Vertical batch freezer (1) for preparing a pasty food product, comprising a frame (2) having an upper bearing plane, a tub (3) open on top for containing the food product to be batch frozen, at least one refrigeration cylinder (4) provided with a cavity (4a) inside which said at least one tub is at least partially and removably housable, at least one grip element (5) to remove/introduce said tub (2) from/into said cavity (5a), and fastening means (6) to reversibly prevent the rotation and/or translation of said tub (3) with respect to said frame (2) of said batch freezer (1), at least when said tub (3) is housed inside said cavity (5a) of said refrigeration cylinder (5), characterized in that said reversible fastening means (6) comprise at least one retaining element (7) and at least one hooking element (8) for said retaining element integrally constrained to said upper plane of said frame, said at least one retaining element (7) being movably constrained with respect to said tub (3) between a position (PI) of disengagement from said at least one hooking element (8), wherein said tub (3) is removable from said cavity (5a), and a position (P2) of engagement with said at least one hooking element (8), wherein said tub is locked to said frame.
