An apparatus for cooling liquids that includes a tank that has two longitudinal walls, two lateral walls and a bottom, and cooling flasks that each of them has two longitudinal walls, two lateral walls and a bottom. The flasks are designed to contain coolant. The lateral walls and at least one longitudinal wall of each flask has at least one protrusion smaller than 2.5 millimeters. The flasks are designed to be set within the tank in such a way that the protrusions are attached to the longitudinal walls of the tank. The protrusions create a gap smaller than 2.5 millimeters between each two adjacent flasks and between the lateral walls of the flasks to the longitudinal walls of the tank. These gaps constitute a single cooling space. The total volume of the flasks is three times greater or more than the volume of the single cooling space.