It’s not a recipe.

Flour.Water.Salt.

That’s the whole ingredient list.The rest of the book is about what you do with them.

“Learn this system, and you will never need a bread recipe again.”
— From Foreword — A Word on the Word “Opinionated” in The Sourdough Formula
A golden sourdough boule with a deeply opened score, centered on a wooden bread board.
Front cover of The Op!nionated Baker’s Sourdough Formula by Danny Kosarin: a golden sourdough boule on a wooden board against deep slate, with the subtitle “What Everyone Gets Wrong About Sourdough Bread … and Why It’s Not a Recipe!” and the loaf’s formula in the corner.

The book

The Sourdough Formula

What Everyone Gets Wrong About Sourdough Bread … and Why It’s Not a Recipe!

by Danny Kosarin

The Sourdough Formula is not a recipe collection. It is one system, built on baker's percentages and decades of obsessive practice, that teaches you what your dough is doing and why, so you can stop following instructions and start making your own calls. It is opinionated on purpose: it tells you exactly where to start, what to master first, and what to ignore until you have earned the complications.

From The Sourdough Formula, coming December 2026.

“The same system describes any variation you can imagine and gives you an almost secret language by which you can tell others what you baked. I could, for instance, tell you I made an 80% hydration whole grain Red Turkey boule with 15% inoculation and 2% salt, and you could make it at any scale without another word of instruction.”
— From Foreword — A Word on the Word “Opinionated” in The Sourdough Formula
Back cover of The Sourdough Formula: “There are a lot of ways to make bread. This is mine.” followed by the back-cover pitch, Danny Kosarin’s author photo and bio, and the ISBN barcode, over the same boule and slate background.
The back of the book.

Foreword — A Word on the Word “Opinionated”

“If you don’t want to read about flour and mills and gluten and enzymes, and instead just want to know how to bake a decent, edible loaf—well, I’m afraid you may have come to the wrong place.

This book contains far more information than is strictly necessary to bake good bread. That’s not just because I promised you an opinionated book. It’s also because I’m a nerd. This book is the direct result of how I think about, acquire, and process information—and how I learned to be a very good baker.”

— From The Sourdough Formula

What's inside

Nine chapters, one system

  1. 01The Opinionated Baker, Who He Is and Why You Should CareWhy I bake the way I do, where these opinions came from, and why I ask you to trust them.
  2. 02Flour and the Joys of GlutenHow wheat, milling, protein, and extraction determine the dough you can make and the bread it can become.
  3. 03The Baker’s Percentage (It’s a Formula, Not a Recipe!)How baker's math lets you understand a bread, change it deliberately, and make as much or as little of it as you want.
  4. 04Sourdough Starter, Levain, and FermentationHow to maintain a culture, build the levain a bake requires, and recognize what fermentation is actually doing.
  5. 05The Process—Bake Day and Your First BreadHow mixing, strengthening, fermentation, and time turn a formula into dough — and how shaping, cold proof, and the right bake environment turn that dough into bread.
  6. 06Reading and Troubleshooting the Finished LoafHow crust, shape, ear, crumb, texture, and flavor reveal what happened throughout the bake — and how to work backward from the loaf to decide what to change next time.
  7. 07A Few Formulas (That Aren’t Recipes)Adaptable starting structures for lean hearth breads, country loaves, and pan breads — plus where inclusions and enrichments enter the formula — built to be understood rather than merely followed.
  8. 08Tools and SetupWhat genuinely helps, what you can do without, and how to build a kitchen that supports the way you bake.
  9. 09So, are you ready to start walking?What it means to give someone a loaf, and where your baking goes once the system becomes your own.

Plus a front-matter guide to the Bread Lab companion app.

A sourdough boule with flour-dusted scoring on a wooden cutting board.
“Another one I swear by: Start with hearth breads. These are the free-formed, traditionally shaped loaves—the boules and bâtards and baguettes, baked on a stone, a steel, or in a Dutch oven, their shapes held aloft by structural strength alone, the skin tightened like a ball of mozzarella. Hearth breads are the best place to start not because they’re easiest (they’re not), but because their failures will teach you far more than your successes. Loaf pans and other forms forgive far too many sins for you to learn anything useful from them.”
— From The Sourdough Formula