Does anyone know how to replicate this kind of steaming beverage effect? I've tried a tutorial that involves putting shapes with various wiggle expressions into a comp and then blurring out that comp and using Alpha Curves to get the kind of metamorphosis effect, but it doesn't look naturally 'twisty' like steam does.
The example you provided looks far more like a matte and moving shapes than any effect.
It looks like there are rounded rectangles on both sides that move up and a couple circles with an increasing radius that expand. Then that composition is used as a matte for the white.
Does that help? or are you looking for a different style than the one attached?
Agree. That is rather clearly meticulous shape animation. If you want "realistic" steam, lokk into Andrew Kramer's "Light Streaks" tutorials. The techniques are similar. Otherwise there's a million other ways just as well. You just have to experiment e.g. with distortion effects.