A beach restaurant hired three seasonal servers last summer and watched their food costs mysteriously climb from 28% to 34% within weeks. The culprit? Oversized portions from well-meaning staff who'd rather give too much than face complaints. Here's how to calculate exactly what those generous servings cost you.
Why seasonal staff ends up costing more
Seasonal workers operate under pressure and prioritize guest satisfaction above all else. Without clear portion guidelines, they'll consistently err on the side of generosity. That extra spoonful of sauce, additional slice of meat, or heaping side of pasta seems insignificant in the moment—but it devastates your margins.
⚠️ Watch out:
Seasonal staff rarely ask for clarification on portions. They'd rather guess generously than risk customer complaints or appear inexperienced.
First, measure your current deviations
You can't fix what you don't measure. Track actual portions served by seasonal staff against your standards for one full week.
- Weigh 20 random plates per dish
- Compare against your standard portion
- Calculate average difference in grams
- Focus on your 5 top-selling dishes
💡 Example measurement:
Steak standard: 200 grams
- Measured with seasonal staff: 235 grams
- Deviation: +35 grams (+17.5%)
- Steak costs €24/kg = €0.024 per gram
- Extra cost per portion: 35 × €0.024 = €0.84
Calculate the financial impact per dish
Apply this formula to determine extra cost per portion:
Extra cost = (Actual portion - Standard portion) × Purchase price per gram
Calculate this for each main ingredient showing deviations. Pay special attention to expensive components: meat, fish, aged cheese, premium nuts. I've seen restaurants lose €200-400 monthly just from uncontrolled protein portions—a mistake that's completely avoidable with proper measurement.
💡 Example calculation pasta:
Pasta carbonara - deviations with seasonal staff:
- Pancetta: +15g × €0.032/g = €0.48
- Parmesan: +8g × €0.028/g = €0.22
- Pasta: +25g × €0.003/g = €0.08
Total extra per portion: €0.78
Calculate what this costs per season
Multiply extra cost per portion by portions served during seasonal staff employment. Don't calculate for the entire year—only their actual working period.
Seasonal costs = Extra per portion × Portions per day × Working days seasonal staff
💡 Example beach bar (3 months summer):
Steak extra cost: €0.84 per portion
- Sales: 25 steaks per day
- Working days: 90 days (3 months)
- Seasonal costs: €0.84 × 25 × 90 = €1,890
For one dish alone, nearly €2,000 in extra costs!
Add up all dishes
Run this calculation for every main dish showing deviations. Sum the total extra costs to reveal your true seasonal damage.
- Focus on your 5-8 best-selling dishes
- Calculate only main ingredients (meat, fish, cheese)
- Include expensive side dishes
- Sum everything for total seasonal damage
⚠️ Watch out:
Calculate only for seasonal staff working periods. If they work 4 months, don't extrapolate to a full year.
Compare with the cost of training
Now you know what sloppy portioning costs, compare this against training and portion tool investments. Proper portion training typically pays for itself within 2-3 weeks.
- Portion spoons and bowls: €50-€150
- Training time: 2 hours per person × €15/hour = €30
- Laminated portion cards: €20
- Total investment: approximately €200-€300
If your seasonal damage exceeds €2,000, you'll recover this investment easily.
How do you calculate the extra costs? (step by step)
Measure the actual portions
Weigh 20 random plates per dish over the course of a week. Compare with your standard portion and calculate the average difference in grams. Focus on your 5 best-selling dishes.
Calculate extra cost per portion
Use the formula: (Actual portion - Standard portion) × Purchase price per gram. Do this for each main ingredient where you see deviations.
Calculate what this costs per season
Multiply extra cost per portion × portions per day × working days seasonal staff. Add up all dishes for your total seasonal damage.
✨ Pro tip
Weigh portions during your first 3 days of seasonal operations, then again at day 14. Staff who start precise often become generous within two weeks—catching this early prevents months of inflated costs.
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
Which dishes should I measure with seasonal staff?
Focus on your 5 best-selling dishes containing expensive main ingredients like meat, fish, or cheese. These create the biggest impact on your food cost. Skip measuring basic sides like bread or simple salads.
How often should I check portions during the season?
Sample 10-15 plates weekly throughout the season. Seasonal staff portions tend to grow progressively larger without consistent monitoring. Weekly checks catch portion creep before it becomes expensive.
What's a normal deviation with untrained staff?
Untrained staff typically serve 15-25% oversized portions on expensive ingredients. This translates to 5-8 percentage point increases in overall food cost. Even experienced staff can drift 5-10% without portion tools.
📚 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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