The Frosty is one of the five original menu items that Wendy’s has had since its inception and was no small part of the reason that the franchise succeeded. But to achieve its famous texture, which falls neatly between rich, creamy soft serve and frothy milkshake, it must be served at precisely the right temperature.

Wendy’s initially outsourced production of the Frosty from a popular soft-serve shop in Columbus, Ohio. However, as the chain expanded, Wendy's switched gears by making the Frosty in-house in a specially designed Frosty machine.

These machines have a freezing chamber like a shake machine that uses rotary blades to continuously churn the Frosty mix and the refrigeration system of a soft-serve machine. The hybrid machines are designed to serve the drink "at a temperature of between 19 to 21 degrees" Fahrenheit in order to keep the mixture thick and retain optimal texture.