- Malt Weight - This field indicates the amount of malt used. Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated.
- Weight Units - This field is used to indiciate the weight units used by the calculator. Click on the button in the corner of the field to change the units and convert the Malt Weight and Decoction Weight fields to the new units.
- Malt Heat Capacity - This field is used to indiciate the heat capacity of the crushed malt. Typically this number is about .4 and varies depending on the moisture content of the malt. The following table shows the malt heat capacity (MHC) as a function of its moisture content.
% moisture MHC in Btu/lb/degF 0 0.38 2 0.39 4 0.40 6 0.41

Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated. - Water Volume - This field is used to indiciate the amount of water that has already been added to the mash. Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated.
- Volume Units - This field is used to indiciate the volume units used by the calculator. Click on the button in the corner of the field to change the units and convert the Water Volume and Infusion Volume to the new units.
- Current Temp - This field is used to indiciate what the current temperature of the mash is. Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated.
- Temperature Units - This field is used to indiciate the temperature units used by the calculator. Click on the button in the corner of the field to change the units and convert the Current Temp, Added Temp, and Final Temp to the new units.
- Final Temp - This field is used to indiciate what the current temperature of the mash is. Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated.
- Added Temp - This field is used to indiciate what the temperature of the additional water or decocted mash added needs to be. Changing this field will cause the Infusion Volume and Decoction Weight to be recalculated.
- Infusion Volume - This field is used to indicate the amount of water that will be added to hit the temperature specified by the Final Temp field. Changing this field will cause the Added Temp of the water to be recalculated.
- Decoction Weight - This field is used to indicate the mass of the mash that will be removed, heated and added back to the mash to hit the temperature specified by the Final Temp field. Changing this field will cause the Added Temp of the decoction to be recalculated.

- Recalc - Click this button to perform calculations.
- Ok - Click this button to exit the calculator.

- Calculating Initial Strike Water Requirements - The calculator can be used to determine the amount of initial strike water required to reach a mash temp. This is done by following these steps:
- Enter the Malt Weight. This is the total amount of grain being mashed.
- Enter the Malt Heat Capacity.
- Enter the Water Volume as 0 (since there has been no water added so far).
- Enter the Current Temp. This is the temperature of the grain currently.
- Enter the Final Temp. This is the temperature you want the mash to end up at.
- Enter the Added Temp. This is the temperature of the water that will be added. If you wish to use a certain mash thickness and have the calculator to tell you the temperature of the strike water to use, skip this field and enter a value in the Infusion Volume field.
- Enter the Infusion Volume. This is the volume of water that will be added to reach the indicated final temperature. Changing this value will cause the Added Temp field to be recalculated.

The calculator should now be indicating the Infusion Volume and the Added Temp required to hit the Final Temp.

- Calculating Step Infusion Water Requirements
- Enter the Malt Weight. This is the total amount of grain being mashed.
- Enter the Malt Heat Capacity.
- Enter the Water Volume. This is the total volume of water that has been added so far.
- Enter the Current Temp. This is the temperature of the mash currently.
- Enter the Final Temp. This is the temperature you want the mash to end up at.
- Enter the Added Temp. This is the temperature of the water that will be added. If you wish to add a certain volume of water and have the calculator to tell you the temperature the water should be, skip this field and enter a value in the Infusion Volume field.
- Enter the Infusion Volume. This is the volume of water that will be added to reach the indicated final temperature. Changing this value will cause the Added Temp field to be recalculated.

The calculator should now be indicating the Infusion Volume and the Added Temp required to hit the Final Temp.

- Calculating Decoction Mash Requirements
- Enter the Malt Weight. This is the total amount of grain being mashed.
- Enter the Malt Heat Capacity.
- Enter the Water Volume. This is the total volume of water that has been added so far.
- Enter the Current Temp. This is the temperature of the mash currently.
- Enter the Final Temp. This is the temperature you want the mash to end up at.
- Enter the Added Temp. This is the temperature of the decoction when it is added back to the main mash. Typically this is the boiling temp of water where you live. If you wish to decoct a certain mass of the mash and have the calculator to tell you the temperature the decoction should be when added back, skip this field and enter a value in the Decoction Weight field.
- Enter the Decoction Weight. This is the mass of the mash that will be decocted and added back to the mash to reach the indicated final temperature. Changing this value will cause the Added Temp field to be recalculated.

The calculator should now be indicating the Decoction Weight and the Added Temp required to hit the Final Temp.

Tf = (Hc1*M1*T1 + Hc2*M2*T2)/(Hc1*M1+Hc2*M2)

Where:

- Tf = final temperature
- Hc1 = heat capacity of first mass
- M1 = wieght of first mass
- T1 = current temperature of first mass
- Hc2 = heat capacity of second mass
- M2 = weight of second mass
- T2 = current temperature of second mass

Rearranging this formula, and using a value of 1 for the heat capacity of water, we come up with the following:

Ma = Hcm*Mm*(Tf-Tm)/(Tw-Tf)

Where:

- Ma = required mass of initial strike water
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt used
- Tm = current temperature of the malt
- Tf = final temperature desired
- Tw = temperature of initial strike water

Tw = (Ma*Tf-(Hcm*Mm)*(Tm-Tf))/Ma

Where:

- Tw = required temperature of initial strike water
- Ma = mass of initial strike water added
- Tf = final temperature desired
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt
- Tm = current temperature of the malt

Ma = (Hcm*Mm+Mw)*(Tf-Tmash)/(Tw-Tf)

Where:

- Ma = required mass of water to infuse
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt
- Mw = mass of water already in mash
- Tf = final temperature desired
- Tmash = current temperature of the mash
- Tw = temperature of infusion water added

Tw = (Ma*Tf-(Hcm*Mm+Mw)*(Tmash-Tf))/Ma

Where:

- Tw = required temperature of infusion water
- Ma = mass of water infused
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt
- Mw = mass of water already in mash
- Tf = final temperature desired
- Tmash = current temperature of the mash

Md = (Hcm*Mm+Mw)/(1+((Tf-Td)/(Tmash-Tf)))

Where:

- Md = required mass of decoction
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt
- Mw = mass of water already in mash
- Tf = final temperature desired
- Td = temperature of decoction when added back to mash
- Tmash = current temperature of the mash

Td = Tmash-(Hcm*Mm+Mw)/Md*(Tmash-Tf)

Where:

- Td = required temperature of decoction when added back to mash
- Tmash = current temperature of the mash
- Hcm = heat capacity of malt (about .4)
- Mm = mass of malt
- Mw = mass of water already in mash
- Md = mass of decoction
- Tf = final temperature desired

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Last Updated: 25-JAN-99