pH and temperature are the key parameters for controlling the enzymatic degradation of malt components.

If you don't mash in a kettle, the temperature step to a desired target temperature usually is reached by adding hot water (step-infusion) or a boiling partial mash (decoction). Thereby you may have to take into account that -besides the mash- the mashtun has to be heated, too. This heat capacity can be considered as system dependent constant. A good starting point for estimating this value is the mass of the mashtun -without insulation and cold parts (eg. outer casing).

You calculate the necessary temperature or partial mash as follows:

Take into account the drop in starting temperature of the mash, stored in the mashtun (it depends on the insulation and therefore it's a value of experience).

Note that the brewplanner can calibrate thermal mass, heat losses and heat input of your system. It thus can calculate temperature drops automatically for you.