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Barista

Oat milk will not foam: here is why

Not every plant milk is made for foaming. What the label says and what actually counts.

10 min read

Cow milk foams because protein and fat together form a stable shell around the air bubbles. Plant drinks have to rebuild that -- and they do it with varying success.

The barista version is not just marketing

Barista variants contain more fat and an acidity regulator, usually dipotassium phosphate. The fat carries the foam, the regulator prevents curdling in hot, acidic espresso. Ordinary oat milk has neither and readily curdles on contact with coffee.

What else helps

  • Start cold -- straight from the fridge, not pre-warmed.
  • Draw in less air than with cow milk, but roll it for longer.
  • Heat to 60 degrees at most; above that the foam collapses.
  • Let the espresso rest briefly before the milk goes in.

Soy drink, by the way, foams most stably but curdles fastest. Oat is the compromise that works with most coffees.

We serve oat, soy and almond at no extra charge. If something does not taste the way you expected, say so -- we will make it again.