Formulas
Temperature conversions
Fahrenheit to Celsius
C = (F – 32.0) / 1.8
Celsius to Fahrenheit
F = (C * 1.8) + 32.0
Attenuation:
Attenuation = 100 % * (starting gravity – current gravity) / (starting gravity – 1)
Hop Calculations:
AAU
AAU = Weight (oz) x % Alpha Acids (whole number)
IBU
IBU = AAU x Utilization(gravity of the boil and the boil time) x 75 / Volume of Recipe
Tinseth equation
Utilization = f(G) x f(T)
where:
f(G) = 1.65 x 0.000125^(Gb – 1)
f(T) = [1 - e^(-0.04 x T)] / 4.15
SRM
Morey’s Formula
SRM = 1.4922 [(MCU) ^ 0.6859]
Daniels’ Formula
SRM = (MCU * 0.2) + 8.4
Mosher’s Formula
SRM = (MCU * 0.3) + 4.7
*MCU = Malt Color Units
Specific Gravity v. Plato
Degrees Plato to Gravity Conversion
{Plato/(258.6-([Plato/258.2]*227.1)}+1 = Specific gravity
Gravity to Degrees Plato Conversion
degrees P = SG points/4
degrees P = 259/SG and SG=259/259-degrees P (more accurate)
Mash and Sparge Calculations
Absorbtion
Water absorbed by Grain (A) = 0.2 gallons of water / 1 pound of grain
(To measure your system) (A) = Sparge Water Added – First Runnings Collected – Loss To Tun
Evaporation
Evaporation % (E) = 100 – (post-Boil volume * 100 / pre-Boil volume)
Mash Tun Loss
Mash Tun Loss (M) = 0.5 gallons (amount liquid left in Mash Tun after sparge, varies per system)
Cooling Loss
Cooling Loss (C) = 4% of pre-cooling volume
Trub Loss
Trub Loss (T) = 1 gallon (very specific to each system)
System Loss
System Loss (S) = ((Final Volume + T) / C) / E)
Total Water Needed
Total Water Needed (W) = S + M + A
Mash Thickness Ratio
Mash Thickness Ratio (R) = 1.5:1 (thick), 2.5:1 (medium), 3.5:1 (light)
(R) = quarts of water to pounds of malt
Total Mash Water
Total Mash Water (in gallons) = (R * (Total lbs Grain)) / 4
Total Sparge Water
Total Sparge Water = Total Water Needed (W) – Total Mash Water
Strike Water Temperature
*Does not account for heat loss from mash tun.
Aa + Bb = Cc
A = Total Weight of Grain (lbs) * Specific Heat of Grain
B = Total Volume of Water (gal) * Specific Heat of Water
C = A + B
a = Temperature of Grain
c = Mash Temperature Target
b = ?
b = (Cc – Aa)/B
Pre-Boil Gravity
pre-boil gravity = (post-boil gravity (everything right of the decimal)) * (post-boil volume) / (pre-boil volume)
Hydrometer Temperature Adjust
Correced Gravity = A1*((1.00130346-0.000134722124*A2+0.00000204052596*A2^2-0.00000000232820948*A2^3)/(1.00130346-0.000134722124*A3+0.00000204052596*A3^2-0.00000000232820948*A3^3))
A1 = Specific Gravity
A2 = Measured Temperature
A3 = Hydrometer Calibrated Temperature