Yield: definition, yield percentage and factors affecting yield
Yield is the usable amount left after cleaning, trimming and cooking. Yield % = edible portion ÷ as-purchased weight × 100; it tells you how much to buy.
What yield means
Yield is the amount of usable food obtained from a given amount of raw food. It can be stated as a weight, a volume, a number of portions or a percentage. Two weights matter: as purchased (AP), the weight bought, and edible portion (EP), what is left after cleaning, peeling, trimming or deboning. Cooking changes weight again: rice and dal gain water, while meat and vegetables lose water and fat. This cooking yield decides how many portions a batch gives.
Yield percentage and quantity to buy
A hostel buys 20 kg of cauliflower. After removing leaves and stalk, 12 kg of florets remain. (a) Find the yield %. (b) How much cauliflower must be bought to get 30 kg of florets?
- (a) Yield % = EP ÷ AP × 100 = 12 ÷ 20 × 100 = 60%
- (b) AP needed = EP needed ÷ yield fraction = 30 kg ÷ 0.60 = 50 kg
- Check: 50 kg × 0.60 = 30 kg
In this lot the yield is 60%, so 50 kg of cauliflower must be bought to get 30 kg of florets.
Cooking yield and number of portions
In this kitchen, 10 kg of raw rice gives 28 kg of cooked rice (illustrative; it varies with the rice and the method). The portion is 250 g of cooked rice. How many portions does the batch give, and how much raw rice is that per portion?
- Cooking yield = 28 kg ÷ 10 kg = 2.8 times the raw weight
- Portions = 28,000 g ÷ 250 g = 112
- Raw rice per portion = 10,000 g ÷ 112 = 89.3 g, about 89 g (rounded to the nearest gram)
112 portions of 250 g; each uses about 89 g of raw rice.
Factors affecting yield
| Factor | Effect on yield | Example |
|---|---|---|
| Quality and freshness | Fresh, good-grade food wastes less | Firm cabbage vs one with wilted outer leaves |
| Size and maturity | Very small or over-mature produce wastes more | Small potatoes lose more in peeling |
| Market form | Cleaned or portioned forms give near-complete yield | Boneless chicken vs a whole bird |
| Pre-preparation method | Thick peeling and careless trimming cut yield | Peeling carrots thinly vs chopping off the ends generously |
| Staff skill and tools | Trained cooks with sharp, correct tools trim less | Filleting fish neatly |
| Cooking method, time and temperature | Overcooking and high heat increase moisture and fat loss | Chicken roasted at too high a heat shrinks more |
| Holding time | Long holding dries food and leaves more unusable | Dried-out rice at the edge of a bain-marie pan |
| Storage conditions | Poor storage causes wilting and spoilage | Greens kept warm overnight |
| Portion control | Accurate serving gives the planned number of portions | Standard ladle for dal |
How to improve yield
- Buy the right grade, size and market form for the use.
- Use standard pre-preparation methods and train staff.
- Keep knives sharp and use the right cutters and peelers.
- Cook at the correct temperature and time; cook in batches close to service.
- Use trimmings: bones for stock, vegetable trimmings for soup, ridge gourd peel for thogayal.
In a hospital diet kitchen, nutrients are planned on the edible portion, so knowing the yield of each vegetable and dal ensures the patient's plate carries the planned amount.
2 marks: “Define yield.” Yield is the usable amount of food obtained from a given amount of raw food after cleaning, trimming or cooking; yield % = EP ÷ AP × 100.
5 marks: “What are the factors affecting yield? Explain with examples.” Quality, size and maturity, market form, pre-preparation method, staff skill and tools, cooking method and temperature, holding time, storage and portion control.
Buy = Need ÷ Yield. AP is what you pay for; EP is what you eat.