Ask a café owner which drink sells most and you'll almost always get the same answer: flat whites, lattes, cappuccinos. Ask them which drink makes the most profit, and very few will know the answer without looking it up.
The drinks your customers buy most often are frequently the ones you're making the least money on. Here's why — and what to do about it.
The Per-Serve Cost of a Milk-Based Drink
Let's work through the real numbers for a standard flat white:
| Component | Volume | Cost | |-----------|--------|------| | Espresso (house blend at £14/kg, 18g dose) | 18g | £0.25 | | Whole milk (at £1.20/2L) | 150ml | £0.09 | | Cup + lid + sleeve | — | £0.08–£0.12 | | Total COGS | | £0.42–£0.46 |
At a typical selling price of £3.80, that's a gross margin of around 88%. Excellent, right?
Here's the problem: most cafés aren't making flat whites with whole milk anymore. The majority of their volume is oat milk, almond milk, soy milk — and those change the numbers completely.
The Alt Milk Problem
A 1-litre carton of oat milk at trade pricing is typically £0.85–£1.10. Compare that to whole milk at roughly £0.60/litre. For a standard flat white, the milk component moves from £0.09 to approximately £0.13–£0.18. That doesn't sound significant, but:
- Alt milk drinks now represent 40–60% of volume in many independent cafés
- The cost difference compounds across every single one of those orders
- Most cafés are not charging enough of a surcharge to cover it
A 30p alt milk surcharge sounds like a lot until you run the maths. The actual cost uplift is 4–9p per drink. A 30p surcharge adds 21–26p of margin per drink. On 60 alt milk drinks per day, that's £12–£15 of additional daily margin — over £4,000 per year, before tax.
The cafés that don't charge an alt milk surcharge, or charge an inadequate one, are simply giving away margin at scale.
Cup Size Strategy
The other dimension that's almost always underpriced is size. Many cafés add just 20–30p for a large drink, but the actual cost increase is:
- Additional 50–80ml of milk: £0.03–£0.06 (whole milk) or £0.04–£0.09 (oat milk)
- Larger cup and lid: +£0.03–£0.05
- Total additional COGS for a large: £0.06–£0.14
A 20p upcharge on a large drink is often leaving money on the table. Most customers are remarkably price-insensitive to the difference between a 20p and a 50p size premium when they're already spending £3.80. Rounding up your size premium to 40–50p is rarely the reason a customer walks out.
Doing the Real Maths
The mistake most new café owners make is calculating their food cost percentage on their full menu and feeling fine about it. But averages hide a lot. A 28% food cost across your menu might include:
- A takeaway espresso with a food cost of 9%
- A large oat milk latte at food cost of 21% (well-priced)
- A large oat milk latte at food cost of 29% (underpriced)
When you separate your drinks into sub-categories and run the cost percentage on each one, the leaks become visible.
Good benchmarks for milk-based espresso drinks:
- Target food cost: 18–22%
- Alt milk upcharge: at minimum covers the cost difference, ideally adds margin
- Size premium: 40–60p for large, depending on cup size delta
What to Do Next
The most useful exercise is to cost your five best-selling drinks individually. Not an average — each one. Identify which ones are performing and which are quietly bleeding margin.
Then review your alt milk surcharge and your size pricing independently. These are the two highest-leverage adjustments in most café menus, and neither requires a full menu reprint or a significant customer communication.
For a comprehensive review of your menu's financial architecture — from cost of goods through to price positioning — menu engineering support can help you build a menu that works as hard as you do.
The One Number to Know
If you're starting from scratch, here's the single most useful number: your target food cost percentage for drinks should sit between 18–24%. If any category is regularly above 25%, it's worth a closer look. If it's above 30%, you're paying to make that drink.
Know your numbers. Price accordingly. The margins are there — they just need to be claimed.