Milk contributes two things to a coffee drink, and they come from different components.
Protein makes the foam
Casein and whey proteins surround air bubbles and stabilise them. Protein content is what determines whether milk foams at all.
Skimmed and whole milk have similar protein — around 3.4 g per 100 ml — so both foam.
Fat makes the texture
Fat gives body, mouthfeel and sweetness, and it slows bubble collapse by coating them.
What each gives you
Whole (3.5%) — the best balance. Rich texture, sweet, stable microfoam, and it holds a pour. The default in every café.
Semi-skimmed (1.5–2%) — foams readily and slightly more voluminously, with less body. Perfectly usable.
Skimmed (0.1%) — foams the most volume and produces dry, stiff foam that collapses fast. Thin in the mouth, and it makes latte art harder rather than easier.
The idea that skimmed milk is better for foam is a persistent myth — it makes more foam, not better foam.
Freshness matters more than percentage
Older milk foams worse. Protein degrades over the milk’s life, and milk near its date will not hold a texture.
Use fresh milk and keep it cold — under 4 °C — right up to the moment you steam it.
The verdict
Whole milk, fresh, cold.
Last reviewed 8 August 2026