Mash Calculator Worksheet
by Len Spencer
(from the formula in the Sept. 1997 Brew Your Own magazine)
Note on numbers: With this worksheet, just keep in mind that all
weights must be in the same of unit of measure (pounds, kilograms,
etc.). Also, all temperatures must be in the same scale (Celsius
or Fahrenheit). Also, I have a place for boiling point of water
because higher altitudes will have a lower boiling point. Also,
1 gallon of water weighs 8.32 pounds.
Section 1: Working Variables
A. Ambient temperature of grain: __________
B. Weight of grain: __________
C. Weight of water: __________
D. Desired mash temperature: __________
Section 2: First rest temperature
E. Subtract A from D: __________
F. Multiply B times 0.382: __________
G. Multiply F times E: __________
H. Divide G by C: __________
I. Add H to D: __________
Result I is the strike temperature of the mash water, assuming
a preheated mash tun.
Section 3: Second rest temperature (based on maintaining
first rest temperature)
J. Local boiling point of water __________
K. Desired second rest temperature __________
L. Subtract D from K: __________
M. Add C to F: __________
N. Multiply M times L: __________
O. Subtract K from J: __________
P. Divide N by O: __________
Result P is the weight of boiling water to add to the mash
to reach the second rest temperature.
Section 4: Third rest temperature (NOT recommended due to the
potential high volume, but included here anyway for reference)
Q. Desired third rest temperature __________
R. Add P to M: __________
S. Subract K from Q: __________
T. Multiply R times S: __________
U. Subtract Q from J: __________
V. Divide T by U: __________
Result V is the weight of boiling water to add for the next rest.
Again, this is not recommended, due to the potential volume and
extreme thinness of the mash at this point.