A falling film evaporator (1) for reducing a liquid content of a dairy product (DP), the evaporator (1) comprising a housing (2) having an inlet (3) and an outlet (4) for passing a heating media (H) through the housing (2), a number of heat transfer tubes (10) that are vertically arranged inside the housing (1) such that the heating media (H) can flow over outer surfaces (15) of the heat transfer tubes (10), each heat transfer tube (14) of the heat transfer tubes (10) comprising an upper inlet (17) and a lower outlet (18) for passing the dairy product over an inner surface (16) of the heat transfer tube (14). Each heat transfer tube (14) comprises corrugations (20) that extend along the length of the heat transfer tube (14).
