Unit conversion

Unit conversion is scaling a weighed formula. It is not a table of “one cup of flour equals…” estimates, because packing and moisture change volume. Weighing first.

Percent from pounds #

King Arthur: flour is 100%; divide each ingredient’s weight by flour weight and multiply by 100. Their straight white bread: 50 lb flour, 33 lb water, 1 lb salt, 0.6 lb yeast → 100%, 66%, 2%, 1.2% ¹. Hydration is that liquid percent.

To go the other way, turn each percent into a decimal and multiply by the flour you actually have. Their ciabatta sketch at 50 lb flour and 73% water is 36.5 lb water ¹.

Scaling the whole dough #

When you need a different batch size, add the percents, divide the new dough weight by that sum, and multiply each percent by that conversion factor. King Arthur’s French-bread example: 168.25% total, 150 lb wanted → factor about 0.89, which they round up to 0.9 so they bake a little extra rather than short ¹.

Preferments: either treat the preferment as one ingredient, or split it into flour and water and restate overall baker’s percent so salt does not look like 3% when half the flour was already in the poolish ¹.

Match units to the formula #

Convert ounces to grams with the scale’s unit switch or a trusted conversion. Jam uses a different measurement contract from baker’s percent. The teaching loaf that already lives in mass is Country loaf (teaching formula). Mise en place is doing this math before the mixer, not during it.