When will the cream form faster in a saucepan of milk – in the refrigerator or in the room?

Cream forms faster in the refrigerator because at low temperatures the Brownian motion of fat droplets in milk is weaker. Consequently, the upward movement of these droplets becomes easier because of the less drag. These droplets have a lower density compared to the rest of the milk content, and they float to the very top under the action of a buoyant force.
Explanation:
Brownian motion is the random motion of microscopic particles of a solid, which is caused by the thermal motion of liquid particles.