Most chefs think they know their vegetable costs - but they're calculating with phantom savings. That €1.20 onion actually runs you €1.35 per usable kilo after peeling. With pricier vegetables like asparagus, you're looking at 40% hidden markup on your purchase price.
What is weight loss with vegetables?
Weight loss represents the gap between what you purchase and what actually hits the plate. Vegetables shed weight through several channels:
- Peeling and trimming: skin from carrots, onions, potatoes
- Unusable parts: broccoli stems, outer cabbage leaves
- Dehydration: vegetables lose moisture during storage
- Damaged parts: brown spots, soft parts that need to be cut away
⚠️ Attention:
Many kitchens calculate with the purchase price but forget about weight loss. This makes your food cost appear lower than it actually is.
The formula for weight loss
You'll need two calculations to nail down your real costs:
Step 1: Calculate the loss percentage
Loss percentage = ((Purchase weight - Usable weight) / Purchase weight) × 100
Step 2: Calculate the actual price per kilo
Actual price per kilo = Purchase price / (Yield / 100)
Where: Yield = 100% - Loss percentage
💡 Example: Peeling onions
You buy 5 kg of onions for €1.20/kg. After peeling you have 4.5 kg of usable onion.
- Purchase weight: 5 kg
- Usable weight: 4.5 kg
- Loss: 0.5 kg (10%)
- Yield: 90%
Actual price per kilo: €1.20 / 0.90 = €1.33/kg
Typical weight loss per vegetable
These percentages serve as starting points. Your actual loss varies with season, quality, and prep technique:
- Onions: 8-12% (skin only)
- Carrots: 15-20% (skin and tops)
- Potatoes: 18-25% (skin and eyes)
- Broccoli: 35-45% (thick stem and leaves)
- Cauliflower: 40-50% (leaves and stem)
- Asparagus: 30-40% (woody ends)
- Leeks: 25-35% (green parts and roots)
- Lettuce: 10-20% (outer leaves)
💡 Example: Preparing asparagus
You buy 2 kg of asparagus for €8.00/kg. After trimming you have 1.3 kg of usable asparagus.
- Loss percentage: ((2.0 - 1.3) / 2.0) × 100 = 35%
- Yield: 65%
- Actual price: €8.00 / 0.65 = €12.31/kg
So your asparagus costs €12.31/kg, not €8.00/kg!
Impact on your cost price
Weight loss directly hammers your food cost margins. Skip this calculation and you're working with artificially low ingredient costs that'll sink your profits.
💡 Example: Impact on a vegetable plate
Vegetable plate with different vegetables:
- 200g carrots: €1.80/kg → €2.12/kg after loss = €0.42
- 150g broccoli: €2.50/kg → €4.17/kg after loss = €0.63
- 100g onion: €1.20/kg → €1.33/kg after loss = €0.13
Without loss: €0.36 + €0.38 + €0.12 = €0.86
With loss: €0.42 + €0.63 + €0.13 = €1.18
Difference: €0.32 per portion = 37% more expensive!
How do you minimize weight loss?
After managing kitchen operations for nearly a decade, I've learned you can reduce weight loss but never eliminate it completely:
- Buy pre-prepared: peeled carrots, sliced leeks cost more per kilo but have no loss
- Use leftovers: broccoli stem for soup, peels for stock
- Better knife skills: thinner peels, less waste
- Proper storage: less dehydration and spoilage
⚠️ Attention:
Pre-prepared product often costs 40-60% more per kilo but has 0% loss. Calculate what's more cost-effective for your kitchen.
Tracking losses digitally
Manually tracking weight loss per vegetable eats up valuable time. Food cost calculators let you set average loss percentages per ingredient. The system then automatically calculates actual cost prices for your recipes.
This prevents you from unknowingly using food costs that are too low and losing money on your dishes.
How do you calculate weight loss with vegetables?
Measure the purchase weight
Weigh the vegetables as you've purchased them, including skin, stem, and unusable parts. Note this weight as your starting point.
Prepare the vegetables
Peel, cut, and remove all unusable parts as normal. Then weigh the usable product that you can actually use in your dishes.
Calculate the loss percentage
Use the formula: ((Purchase weight - Usable weight) / Purchase weight) × 100. This gives you the percentage you lose during preparation.
Calculate the actual cost price
Divide your purchase price by the yield (100% - loss percentage). This is the real price per kilo of usable product you should use in your cost price calculation.
✨ Pro tip
Track weight loss for your top 3 vegetables over the next 2 weeks - these usually represent 60% of your vegetable spend. Measure before and after prep to get your baseline loss percentages.
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
Do I need to measure weight loss again with each delivery?
No, measure it a few times per season per vegetable. The loss percentage stays fairly consistent unless your supplier or season changes significantly.
Can I estimate the loss percentage instead of measuring?
That's inaccurate and costs you money. A difference of 5% loss means at least 50 cents extra per kilo actual cost price with expensive vegetables.
What do I do with vegetables that I use both peeled and unpeeled?
Calculate two different cost prices: one for peeled use and one for unpeeled. Use the correct cost price in your recipes per application.
What about weight loss from cooking or frying?
That's a separate loss on top of cleaning loss. Vegetables lose 10-30% weight from moisture loss during cooking, but this doesn't affect your cost price.
Is it cheaper to buy pre-prepared product?
Calculate it case by case. Pre-prepared costs 40-60% more but has 0% loss. With vegetables showing high loss rates (over 30%), pre-prepared often wins.
How do seasonal changes affect vegetable weight loss?
Winter vegetables typically show 3-8% higher loss rates due to longer storage times and dehydration. Adjust your calculations quarterly for accuracy.
Should I factor in staff skill level for loss calculations?
Absolutely. Experienced prep cooks can reduce loss by 2-5% compared to beginners through better knife work and technique.
⚠️ EU Regulation 1169/2011 — Allergen Information — https://eur-lex.europa.eu/eli/reg/2011/1169/oj
The allergen information on this page is based on EU Regulation 1169/2011. Recipes and ingredients may vary by supplier. Always verify current allergen information with your supplier and communicate this correctly to your guests. KitchenNmbrs is not liable for allergic reactions.
In the UK, the FSA enforces allergen regulations under the Food Information Regulations 2014.
📚 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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