Yield testing reveals exactly how much usable product remains after processing raw ingredients. Most kitchens guess at these numbers, leading to wildly inaccurate food cost calculations. Here's how to properly document yield test results and integrate them into your recipe costing.
What is a yield test and why is it important?
A yield test measures the gap between what you purchase and what you actually use after trimming, cleaning, and processing. Take a 2 kg whole salmon - after filleting, you're left with 1.1 kg of usable fillet. That missing 0.9 kg represents your trim loss.
This dramatically impacts your true food costs. You might pay €18/kg for whole salmon, but your actual fillet cost jumps to €32.73/kg.
💡 Example yield test:
Processing whole salmon:
- Purchase weight: 2.0 kg
- Fillet after processing: 1.1 kg
- Trim loss: 0.9 kg (45%)
- Yield: 55%
Actual fillet price: €18.00 ÷ 0.55 = €32.73/kg
How do you perform a yield test?
Run the same test at least 3 times per product. Every delivery batch can vary, and you need that average for accuracy.
- Weigh the raw product - include any packaging that affects weight
- Process normally - don't be extra careful just because you're testing
- Weigh the final result - only what actually goes into your dishes
- Document everything - date, supplier, product condition
⚠️ Note:
Don't just test on perfect days. Run tests during busy rushes and with different staff members. That's how you get realistic numbers.
Registering yield test results
Build a database for each product containing this essential information:
- Product and supplier - yields vary significantly between vendors
- Test data - minimum 3 separate measurements
- Average yield percentage - your recipe calculation baseline
- True cost per kilo - purchase price adjusted for yield loss
- Last update date - yields shift over time
💡 Example registration:
Salmon - Supplier A:
- Test 1: 52% yield
- Test 2: 58% yield
- Test 3: 55% yield
- Average: 55% yield
Use in recipe: €32.73/kg (€18.00 ÷ 0.55)
Using yield results in recipes
Always calculate recipes using your true cost per kilo, not the invoice price. This prevents dangerous underpricing of menu items.
Formula for actual price per kilo:
True price = Purchase price ÷ (Yield % ÷ 100)
So that salmon fillet: €18.00 ÷ 0.55 = €32.73 per kg of usable product.
💡 Example in recipe:
Grilled salmon (1 portion):
- Salmon fillet: 180 grams × €32.73/kg = €5.89
- Vegetables: €1.20
- Sauce: €0.80
- Garnish: €0.45
Total food cost: €8.34 per portion
Retesting schedule
After managing kitchen operations for nearly a decade, I've learned that yields fluctuate based on seasons, suppliers, and staff skill levels. Retest in these situations:
- New supplier - quality standards differ dramatically
- Seasonal changes - particularly crucial for seafood and produce
- Staff changes - knife skills vary between cooks
- Unusual waste patterns - if trim loss suddenly increases or decreases
Schedule comprehensive retesting of your top 20 ingredients twice yearly for optimal accuracy.
Digital vs manual tracking
Most kitchens rely on Excel spreadsheets or handwritten logs. The problem? You're manually calculating true costs for every recipe. And if purchase prices change, you're updating dozens of recipes individually.
Tools like KitchenNmbrs let you register yield percentages once per ingredient. The system automatically calculates true costs across all recipes. Update one purchase price, and every affected recipe adjusts instantly.
How do you perform a yield test? (step by step)
Weigh the raw product
Weigh the product as you receive it from the supplier. Including any packaging you throw away. Note the exact weight and the supplier.
Process the product normally
Prepare the product as you always do. No extra care because you're testing. Throw away all unusable parts (bones, skin, peels).
Weigh the end result
Weigh only what you actually use in recipes. Calculate the yield: (end weight ÷ start weight) × 100. Repeat this at least 3 times for a reliable average.
✨ Pro tip
Test yields during your busiest service periods over a 2-week span. Rush conditions reveal your true operational yields better than careful prep work during slow periods.
Calculate this yourself?
In the KitchenNmbrs app you can do this in just a few clicks. 7 days free, no credit card.
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Frequently asked questions
How often should I repeat yield tests?
Test at least 3 times per product for reliable averages. Retest with new suppliers, seasonal changes, or if you notice unusual waste patterns in your prep.
Do I need to yield test all ingredients?
Focus on expensive items requiring significant processing - proteins, fresh produce, and specialty ingredients. Skip items like pasta or rice that have minimal prep loss.
What if my yield differs greatly from industry standards?
Industry figures are starting points only. Your actual yields depend on supplier quality, seasonal variations, and prep techniques. Always use your own test results for accurate costing.
How do I factor yield loss into my menu pricing?
Calculate using true cost per kilo (purchase price ÷ yield percentage) in all recipe costs. If yield is 60%, divide purchase price by 0.60 for your actual ingredient cost.
Can I use yield percentages from online sources?
Online figures provide useful baselines, but every kitchen operates differently. Your supplier relationships, seasonal timing, and prep methods create unique yield patterns that require individual testing.
Should I test yields differently for expensive vs. cheap ingredients?
Yes - expensive proteins need multiple tests across different deliveries and seasons. Cheaper items like onions or carrots can be tested less frequently, maybe twice yearly.
📚 Sources consulted
- EU Verordening 852/2004 — Levensmiddelenhygiëne (2004) — Official source
- EU Verordening 853/2004 — Hygiënevoorschriften voor levensmiddelen van dierlijke oorsprong (2004) — Official source
- EU Verordening 1169/2011 — Voedselinformatie aan consumenten (2011) — Official source
- NVWA — Hygiënecode voor de horeca (2024) — Official source
- NVWA — Allergenen in voedsel (2024) — Official source
- Codex Alimentarius — International Food Standards (2024) — Official source
- FSA — Safer food, better business (HACCP) (2024) — Official source
- BVL — Lebensmittelhygiene (HACCP) (2024) — Official source
- Warenwetbesluit Bereiding en behandeling van levensmiddelen (2024) — Official source
- WHO — Foodborne diseases estimates (2024) — Official source
Food Standards Agency (FSA) — https://www.food.gov.uk
The HACCP standards shown in this application are for informational purposes only. KitchenNmbrs does not guarantee that displayed values are current or complete. Always consult the FSA or your local authority for the latest regulations.
Written by
Jeffrey Smit
Founder & CEO of KitchenNmbrs
Jeffrey Smit built KitchenNmbrs from 8 years of hands-on experience as kitchen manager at 1NUL8 Group in Rotterdam. His mission: give every restaurant owner control over food cost.
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