The Four Ingredients — Deep Dive

Flour: the structure

Flour is arguably the most important ingredient in baking. As the single largest component in most bread recipes, it should be given the same careful consideration a chef gives to choosing a star ingredient in a recipe. At this moment, we’re in a lucky position: Small, local mills are springing up all over, and ordering flour and grain online couldn’t be easier. For a home baker keen on experimentation, this means al

When flour meets water, proteins (glutenin and gliadin) combine to form gluten — an elastic network that traps CO2 gas from fermentation. Malleable gliadin gives the dough its ability to expand, while glutenin is responsible for elasticity and strength.

Flour types and when to use them

White flour (~11.5% protein): The workhorse for most sourdough loaves. King Arthur All-Purpose or Central Milling Artisan Baker's Craft.

High-protein bread flour (~12.7-14%): Use when you need extra structure — enriched doughs, loaves with lots of inclusions, bagels.

Whole wheat: Higher protein (13-14%), more bran and germ. Absorbs more water, ferments faster, produces a tighter crumb with dramatically increased flavor and nutrition.

Type-85 / high-extraction: Between white and whole wheat — ample flavor and nutrition, but still produces light and airy loaves. If you can't find it, mix 65% white flour with 35% whole wheat.

Rye: Incredibly flavorful even in small percentages. Doesn't form the same gluten network as wheat — dough will be sticky. Ferments faster than white flour.

Water: the activator

Water activates gluten formation and dissolves salt. Hydration — water as a percentage of flour weight — controls dough texture. Lower hydration means a stiffer, easier-to-handle dough. Higher hydration means a more open crumb, but harder to shape.

If your water is safe to drink, it will work well for baking. The most important thing about water is its temperature: this is how you control dough temperature, which in turn controls how fast fermentation happens.

Salt: the regulator

Salt is added in a small percentage — typically 1.8-2% of flour weight — but its impact is enormous. It strengthens gluten, slows fermentation, enlivens the flavor of other ingredients, and helps preserve color and flavor by reducing oxidation.

Without salt, bread tastes flat and the dough is slack and sticky. Too much salt kills the yeast. Always measure salt by weight. Fine sea salt is the best choice for baking.

Starter: the leavening

A sourdough starter is a mixture of flour and water that hosts a stable blend of beneficial bacteria and wild yeasts. This mixture is continually maintained with regular refreshments (or feedings) and is used to leaven and flavor new dough. The starter is the basis for natural fermentation, and learning how to best care for and use one is the key to successful sourdough bread baking.

The key variable is activity. Use your starter at peak: doubled in size, domed on top, full of bubbles. A sluggish starter means slow, incomplete fermentation. A starter that's past peak is too acidic and will weaken the dough structure.