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Basic Brewery calculations, short version NOV 2011

Calculation of Specific Gravity (SGE) from %P of extract in wort at 20 oC:

The extract content (kg extract / hl wort at 20 C) in the wort will be:

kg Extract / hl cold wort = OE%P * SG

This however requires knowledge of the specific gravity (SG)

For quick & dirty calculation only:

SG = 1 + 0.004 * OE%P

This hipshot formula is better for weaker wort than for stronger.

Calculation of Brewhouse yield:

Brewhouse yield =Amount of extract in finished wort / Amount of extract from brewing materials:

Large breweries expect yield > 98 %, and micro breweries may be > 85 %.

Calculation of mash thickness:

The proportion of brewing water to brewing materials is interesting as it indicates thethickness of mash:

Water / Materials = 652.5 / 225 = 2.9 liter water / kg materials

Normal values for this figure for lautertun process will be in the range: 2.83.5depending on the actual mashing recipe.

Volume of mash

As a rule of thumb 1 kg malt grits take up 0.8 l space in the mash.Total mash volume will then be (using numbers from calculation of first wort extract):

652.5 + 0.8 x 225 = 832.5 liter (at 20 oC)

Calculation of OE in kettle full before boiling:

To calculate the OE in the wort kettle before boil, one must know the end gravity (SG),end volume (after evaporation) and the end SG:

Beg SG = OE = End Volume * End SG / Beg Volume

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Calculation of evaporation in wort kettle:

End volume (after boil) = 10 hls (before boil) * 36 / 40 = 9 hls.In other words: 1hls has evaporated during the boil.

Calculation of hop dosing, simplified way only.

Assumptions:

Yield 50%(brewery specific)

-acid in hops pellets: 5 %

Brewsize: 7 hl

5 % -acid in hops

Wanted B.U. x brewsize (hl)Kg hops per brew: ----------------------------------------------------

% Utilisation x % -acid in hops used

Dilution Formula

Dilution/gravity calculations including evaporation calculations in the brewhouseare based on a simple formula using volumes in hls and Specific Gravity (SG):

Beg Volume * Beg SG=End Volume * End SG

(The SG numbers are SG Points, i.e. 1.060 SG = 60 gravity pts, 1.045 = 45 SG pts.)

By re-arranging this formula, we find:

Beg Volume=End Volume * End SG / Beg SG

Beg SG=End Volume * End SG / Beg Volume

End SG=Beg Volume * Beg SG / End Volume

End Volume=Beg Volume * Beg SG / End SG

Degree of fermentation:

The apparent degree of fermentation (ADF) is the value, you read using thesaccharometer. The ADF is approx. = 1.24 * real degree of fermentation (RDF).

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Craft formula: Useful for breweries with limited laboratory instrumentation.

Alcohol calculation from OE: The Craft FormulaIn small breweries the instrumentation in production and in the laboratory may only allowfor measurement of gravities.A hydrometer (saccharometer) may be used to measure the strength of the wort before

fermentation (OE%P) and the apparent extract (EA%) in the beer during processing andin the final beer.As long as no sugar, syrup or water is added to the beer in the tanks,the following new formula will calculate the Percent of Alcohol by Volume (A%vol):

A%vol=(OE%P - EA%) / (2.048 - 0.0126*OE%P) ( The Craft Formula)

Abbreviations used above

OE%P means Original extract in percent Plato g/100gER% means Percent of Real Extract g/100gEA% means Percent of Apparent Extract g/100g

A%mas means Percent of Alcohol by mass g/100gA%vol means Percent of Alcohol by Volume ml/100 mlSGA means Specific Gravity of the Alcohol-containing distillate g/ml over g/mlSGE means Specific Gravity of the Extract-containing reminiscence g/ml over g/mlSGBeer means Specific Gravity of the Beer g/ml over g/ml

Pasteurisation:

One Pasteurisation Unit (PU) is defined as the heat received by 60oC in 1 minute. Theprecise connection is defined as:

PU = time * 1.393 (Temp.60)

Time is measured in seconds/60Temperature is measured in C.

In stead of using this formula, you may simply use this diagramme: