Appendix 4: Calculation of Initial Mash Temperature (Initial Heat) from the Liquor Temperature (Striking Heat)

If…
I = Initial mash temperature, °C or °F
S = Specific heat of the malt grist (from table below)
Tg = Temperature of malt grist. °C or °F
M = Mash thickness, hectolitres per 100 kg or barrels per quarter.
T = Temperature of liquor, °C or °F (Striking Heat)
Sc = Slaking heat correction, °C or °F (from table below)

Then

The equation may be used for °C or °F but the same temperature scale must be used throughout for
every individual calculation. Within the accuracy of the calculation, either means of expressing mash
thickness is permissible. The heat lost to and heat gained from the equipment has been ignored.

Typical Ranges of Values for Malt Specifications

% Moisture Specific Heat Slaking Heat Correction
0 0.38 3 ° 5.5 °F
1 0.38 2.8 °C 5 °F
2 0.39 2.3 °C 4 °F
3 0.40 2.3 °C 3.5 °F
4 0.40 1.5 °C 3 °F
6 0.41 1.3 °C 2.5 °F
8 0.42 1 °C 2 °F

Example:

A malt grist at 2% moisture and 27° C is mashed with liquor at 69° C at the rate of 2·68 hectolitres
per 100 kilograms.
What is the initial mash temperature?


Alternatively,
A malt grist at 2% moisture and 80° F is mashed with liquor at 156° F at the rate of 2·5 barrels per
quarter.

What is the initial mash temperature?


Reference
Pauls and Whites Brewing Room Book 1984/85.