Which milk alternative is best in coffee?

Ranked for coffee, with the caveat that taste is personal.

Oat, barista edition

The best all-rounder. Foams close to dairy, tastes mildly sweet and cereal-like without dominating, and does not curdle in hot acidic coffee.

Standard supermarket oat milk is considerably worse at all three. The barista version adds fat, usually rapeseed oil, plus stabilisers — that is the whole difference.

Soy, barista edition

Foams well and holds structure. A stronger flavour of its own that some people like and some find intrusive. More prone to curdling than oat in very hot or very acidic coffee.

Almond

Low in both protein and fat, so it foams poorly and thinly. Barista versions improve it. The flavour is delicate and easily lost.

Coconut

Fatty and it foams into large unstable bubbles. Strong flavour that dominates. Fine in an iced drink, difficult in a cappuccino.

Technique adjustments

Stop cooler — 55 to 60 °C rather than 60 to 65. Plant proteins denature earlier and overheated oat milk goes thin and splits.

Stretch less, spin more. Plant milks take air readily and hold it poorly.

Pour immediately. Plant foam separates faster than dairy.

Curdling

Caused by acidity and heat, not by foaming. Barista formulations are stabilised against it; standard ones split in a hot light-roast espresso.