Why Oat Milk Costs Extra, and When That Is Fair

Barista-grade oat costs a cafe roughly twice what dairy does per litre, sometimes more depending on the country and the brand. A bar selling a lot of milk drinks feels that difference immediately, and the honest response is either to raise all prices slightly or to charge for the substitution. Both are defensible.

What is harder to defend is a large surcharge on a drink that uses very little milk, or a surcharge in a place where most orders are already plant-based. At that point the extra is not covering a cost, it is a habit left over from when the carton was a rarity, and plenty of bars have quietly dropped it for exactly that reason.

What the pricing tells you

A cafe that has abolished the surcharge is usually a cafe where plant-based is the norm rather than an accommodation, and that tends to correlate with knowing how to steam it. A cafe with a large surcharge and one dusty carton is telling you where its attention is.

None of this is worth an argument at the till. It is worth knowing when you are choosing between two places on a street, and it is one of the few things you can check from outside, because the price list is usually in the window. If the substitution price is on the menu at all, someone has thought about it — the worst case is the place that charges you a surprise extra at the card machine.