In Vessel Volume Graph
As steps are added, the mash schedule graph becomes active. The horizontal axis of the graph illustrates duration, or elapsed time. The vertical axis shows temperature, volume or both.
It is important to realize that the "In Vessel Volume" column represents only one vessel at a time, but the referenced vessel varies depending upon which line of the schedule it appears on; specifically, during the mash and prior to a step which 'transfers' or 'separates', the "In Vessel Volume" refers to the total volume occupied by the mash in the mashtun -- including both the volume of water added and the volume of the grain. When a portion is transferred or separated, then on that line the "In Vessel Volume" refers to the volume of that vessel, e.g., the kettle.