Beer Calculations

 

Moisture Content

 

Moisture content is the percent of water in the dried malted barley.  The moisture content of malted barley will vary from 2 – 4%.  High moisture content in the malted barely subjects the malt to bacterial spoilage and flavor loss over time.

 

 

Color

 

Color of malt does not refer directly to the color of the grain.  Instead the color measurement expressed for example in degrees lovibond, references the color of the wort made from the malt at a specific gravity of 8 degrees Plato, which is a specific gravity of approximately 1.032.  Wort stronger than 8 degrees Plato will have a darker color. 

 

 

Hot Water Extract (HWE)

 

HWE is the amount extractable materials in the malt.  HWE is a measurement that shows everything extracted from the malt. (e.g. carbohydrates, soluble protein, and minerals)  HWE extract is usually reported on a malt analysis sheet in the dry basis.  A brewer will want to convert this number to the “as-is” basis to allow for the percent of water weight to be included in the recipe calculation. 

 

Specialty Malts

Specialty malts are used to give both flavor and color to the wort.  Three types of specialty malts are light malts, caramel malts, and roasted malts.

 

 

Light Malts

Light malts are made from slightly over-modified pale malts that are kilned at temperatures around 180 – 200 degrees Fahrenheit.  At this temperature, the enzyme capability of the malt is drastically reduced.  Examples of light malts are: Munich, imparts a pronounced grainy/malty flavor and a deep golden color; Vienna, imparts a small grainy flavor and a golden color; Smoked Malt, smoke flavor produced by burning various woods or peat during kilning. 

 

 

Caramel Malts

Stewing fully modified green malt during the kilning process produces caramel malts.  Color of caramel malt can range in color from 10 Lovibond to 120 Lovibond.  The darker the color the more flavor impact from the malt.  A general rule of thumb is that when the color is doubled, the flavor impact is quadrupled. 

 

 

Carapils (Dextrin Malt)

Carapils is also caramel malt but has a very light color, little caramel flavor, and provides non-fermentable extract.  Carapils is used to add mouthfeel and increase foam stability.  Usage varies from 1 – 10% in most styles. 

 

 

Roasted Malts

 

Malts made in a roasting drum are considered roasted malts.  There are three common types of roasted malts.  These are black malt, chocolate malt and roasted barley.

 

 

Black Malt

Black malt is used in many dark beers and is usually found in a porter recipe.  Black malt provides very astringent flavors but less than roasted barley.  This malt is also used to provide color in lighter beers like amber beer.

 

 

Chocolate Malt

Chocolate malt is roasted for a shorter amount time than black malt and at a lower temperature.  These conditions provide less color and fewer astringent flavors than black malt.  Chocolate malt is usually used to improve the characteristics of a porter.

 

 

Roasted Barley

Barley roasted with direct heat is roasted barley. Roasted barley is usually found in stout recipes. 


 

Specific Gravity (S.G.)

S.G. is the density of a liquid or solid compared to that of water.  The simple formula for S.G. is:

 

 

S.G. = 1 + 0.004 x °Plato

 

 

The more precise calculation of S.G. is:

 

 

S.G. = [(°Plato) / (258.6 – (°Plato/258.2 x 227.1))] +1

 

 

Plato

Degrees Plato is the weight of the extract in a 100gram solution at 64 degrees Fahrenheit.

 

 

°Plato = [(S.G. - 1) x 1000] / 4

 

 

The more precise calculation of Plato is:

 

 

°Plato = [(S.G.)2 – (205.347)] + (668.7183)(S.G.) – 463.371

 

 

Weight of Extract

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

 

 

Lbs extract =   [(8.32 lbs/gal wort)(gal wort)(S.G.)(°P)] / 100

 

 

8.32 in the above formula is the weight of one gallon of water.  To find the weight of a gallon of wort, multiply the specific gravity of the wort by 8.32lbs. 

 

 

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. 

 

 

BHY =  [(°Pactual)(galactual)(BHYtarget)] / [(°Ptarget)(galtarget)]

 

 

Working Yield

Working Yield is 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 =    (HWE as-is)(BHY)

 

 

Pounds of Malt

It is imperative that you measure your recipes by the percent of extract taken from the malt rather than the weight of the malt.  Do this will all you to compensate for the Working Yield and help you accurately measure your malt bills.  For example, an recipe may call for 5% of caramel 20.  This does not me that you ad 0.5 lbs of caramel 20 malt in a 10 lb recipe. Instead, this means that you will have 5% of the total extract come from the caramel 20 malt.  Use the following formula to calculate the weight of malt based on a percent of extract.

 

 

Lbs malt = (Lbs extract)(% Extract) / WY

 

 

Strike Water Temp

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.

 

 

Strike Temp =  [((0.4)(T mash-T malt)) / L:G] +  T mash

 

 

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.

 

 

gallons H2O =  (Lbs malt)(L:G)(1gallon H2O) / 8.32 lbs water

 

 

Weight of Hops

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.

 

 

Ounces hops = (IBU Target)(galbeer)(IBU%) / (%a-acid)(%Utilization)(7494)

 

 

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.

 

 

60 min = 30% utilization

30 min = 15%

5   min = 2.5%

 

 

The 7494 is a conversion factor and used to cancel the units in the equation.For the hops equation, the units for the % must be expressed in decimal form.  (e.g. 10%= .10)

 

 

Calculation of Wort and Beer Color

 

Color of Wort = S [(% extract)(°L of malt)(°P wort / 8°P reference)]

 

 

We allow for a 30% loss of color during fermentation to calculate the color of beer.

 

Color of Beer = (color of wort)(1 - % color loss)


 

EXAMPLE - PALE ALE

Malt Profiles:

 

HWE

Color

% Extract

Pale

0.76

2

95

Crystal 20

0.70

20

5

BHY = 70%

5 Gallons of beer

14 °P

Mash Temp = 152 °F

Malt Temp = 60 °F

L:G = 3:1

Color Loss = 30%

IBUs = 40

 

Hop Profiles:

 

 

Alpah Acids

Time (min)

% IBUs

%U

Centennial

14%

60

80

32

Cascade

7%

5

20

2.5

 

 


 

PALE ALE ANSWERS:

 

Specific Gravity = 1.057

S.G. = [(14°P) / (258.6 – (14°P/258.2 x 227.1))] +1

 

Lbs extract = 6.16 lbs

Lbs extract =   [(8.32 lbs/gal wort)(5gal wort)(1.057 S.G.)(14 °P)] / 100

 

Working Yield of 2-Row = 0.53

WY =    (0.76 HWE as-is)(70% BHY)

 

Working Yield of C20 = 0.49

WY =    (0.70 HWE as-is)(70% BHY)

 

Lbs of 2-Row = 11.04 lbs

Lbs malt = (6.15Lbs extract)(95% Extract) / 0.53 WY

 

Lbs of C20 = 0.63 lbs

Lbs malt = (6.15 Lbs extract)(5% Extract) / 0.49 WY

 

Total Grain Weight = 11.67 lbs

 

Strike Temperature = 164 degrees F

Strike Temp =  [((0.4)(152 T mash- 60 T malt)) / 3 L:G] +  152 T mash

 

Mash Water Volume = 4.2 Gallons

gallons H2O =  (11.67 Lbs malt)(3 L:G)(1gallon H2O) / 8.32 lbs water

 

Centennial Hops = 0.0.57 oz

Ounces hops = (40 IBU Target)(5 galbeer)(95% IBU) / (14% a-acid)(32% Utilization)(7494)

 

Cascade Hops = 0.76 oz

Ounces hops = (40 IBU Target)(5 galbeer)(5% IBU) / (7% a-acid)(2.5% Utilization)(7494)

 

Color of Wort = 5.07 degrees Lovibond

Color of Wort 2Row = (95% extract)(2°L of malt)(14°P wort / 8°P reference) = 3.32

Color of Wort C10 = (5% extract)(20°L of malt)(14°P wort / 8°P reference) = 1.75

(3.32 + 1.75 = 5.07)

 

Color of Beer = 3.5 degrees Lovibond

Color of Beer = (5.07 color of wort)(1 - 30% color loss)

 

If you make this recipe, add one ounce of Cascade in the sedondary for an excellent dry hop aroma!