Vertical batch freezer (1) for preparing a pasty food product, comprising at least one tub (2) open on top and having a side wall (2a) and a lower base (2b), at least one refrigeration cylinder (3) provided with a cavity (3 a) inside which said tub (2) is at least partially housed, said refrigeration cylinder (3) further comprising cooling means (4) to cool said pasty food product contained in said tub, said cooling means comprising at least one tubular duct (5) for passing a coolant, which extends along a curvilinear longitudinal axis (Z) arranged around and/or underneath at least part of said cavity, said duct (5) comprising at least one outer perimetrical surface (7) having a heat exchange zone (7a) facing said side wall (2a) and/or said lower base of said tub to directly exchange heat with the food product contained in said tub, characterized in that said heat exchange zone (7a) has, for at least one portion (5a) of said duct (5), along said curvilinear longitudinal axis (Z), cross section (9) having a substantially straight length (10a) facing said side wall (2a) and/or said lower base (2a) of said tub (2), said heat exchange zone (7a) being defined by the translation of said substantially straight length along said curvilinear longitudinal axis (Z) of said duct.Linvention concerne un congélateur discontinu vertical (1) pour la préparation dun produit alimentaire pâteux, comprenant au moins une cuve (2) ouverte sur le dessus et ayant une paroi latérale (2a) et une base inférieure (2b), au moins un cylindre de réfrigération (3) pourvu dune cavité (3 a) à lintérieur de laquelle ladite cuve (2) est au moins partiellement logée, ledit cylindre de réfrigération (3) comprenant en outre des moyens de refroidissement (4) pour refroidir ledit produit alimentaire pâteux contenu dans ladite cuve, lesdits moyens de refroidissement comprenant au moins un conduit tubulaire (5) pour faire passer un fluide de refroidissement, qui sétend le long dun axe longitudinal curviligne
