GlossaryΒΆ

Alpha Acid Units (AAU)
Defined as \(\text{AAU} = \text{weight of hops} \times \text{alpha acids}\).
Apparent Extract (AE)
The measured hydrometer reading for the finished beer.
BJCP
Beer Judge Certification Program. Publishes style guidelines for beer.
Boil Gravity
The specific gravity of the wort before it has been boiled and cooled. For a recipe where the boil volume is greater than the fermenting volume this can mean a gravity that is much lower than the Original Gravity. If the boil volume is less than the fermenting volume (ie water is ‘topped up’) then the gravity can be much higher than the OG.
Boil Volume
The volume of the wort during the boil.
Brew House Yield (BHY)

Brew house yield is a measurement that tells the efficiency of the brewing. The actual degrees Plato from the brew and the actual gallons collected out of the kettle are needed to calculate the BHY.

\(\text{BHY} = \frac{P_{actual} \times \text{vol}_{actual} \times \text{BHY}_{target}}{P_{target} \times \text{vol}_{target}}\)

Cereal
A type of whole grain used for brewing.
DME
Dry Malt Extract
Final Gravity
The specific gravity of the beer after it has been fermented. The final gravity measures the density of a sugar, alcohol, and water mixture which is different than the original gravity which only measures sugar and water. This is why refractometers must be adjusted when used to measure FG.
Final Volume
The volume of the wort at the finish of the boil.
Gravity Units (GU)

The gravity units of a recipe is defined as the total points of the recipe (as measured in PPG or HWE depending on units) divided by the volume of the wort.

\(\text{GU} = \text{PPG} \div \text{Wort Volume}\)

Hot Water Extract

The international unit for the total soluble extract of a malt, based on specific gravity. HWE is measured as liter*degrees per kilogram, and is equivalent to points/pound/gallon (PPG) when you apply metric conversion factors for volume and weight. The combined conversion factor is:

\(\text{HWE} = 8.3454 \times \text{PPG}\)

International Bitterness Units (IBUs)

IBUs or International Bittering Units measures a bitterness unit for hops. IBUs are the measurement in parts per million (ppm) of iso-alpha acids in the beer. For example, an IPA with 75 IBUs has 75 milligrams of isomerized alpha acids per liter. The equation used to calculate the weight of hops for the boil is as follows.

\(\text{Ounces hops} = \frac{\text{IBU Target} \times \text{galbeer} \times \text{IBU%}}{\text{%a-acid} \times \text{%Utilization} \times 7489}\)

The IBU target equals the total bitterness for the beer. (e.g. an IPA may have an IBU target of 75 IBUs) The percent IBU is equal to the percent of IBUs from each hop addition. You may wish for your first hop addition to contribute 95% of the total IBUs. This would make your IBU% 95%. The %a-acid is the amount of alpha acid in the hops and can be found on the hop packaging. The % Utilization is a measurement of the percentage of alpha acid units that will isomerize in the boil. The following chart outlines the typical utilizations and hop boil times.

Boil Time Utilization
60 min 30%
30 min 15%
5 min 2.5%

The 7489 is a conversion factor and used to cancel the units in the equation, converting oz/gallon to mg/l. For the hops equation, the units for the % must be expressed in decimal form. (e.g. 10%= .10)

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LME
Liquid Malt Extract
Malt Color Units (MCU)

The color of malt as a function of weight, beer color, and wort volume.

\(\text{MCU} = \frac{\text{grain weight} \times \text{beer color in SRM}}{\text{wort volume}}\)

Mash Water Volume

To calculate the mash water volume you will need to know your liquor to grist ratio. The term liquor refers to the mash water and grist refers to the milled malt. We need to calculate the appropriate amount of water to allow for enzyme action and starch conversion take place.

\(\text{gallons H2O} = \frac{\text{Lbs malt} \times \text{L:G} \times \text{1 gallon H2O}}{\text{8.32 pounds water}}\)

Original Gravity
The specific gravity of the wort after it has been cooled and put into the fermenter.
Original Volume
Start Volume
The volume of the wort at the beginning of the process.
Plato
Degrees Plato
Degrees Plato is the weight of the extract in a 100gram solution at 64 degrees Fahrenheit.
Real Extract
The real extract content of the finished beer.
Specific Gravity
The ratio of the density of the wort against the density of water.
Standard Reference Method (SRM)
SRM is the standard unit of measure of the color of beer
Strike Water

As you know when you are mashing, your strike water has to be warmer than the target mash temperature because the cool malt will cool the temperature of the water. To correctly calculate the temperature of the strike water, use the following formula.

\(\text{Strike Temp} = \frac{0.4 \times \big(\text{T}_{mash} - \text{T}_{malt}\big)}{L:G} + \text{T}_{mash}\)

Weight of Extract

The weight of extract is the amount of malt extract present in the wort.

\(\text{Lbs extract} = \text{density of water} \times \text{gal of wort} \times \text{SG} \times \frac{P}{100}\)

The weight of one gallon of water in the above formula is 8.32 lbs/gal

To find the weight of a gallon of wort, multiply the specific gravity of the wort by the density of water.

Plato is a percentage of sugars by weight. So 10 Plato means solution is 10% sugars. In this equation we convert the degrees plato to a decimal number between 0.0 and 1.0 by dividing it by 100. This is multiplied by the weight of a gallon of wort.

Working Yield

The product of the Hot Water Extract multiplied by the Brew House Yield. This product will provide the percent of extract collected from the malt.

\(WY = \text{HWE as-is} \times \text{BHY}\)

Wort Color

The color of the wort

\(\text{Color of Wort} = \text{S} \times \text{% extract} \times \text{L of malt} \times \frac{\text{P wort}}{\text{8P reference}}\)

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