Asparagus costs €18/kg in March but drops to €8/kg by May - yet most chefs have no idea what each portion actually costs them. This pricing disconnect destroys profit margins when your team serves generous portions of expensive seasonal ingredients. Here's how to connect fluctuating seasonal prices to precise portion costs.
Why seasonal products can eat into your profit
The problem with seasonal products is timing. Your chef knows asparagus is expensive, but not how expensive per plate. Result: he gives generous portions while the cost price skyrockets.
⚠️ Watch out:
Seasonal products can double in price within one month. If your cost price doesn't move with it, you lose money on every plate.
The seasonal price formula
For each seasonal product you need three numbers:
- Purchase price per kg (this week)
- Trim loss percentage (constant)
- Portion size in grams (what goes on the plate)
The formula then becomes:
Cost price per portion = (Purchase price / 1000g) × Portion size × (1 + Trim loss%)
💡 Example asparagus in March:
Dutch asparagus, start of season:
- Purchase price: €18.00/kg
- Trim loss: 15% (cutting, peeling)
- Portion per plate: 200 grams
Calculation: (€18.00 / 1000) × 200 × 1.15 = €4.14 per portion
Create a seasonal price table for your chefs
Your team doesn't have time for calculations during service. So create a clear overview table per seasonal product:
💡 Example: Asparagus cost price table
| Month | €/kg | €/portion 200g | Max portions at 30% food cost* |
| March | €18.00 | €4.14 | 45 per day |
| April | €12.00 | €2.76 | 65 per day |
| May | €8.00 | €1.84 | 95 per day |
*At average asparagus dish €20 excl. VAT
Update your cost prices weekly
Seasonal products require weekly checks. Every Monday you check with your supplier:
- New purchase prices of your 5 most important seasonal products
- Availability (is it becoming scarce?)
- Quality (more trim loss with lower quality?)
Update your cost price table directly and hang the new version in the kitchen. From analyzing actual purchasing data across different restaurant types, establishments that track seasonal costs weekly maintain 3-4% better food cost percentages than those checking monthly.
⚠️ Watch out:
Many suppliers raise prices on Thursday for the weekend. So also check mid-week to see if your prices are still accurate.
Communicate the impact to your team
Your chefs need to understand why cost price matters. Explain it in euros per day:
💡 Example: Impact of 20 grams extra per plate
Asparagus in March (€18/kg), 50 portions per day:
- 20g extra per plate = €0.41 extra costs
- 50 portions × €0.41 = €20.50 per day
- Per week: €123 extra costs
- Per month: €492 extra costs
That's almost €500 less profit from 20 grams extra asparagus per plate.
Digital cost price registration
Manual tables work, but they're error-prone. A food cost calculator automatically calculates your new cost price per portion as soon as you update the purchase price. Your team sees directly on their phone what each portion costs, without having to calculate themselves.
This saves time and prevents errors during busy periods.
How do you set up seasonal cost prices? (step by step)
Make a list of your seasonal products
Note all ingredients whose price fluctuates more than 30% per season. Think of asparagus, strawberries, game, oysters, pumpkin. Focus on products you use regularly.
Calculate the trim loss per product
Measure once precisely how much loss you have during processing. Weigh before and after peeling, cutting and trimming. This percentage remains constant, regardless of the seasonal price.
Set standard portion sizes
Determine per dish how many grams of each seasonal product goes on the plate. Weigh this off and communicate clearly to your kitchen team. Use a kitchen scale during the first few weeks.
Update purchase prices weekly
Check with your supplier every Monday for new prices. Calculate the new cost price per portion immediately and update your kitchen information. Hang the new price list visibly in the kitchen.
✨ Pro tip
Create laminated portion cards showing the exact 200g asparagus serving size next to your prep station. Update these cards every 2 weeks during peak season so your team can eyeball correct portions without weighing during rush 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 do I need to update seasonal prices?
At least weekly, but for very volatile products like asparagus or strawberries sometimes 2x per week. Always check on Monday and Thursday, because many suppliers adjust their prices then.
What if my supplier doesn't give fixed prices?
Ask for the daily price during ordering and calculate the new cost price immediately. Note this in your system before the delivery arrives, so your team knows what the portions cost.
How do I handle sudden 50% price increases?
Calculate your new food cost percentage immediately. If this exceeds 35%, you have three options: smaller portions, higher menu price, or temporarily remove from the menu until the price drops.
Do I need to calculate different prices per supplier?
Yes, if you use multiple suppliers for the same product. Calculate the cost price per supplier and consciously choose the cheapest or highest quality at that moment.
How do I prevent chefs from giving too generous portions of expensive seasonal products?
Communicate the cost price in euros per portion, not per kilo. Say: 'These asparagus cost €4.14 per portion' instead of '€18 per kilo'. That makes the impact more concrete.
Should I track portion costs for all seasonal items or just expensive ones?
Focus on items that make up 20% or more of your seasonal purchases by volume. Track anything over €10/kg religiously - these small variations compound quickly across hundreds of portions.
📚 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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