What is a Post Mix System

Post mix ice and beverage dispensers have evolved from small, manually loaded countertop units with as few as four valves to today’s larger capacity multi-valve units to support the increased importance of post mix system beverages in today's restaurants, cafeterias and convenience store operations. A post mix system is a bit more involved. A post mix system is defined by delivering a heavy concentrated beverage base and a diluent for the concentrated syrup to a dispense nozzle, adding one or more of colors, flavors and any additives to the beverage base and diluent to provide a completed carbonated beverage, and delivering this drink into a cup for service to a customer. This type of machine will always house the diluent separately from the concentrated syrup. The concentrate pump works in conjunction with a diluent pump to deliver the concentrate and diluent into a valve for mixing and dispensing of the final product with a higher level of consistency every time.

Soda dispensers can be made available in several different configurations.  The first are the self-serve variety.  These are generally positioned in easy reach of a customer so they can dispense as much product as they require.  Some dispensers are coupled with built-in ice makers.  Other post mix systems have bins that require ice to be transferred to the machine from an outside source.  The second varieties are soda guns. These are operated exclusively by bartenders or servers in the restaurant. These are generally equipped with a push button design that allows the operator to quickly and easily switch between flavors.

A post mix system for dispensing a finished beverage directly from a pliable beverage concentrate having an ice point at or near freezer temperatures, with little or no conditioning. The system preferably uses a one-piece, unitary, disposable package that includes both the concentrate container and a positive displacement metering pump. The disposable package is placed in the dispenser which automatically connects the pump to a pump motor. A mixing nozzle is connected to the metering pump and a water line is connected to the mixing nozzle. Upon pushing a load button, the dispenser automatically feeds compressed air on top of a piston in the concentrate container to force concentrate into the pump. The dispenser automatically reads an indicator on the package to set the pump speed in response to the type of concentrate in the package. The dispenser requires no clean-up or sanitization and allows rapid flavor change.

When it is desired to replace the concentrate container either with a full one or with a different product, the one-piece, integral package including the concentrate container and the metering pump is removed and replaced with a different package. The mixing nozzle which has been attached to the pump can also be removed with the one-piece package. Thus, because all product contact surfaces are disposable, the dispenser requires virtually no cleanup or sanitization, and a rapid flavor change can be made.

A post mix system also uses C02 to supply the carbonated chilled or water but the mixing doesn't occur until the syrup reaches the deliver nozzles the ratio of syrup to water is controlled at the nozzle.