Methods and apparatus for producing saline slush for surgical applications. Producing surgical saline slush in a slush bottle that is a rigid or semi-rigid, high integrity, sturdy container that resists punctures and leaks to better maintain a sterile barrier and does not rely on having an external object placed in the fluid to mix the slush. Slush is agitated by rotating the slush bottle within a slush bottle carriage around an axis of rotation. Agitation of the slush may be increased by including an agitation feature such as at least one fin in one or more sidewalls of the slush bottle. The rotating slush bottle is chilled. One variation is to keep the sterile saline in a flexible container and tumble the flexible container in a rotating slush bottle. Other variations are suggested.