General Knowledge of the Baker Trade
What this domain tests
This domain covers the calculations and controls that surround every bake: baker's percentage and formula scaling, yield and costing, temperature conversion and dough-temperature control, sanitation and allergen control, and correct equipment use. Questions are applied rather than abstract, so expect to choose a number or a corrective action.
Core rules
- Baker's percentage. Flour is always 100%; every other ingredient is a percentage of the flour weight, not of the total. The total formula percentage is the sum of all percentages and is always above 100%. To scale, divide the required total dough weight by the total percentage to obtain flour weight.
- Dough temperature. Water temperature is the main lever. For a three-factor calculation: water temperature = (desired dough temperature × 3) − (room temperature + flour temperature + friction factor). Add a preferment as a fourth factor when one is used. The friction factor is mixer-specific and must be measured, not guessed.
- Yield and costing. Trim, shrinkage and baking loss change true yield. Portion cost = ingredient cost ÷ usable portions; selling price = portion cost ÷ target food-cost percentage.
- Sanitation. Keep food out of the 4–60 °C danger zone. Cool from 60 to 20 °C within 2 hours and from 20 to 4 °C within 4 hours. Label, date and rotate stock (FIFO), and control allergen cross-contact with dedicated tools and documented cleaning.
Worked example
A lean dough formula totals 173.5%: flour 100%, water 65%, salt 2%, yeast 1.5%, sugar 2%, shortening 3%. You need 40 rolls at 55 g, so the required dough is 40 × 55 = 2,200 g. Flour weight = 2,200 ÷ 1.735 = 1,268 g. Water = 1,268 × 0.65 = 824 g; salt = 25 g; yeast = 19 g; sugar = 25 g; shortening = 38 g. Check: 1,268 + 824 + 25 + 19 + 25 + 38 = 2,199 g, the small difference being rounding.
Traps that cost marks
Treating the total dough weight as 100%; omitting the friction factor from dough-temperature math; scaling flour by volume; confusing food cost with markup; ignoring bake loss when calculating portions; and using a formula percentage as if it were a percentage of total weight.
Key points
- Flour is 100% in baker's percentage; all other ingredients are relative to flour.
- Scale by dividing desired total weight by the total formula percentage.
- Water temperature controls final dough temperature; friction factor must be measured.
- Cool foods through the danger zone in two documented stages.
- True portion cost must include trim and baking loss.