Gravity (alcoholic beverage)
The wort or wort content is a crucial measure in beer brewing. You mean the proportion of dissolved in water from the malt and hops, non-volatile substances before fermentation; it is mainly malt sugar, protein, vitamins and flavorings. The wort has the same meaning as the must for wine making for beer production. So simplification, it is must to wine and spice to beer by the alcoholic fermentation by yeast. The term wort in beer production corresponds to the term degrees Oechsle and KMW degree in winemaking.
- Malt sugar
- Amino acids
- Protein and enzymes ( amylase, maltase, lipase, Peptase )
- Hop components ( oils, aromas, bitter substances, tannins )
The original gravity is the main influencing factor for later alcohol content and nutritional value of the finished beer. The wort is fermented using yeast approximately one third each into alcohol and carbonic acid; the last third of the wort is unvergärbarer residual extract.
The degree Plato is the unit of Original Gravity. Has a wort with n degrees Plato, by definition, the same mass density as an aqueous sucrose solution with n weight percent sucrose. The abbreviation for the unit is ° P. It was named after the German chemist Fritz Plato, who has developed the same measurement system developed in 1843 by the Czech chemist Karl Joseph Napoleon Balling.
Conversion between degrees Plato and mass density
The relationship between degrees Plato and mass density is not linear, a precise calculation can be found in the literature. For relevant in the brewery area around p = 10 ° P and a temperature of T = 20 ° C, but in a very good approximation the following linear formula can be used:
The values for a and b will be often a = 4 kg / (m3 ° P) and B = 1000 kg/m3 is used. This choice of parameters corresponds to the rule of thumb that the original extract from the last two digits of the density results ( in kg/m3 ) divided by four. A density of 1050 kg/m3, therefore, corresponds to an original gravity of 12.5 ° P.
The classification of beers according to their original gravity is in Germany, together with the brewery size, the basis for the beer tax levied.
The wort ( unfermented wort extract content of ) is also crucial for the alcohol content. According to the Balling formula arise from 2.0665 g of extract in fermentation 1 g of alcohol, 0.11 g of yeast and 0.9565 g CO2
The following genera were distinguished beer in Germany for the taxation of beer:
- Simply beers with an original gravity of up to under 7 ° P
- Schankbiere with original wort from 7 ° P to below 11 ° P
- Full beers with a wort from 11 ° P to below 16 ° P
- Strong beers from one wort of 16 ° P or more.
As regards the taxation of beer in Switzerland the following beer genera are distinguished:
- Non-alcoholic beer with an alcohol content not exceeding 0.5 percent by volume
- Light beer with an original gravity to 10.0 ° P
- Plain and specialty beer with a wort of 10.1 ° to 14.0 ° P P
- Strong beer from an original gravity of 14.1 ° P
The most accurate method of analysis to determine the original gravity of beer in retrospect, is the distillation analysis. Through them, with the aid of the formula Balling wort calculated and thus the beer tax to be determined.
- Malc = mass fraction of alcohol in percent
- Ew = extract really in mass percent
In the brewing industry, also referred to as extract content measurement, exist for industrial measurement procedures.
Stammwürzgehalte different beers: