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what is the original gravity (OG), wort concentration, and alcohol content in brewing? How to measure calculation?

Views: 8552     Author: Alice     Publish Time: 2020-12-17      Origin: https://www.downtheroadbrewery.com/

First of all, [wort concentration (12°P)] and [wort gravity (1.048)] are actually a conversion relation. They both represent the content of extract in wort, that is, the sugar content. General will, the proportion of water is 1.000, so the proportion of wort will be greater than the proportion of water, because the starch in the wort (wort) through enzyme hydrolysis of fermentable sugars and fermentation of sugar, so the proportion of wort must be greater than the proportion of water, so we at the time of conversion, need the proportion of wort minus the basis of the proportion of water are superior in 1000 and in addition to 4. That is: wort concentration (°P)=(wort specific gravity -1)×1000÷4 


Generally, it is more convenient for us to know the wort concentration when we make beer, with the sugar meter can be measured, the unit is °P(read Plato, Plato), so this reverse formula is also more commonly used: wort specific gravity = wort concentration (°P)×0.004+1


For example, wort 11°P, wort specific Gravity =11×0.004+1=1.044 and the Gravity of wort before fermentation is called [Original Gravity(OG)], and the Gravity of wort after fermentation is called [Final Gravity Final Gravity(FG)]. OG > FG. If you divide the two values By 0.0075, you get "Alcohol By Volume (ABV)", vol. That is, the ABV = (OG - FG) / 0.0075

For example: OG = 1.050, FG = 1.012ABV= (1.050 -- 1.012) / 0.0075 = 5.067ABV = 5% (approximately)


International Bitterness Units (IBUs): This is a direct measurement of iso-alpha acid in hops. Basically, 1 IBU is equal to 1 mg of iso-alpha alpha acid in 1 liter of beer. It ranges from 0 (minimum no bitterness) to more than 100, usually above or below a certain range where the average person cannot perceive bitterness (usually IBU below 8 or above 80).

Bitterness Ratio (BU:GU) : The Ratio of IBU in beer to sugar (gravity unit). BU: A GU of 0.5 is considered to be balanced, less than 0.5 is considered sweet, and more than 0.5 is considered bitter.

Bitter ratio formula: the last two digits of IBU divided by OG. Note: CARBON dioxide also balances the bitter taste of the beer, but this formula does not take into account the effect of carbon dioxide.


The formula comes from Ray Daniels, The founder of The Cicerone Certification Program. The Cicerone certification is already the highest industry standard for judging beer sales and service in terms of knowledge and expertise.


For example, 37 IBUs's Pale Ale, OG 1.052, BU:GU = 37/52 = 0.71 Beer color Standard Reference Method (SRM) : provide the numeric range representing beer color. The normal range is 2-50. The darker the color, the bigger the SRM. SRM represents the light absorption of beer at a specific wavelength. It provides an analytical method to measure the color of beer. The CONCEPT of SRM was originally proposed by the American Society of Brewing Chemists.



For example: yellow (1-1.5), straw color (2-3), light yellow (4), gold (5-6), light amber (7), amber (8), moderate amber (9), copper/garnet (10-12), light brown (13-15), brown, red brown or chestnut brown (16-17), coffee (18 to 24), brown, brown (25 to 39), dark brown (40).


Volume of carbon dioxide (V/V) : The volume of dissolved gas per unit volume of liquid. The volume of carbon dioxide usually ranges from 1-3+V/V. The most common volume in the U.S. market is 2.5-2.7. Apparent fermentation degree: It is a simple way to measure the fermentation process in wort, it reflects the process of converting maltose to ethanol. In percentage terms, the AA of most beers ranged from 65% to 80%. To put it more simply: AA above 80% means very little residual sugar. AA less than 60% indicates low degree of fermentation and residual sugar. Formula: AA = [(OG-FG)/(OG-1)]×100 for example: OG = 1.080, FG = 1.020AA = (1.080-1.020)/(1.080-1)] x100AA = (0.060/0.080) x100AA = 0.75 x100AA = 75%

In the brewing process, it is very important to measure and control the concentration of the original wort and the fermented wort. If you would like to know more about beer equipment and purchase them and installation ..., I will be happy to answer your questions. Here is one of the products we offer. 


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