Portion Control and Waste in a Cafe (UK)
How portion drift and end-of-day waste quietly rewrite a costed menu.
The short answer
Portion drift and waste are the two things that move a costed menu without anyone changing a price. A dish costed at 120g of filling but served at 150g is running a food cost a quarter higher than the menu assumes, and food thrown away at close is food you bought and did not sell, so it belongs in the cost of what you did.
Step by step
- Cost the portion you actually serve. Weigh what goes on the plate during service, not what the recipe card says. The gap is usually generous.
- Build waste into the cost, not the apologies. If eight percent goes in the bin, the dishes you sell have to carry it. Pretending otherwise flatters every number you have.
- Track waste by item for a fortnight. It is nearly always concentrated in two or three lines rather than spread evenly.
- Fix the cause before the price. Over-prepping, a slow seller, or a portion nobody finishes. Raising the price of a dish you throw away does not help.
What 30g of portion drift costs
A dish costed at 120g of filling at £9.80 a kilo, sold at £4.50.
| Line | Amount |
|---|---|
| Costed portion, 120g | £1.18 |
| Food cost at £4.50 | 26.1% |
| Served portion, 150g | £1.47 |
| Food cost at £4.50 | 32.7% |
| Extra cost per plate | £0.29 |
| Across 40 plates a day | £11.76 |
Six and a half points of GP and nearly £12 a day, from a spoon that is slightly too generous. Over a year, on one dish, that is roughly £4,200.
Why it matters
Portion drift and waste are invisible on a price list and obvious in a bank balance. Costing the portion you truly serve, and carrying waste as a real cost, is what keeps a menu honest between price reviews.