Boil up refers to the literal act of heating a liquid; often used in culinary contexts.

Physical Action

'Boil up' often indicates the beginning of the cooking process.

Starting Point

Used metaphorically, 'boil up' describes a sudden increase in strong feelings.

The phrase implies a rapid transition from calm to anger.

Despite its intensity, 'boil up' can imply an internal struggle to remain composed.

'Boil up' describes a situation reaching a critical or dramatic stage.

The phrase suggests a gradual build-up to a significant moment.