The Sourdough Framework as its main inspiration — a rigorous, science-based guide worth reading if you want to go deeper. Sourdough Companion was published to the Taku marketplace by S. Beygi.

You don't need to be technical to use this

You don't need to understand GitHub, Codex, or Claude Code to use this app. Plenty of useful tools start life as a code repository, and nobody should have to learn one to calculate how much water goes into their dough.

Taku is a desktop app built for that: find something useful someone already made, open it in your own workspace, and use it with no setup. Browse the free app library for more everyday tools, or read why most AI tools end up in your bookmarks for the setup problem Taku is built around. If you'd rather burn off the bread, the 7-Minute Workout app times a bodyweight session for you.

Download Taku and plan your next bake. Taku is in Beta, and the Mac app is available now; there's also an experimental, unsigned Windows build for Windows 10 and 11.

FAQ

What does Sourdough Companion do?

It lets you choose a bread preset or enter baker's percentages, scales the formula to a target dough weight, shows exact flour, water, starter, and salt amounts, and gives you a fermentation and baking checklist.

What are baker's percentages?

A way of writing recipes where every ingredient is a percentage of the flour weight, with flour at 100%. It makes recipes easy to scale and compare.

Does it tell me if my dough or starter is safe?

No. It separates planning help from food-safety judgement, which stays with you.

Is it the same as Levain?

No. It's adapted from Levain but focuses on the formula calculator and bake-day checklist. Levain also includes pizza calculations, recipes, a baking guide, and a troubleshooter.

Is it free?

The app is free in the marketplace. For what Taku itself costs, see pricing.

Key points

• Scales a sourdough formula to any target dough weight.
• Works from presets or your own baker's percentages.
• Gives exact flour, water, starter, and salt amounts, plus a bake-day checklist.
• Calculations stay local; food-safety judgement stays with you.
• Adapted from the Levain web app, focused on the calculator and checklist.