A food processing vat is provided with a zoned heat transfer system that includes a heat exchanger with a baffle that extends between a pair of spaced apart sheets. The baffle directs a flow of a heat transfer fluid through a void space between the sheets of the heat exchanger. The heat exchanger may also include multiple spaced apart posts that extend through the heat exchanger and around which the heat transfer fluid can flow. The posts and/or baffle may be defined by welded points of joinder between the sheets, and the sheets may be inflated to provide the space therebetween, such that the posts and/or baffles extend as webs of material that connect the sheets of the heat exchanger.
