Device for foaming milk, beverage maker comprising said device, and method for foaming milk

A device for frothing up a liquid, in particular cold and/or unheated milk, which is configured for active introduction of air via an air supply line into the liquid, said device comprising:

• a liquid supply line for supplying the liquid,
• the air supply line which opens into the liquid supply line for supplying the air into the liquid,
• a discharge line which is configured downstream of the opening of the air supply line into the liquid supply line for discharging the mixture of liquid and air,
• a first conveying unit, in particular a pump, which is provided for conveying the liquid through the liquid supply line and/or the mixture through the discharge line and
• a mixing unit which is provided downstream of the opening in the discharge line, the mixing unit including at least one narrow place or being configured as narrow place(s) of the discharge line.