Determine the amount of mash and sparge water to use while brewing
Calculate the amount of mash and sparge washer you need to start your batch with.
The volume of beer you aim to ferment.
The total amount of grains used in the mash and boil. These are grains that can absorb water and reduce the final volume.
The length of time you boil your wort. The longer you boil, the more water you'll need to start with.
The ratio of water to grains in your mash. Typically 0.375 to 0.5 gal/lb or ~ 3 to 4 liter/kg.
Provide details about the wort loss due to equipment.
The amount of wort left behind in your mash tun after laudering.
The amount of wort left behind when transferring from the boil kettle to the fermenting vessel.
Standard constants used in the calculation. Typically you do not need to adjust these, but you are welcome to if you like.
The percentage of wort you loss per hour of boil. This is typically 10% per hour.
The percentage which the volume of boiling wort shrinks when cooling to 68 degrees. This is a well-accepted constant value of 4%.
This is the number of gallons of water absorbed per pound of grain during the mash in your system. You will need to measure and adjust this value for your system parameters as they can vary greatly. Ray Daniels in Designing Great Beers recommends a value of 0.20 gal/lb and Denny Conn observes a value of 0.10 gal/lb in his system.
