Water Volumes for Brewing All Grain

  • It is important to use the right amount of water because…
    • Too much water = too much wort at a lower gravity
    • Not enough water = too little wort at a higher gravity

  • Calculate backwards from your batch size
  • Batch size: 5 gallons
  • Kettle Loss: Post Boil / Post Cool Down losses at the bottom of your kettle; proteins, hops, misc. sludge
    • Can be as much as 3 quarts depending on hopping rates
    • Brewstock’s system is ~2 quarts of loss, +- depending
  • Boil Rate: How much is boiled off:  ___ gal/hour … GPH if you will. 
    • Typically 3-4 quarts per hour
    • Depends on your system! Propane burner? Electric Kettle? Stove top? 
  • Boil Size = Batch size + Boil Rate + Trub Loss
    • Example: 5 gallons + 3 quarts + 2 quarts = 6.25 gallons boil size
  • Grain Absorption: How much liquid is lost in the grains
    • Typically ~0.5 quarts per pound of grain
    • 12 lbs of grain x 0.5 quarts = 6 quarts of loss (1.5 gallons) in the mash tun
  • Total Water: How much water do I need to brew 5 gallons of beer
    • Batch Size + Kettle Loss + Boil Rate + Grain Absorption = Total Water
    • 5 gal batch Size + 0.50 gal kettle loss + 0.75 gal boil off + 1.5 gal grain absorption = 7.75 gallons

How do I know what the variables are on my system?

  • Trial and Error!
  • These numbers can change based on a number of factors not limited to…
    • kettle size
    • heat source
    • hopping rates
    • types of grains used
    • environment
    • humidity
  • A quick and easy way to figure our your average boil rate for your system…
    • Fill your kettle with a specified amount of water and boil for 60 minutes… Try 6 gallons to mimic a brew day
    • After the boil, let it naturally cool and measure the amount left over. The delta is your boil rate per hour.

Quick note for Brew in a Bag brewers… This process is nearly identical with the exception of grain absorption. 

  • If you squeeze the bag (encouraged), there will be significantly less grain absorption loss
    • Try targeting somewhere around 0.2 – 0.3 quarts per pound lost in the grains
    • Subsequently, you might need ~0.75 gallons less starting water.