A vat system for processing liquid or semi-liquid compositions, comprises a vat 10 that includes a bottom wall and side walls extending upwardly from the bottom wall, and a zoned heat transfer system 50. The zoned heat transfer system 50 includes a first void space 105 through which a heat transfer fluid 100 can flow for transmitting heat to or removing heat from a first portion of at least one of the bottom and side walls of the vat 10 and a second void space 105 through which the heat transfer fluid 100 can flow for transmitting heat to or removing heat from a second portion of at least one of the bottom and side walls of the vat 10. The zoned heat transfer system 50 selectively directs the heat transfer fluid 100 through the first and second void spaces for selectively transmitting heat to or removing heat from different portions of at least one of the bottom and side walls of the vat 10.
