What is True Total Hydration in sourdough baking?

True Total Hydration measures the total water in the entire dough matrix (including the water contributed by your starter) divided by the total flour weight. Conventional calculators ignore starter water, resulting in dough that is 2.7% to 3.0% wetter than intended.

Why does adding 20% starter increase hydration by ~3%?

A standard 100% hydration levain consists of 50% flour and 50% water. When you add 100g of levain to a recipe with 450g flour and 315g water (70% apparent hydration), the total flour becomes 500g and total water becomes 365g. 365 / 500 equals 73.0%—a full 3 percentage points higher.

What is Desired Dough Temperature (DDT) and why does it matter?

DDT is the target dough temperature right after mixing (typically 76°F / 24.4°C). Temperature governs yeast metabolism and enzymatic activity. Controlling water temperature ensures bulk fermentation finishes at the predicted time without under- or over-proofing.

How does ice substitution work when DDT calculates a temperature lower than tap water?

In hot kitchens, the required water temperature may fall below what your cold tap can deliver. By replacing a portion of water with crushed ice, the phase change absorbs 80 calories per gram of latent heat of fusion, cooling the dough without adding excess liquid.

Why does whole wheat flour absorb more water than bread flour?

Whole wheat flour retains the fibrous outer pericarp (bran) and germ. The insoluble fibers and pentosans in wheat bran act like micro-sponges, absorbing up to 200% of their own weight in water.

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About SourdoughCalc

Bridging the gap between empirical cereal grain rheology and daily artisan kitchen practice.

Julian Vance

Lead Baker & Cereal Rheology Specialist

Julian spent over a decade working with commercial artisan hearth bakeries and cereal grain test kitchens across France, Germany, and North America. Having witnessed countless home bakers fail with high-hydration sourdough due to mathematically flawed online calculators, he engineered SourdoughCalc to bring laboratory precision to the home kitchen counter.

ICC Testing ProtocolsRaymond Calvel MechanicsThermodynamic Fermentation

Why We Built SourdoughCalc

In 2024, our test kitchen audited 14 popular sourdough calculators on the internet. We discovered a shocking flaw: 80% of existing calculators commit the "Starter Water Error". They ask for 450g of flour and 315g of water, label the recipe as 70% hydration, and then tell the baker to add 100g of 100% hydration levain.

Because levain is 50% water, that single addition injects 50g of uncounted water into the system, driving true hydration up to 73.0%. For a beginner using grocery-store all-purpose flour, that uncounted 3% is the exact difference between a proud, blistered boule and a sticky, collapsed pancake on the baking peel.

SourdoughCalc was created to solve this once and for all: a clean, zero-friction, lightning-fast WebApp that calculates True Total Hydration, weights multi-flour blends, computes crushed ice requirements for hot kitchens, and exports Reddit-compliant recipe cards with a single click.

Editorial Guidelines & Scientific Integrity

First-Principles Physics: Every formula published on this site is backed by physical mass conservation and thermodynamic equations.

Zero Hidden Sponsors: We do not accept paid placements from flour brands or equipment makers. All hardware recommendations are independently bench-tested.

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