Methods of stepping up (scaling) recipes
To step up a recipe, multiply every ingredient by the conversion factor = desired yield ÷ original yield, or use the percentage method based on total weight.
What stepping up means
Stepping up (scaling up, enlarging) means increasing a tested recipe from a small yield to the large yield needed for quantity service without losing quality. The same working steps down a recipe. It is done on standardised recipes, with ingredients converted to weights (grams and kilograms), because weighing is more accurate than cups and spoons in bulk. The methods are the factor method, the percentage method, direct-reading tables (ready-made tables of quantities in quantity cookery books) and recipe software.
Factor method: lemon rice from 4 to 25 portions
A lemon rice recipe for 4 portions uses raw rice 400 g, oil 40 g, groundnuts 40 g, bengal gram dal 20 g, lemon juice 40 ml, salt 8 g and turmeric 4 g. Step it up to 25 portions.
- Conversion factor = desired yield ÷ original yield = 25 ÷ 4 = 6.25
- Raw rice = 400 g × 6.25 = 2500 g = 2.5 kg
- Oil = 40 g × 6.25 = 250 g; groundnuts = 40 g × 6.25 = 250 g
- Bengal gram dal = 20 g × 6.25 = 125 g; lemon juice = 40 ml × 6.25 = 250 ml
- Salt = 8 g × 6.25 = 50 g; turmeric = 4 g × 6.25 = 25 g
For 25 portions: rice 2.5 kg, oil 250 g, groundnuts 250 g, bengal gram dal 125 g, lemon juice 250 ml, salt 50 g, turmeric 25 g. Add the salt in two parts and taste before adding the rest.
Percentage method: carrot kosambari for an industrial canteen
A tested kosambari (salad) recipe uses grated carrot 500 g, soaked moong dal 250 g, cucumber 150 g, grated coconut 60 g, lemon juice 25 g, salt 10 g and green chilli with coriander 5 g (total 1000 g). The canteen needs 240 portions of 50 g.
- Percent of each = weight ÷ total × 100: carrot 50%, moong dal 25%, cucumber 15%, coconut 6%, lemon juice 2.5%, salt 1%, chilli and coriander 0.5% (total 100%)
- Total weight needed = 240 portions × 50 g = 12,000 g = 12 kg
- Carrot = 50% × 12 kg = 6 kg; moong dal = 25% × 12 kg = 3 kg; cucumber = 15% × 12 kg = 1.8 kg
- Coconut = 6% × 12 kg = 720 g; lemon juice = 2.5% × 12 kg = 300 g
- Salt = 1% × 12 kg = 120 g; chilli and coriander = 0.5% × 12 kg = 60 g
- Check: 6000 + 3000 + 1800 + 720 + 300 + 120 + 60 = 12,000 g
Carrot 6 kg, soaked moong dal 3 kg, cucumber 1.8 kg, coconut 720 g, lemon juice 300 g, salt 120 g, chilli and coriander 60 g. Add a small margin for handling loss if needed.
When the portion size also changes
A dal recipe gives 20 portions of 150 ml and uses 600 g toor dal. A hospital needs 120 portions of 100 ml. How much toor dal is needed?
- Original total yield = 20 × 150 ml = 3000 ml
- Desired total yield = 120 × 100 ml = 12,000 ml
- Conversion factor = 12,000 ÷ 3000 = 4
- Toor dal = 600 g × 4 = 2400 g
Factor = 4; toor dal needed = 2.4 kg. Every other ingredient is also multiplied by 4.
Precautions when stepping up
- Convert all quantities to weight first; avoid cups and spoons in bulk.
- Do not multiply salt, chilli, spices and leavening (soda, baking powder) blindly: add part, taste, then add the rest.
- Large, deep vessels lose less water by evaporation: reduce water a little and adjust.
- Cooking time does not rise in the same ratio; large batches take longer to heat and to cool.
- Step up in stages and test at each stage before the next increase.
- Check equipment capacity (boiling pan, tilting pan, mixer) and the mixing method.
- Round sensibly to quantities that can be weighed, and state how you rounded.
In your practical you step a dish up to 25 portions; in hostel or wedding catering the same factor method turns a 4-portion trial into 500 portions, keeping taste, portion size and cost under control.
2 marks: “What is a conversion factor?” Conversion factor = desired yield ÷ original yield. Every ingredient is multiplied by it to step a recipe up or down.
5 marks: “Explain the factor method of stepping up a recipe with an example.” Define the factor; work a small example (4 to 25 portions, factor 6.25) ingredient by ingredient; mention adjusting salt and spices by taste.
10 marks: “Describe the methods of stepping up recipes. What precautions should be taken?” Factor method and percentage method with worked examples, the formula when portion size changes, direct-reading tables and software, then the precautions.
New ÷ Old = Factor. Multiply everything by it, but taste-adjust the salt and spice.