Beverage dispensing device, beverage dispensing method, and beverage dispensing system

A beverage dispensing device that uses a combination of tubes each having a flexible portion that is elastically deformable as a passage of a beverage, the beverage dispensing device comprising a mechanism configured to set a bore of the flexible portion to a first state having a first cross-sectional area or a second state having a second cross-sectional area that is smaller than the first cross-sectional area, selectively, wherein:

• when the bore of the flexible portion is in the second state, foam is generated from the beverage flowing through the tube,
• the mechanism comprises a pressing mechanism configured to press the flexible portion,
• the pressing mechanism comprises a pressing portion, the pressing portion comprising a pair of members facing each other with the flexible portion interposed therebetween,
• one of the pair of members of the pressing portion is a holder member configured to contact with the flexible portion and hold the flexible portion when the bore of the flexible portion is in the first state and the second state,
• the other of the pair of members is a pressing member configured to press the flexible portion when the bore of the flexible portion is switched from the first state to the second state,
• the other of the pair of members comprises
• a pair of protruding portions protruding toward the one of the pair of members and facing each other with a central axis of the flexible portion that is disposed between the pair of members interposed therebetween;
• and
• a groove provided between the pair of protruding portions, and
• the groove has a depth such that the flexible portion in the second state is out of contact with a bottom surface of the groove.