The alcohol content or degree of alcohol is the proportion of pure alcohol (i.e. ethanol ) in the total amount of a mixture. In the case of alcohol-water mixtures or alcohol products, it is given as the volume concentration of pure alcohol at 20 degrees Celsius ( Section 2 (4) of the Alcohol Tax Ordinance ), usually in percent by volume (abbreviated unit symbol: % vol. Or vol .-% ), earlier units were degrees Stoppani , Grad Tralles , Grad Gay-Lussac and Grad Sikes. Since alcohol has a much lower density than water, the volume percentage is higher than the weight percentage . The determination of the alcohol content is called alcoholometry .
Legal labeling requirement
The alcohol content in beverages must be specified in the European Union according to Annex XII of the EU Food Information Regulation (LMIV), in Germany previously according to § 7b of the Food Labeling Regulation (LMKV), as a volume percentage with a maximum of one decimal place, followed by "% vol" be; the percentage may be prefixed with "alcohol" or "alc.". Instead of "Alk.", The LKMV provided for "alc." The actual alcohol content may have the following deviations (Annex XII LMIV):
- Beer (under CN code 2203 00) with an alcohol content of up to 5.5% vol, as well as fermented beverages made from grapes under CN code 2206 00 that are not products within the meaning of the Wine Act : 0.5% vol
- Beers with an alcoholic strength of more than 5.5% vol, foaming drinks made from grapes falling within CN code 2206 00, cider , perry, fruit wine and similar drinks made from fruits other than grapes, whether or not sparkling or foaming; Mead / mead : 1.0% vol
- Drinks with pickled fruits or parts of plants: 1.5% vol
- other drinks with an alcohol content of more than 1.2 percent by volume: 0.3% vol
The mere requirement to indicate “volume percent”, however, does not yet determine whether the volume concentration or the volume fraction (or even the volume ratio ) is to be indicated, cf. # Examples of alternative salary information .
Examples of alcohol levels
in percent by volume
Top-fermented beer ( Kölsch , Altbier )
|Burgundy , Bordeaux||10 -14.5|
|Champagne , sparkling wine||10 - 12 , 8|
|Sherry , port , Samos||15 - 22|
|Brandy||36 - 45|
Determination of alcohol content
All salary values that contain the volume term are temperature-dependent. A clear indication of concentrations, volume proportions and volume ratios therefore also includes naming the associated temperature. In the case of alcoholic beverages, this concerns the volumes of the ethanol contained, the water contained and the drink as a mixture. The ordinances stipulate that the alcohol content must be determined at 20 ° C. This indicates ("indicates" indicates here that the texts are unclearly formulated and offer certain room for interpretation) that the statement that one liter of the drink contains 40%, i.e. 400 milliliters (= 40 cl) of alcohol, should be understood as follows: At 20 ° C, one liter of the drink contains an amount of substance or mass of alcohol that would also take up a volume of 400 milliliters at 20 ° C. The relevance of the temperature information is demonstrated / discussed under #Examples for alternative content information . - In practice, it is probably even more important that the direct determination of the alcohol content of a sample by completely “filtering out” ( distilling ) and then measuring the alcohol would be far too time-consuming. Instead, one makes use of the fact that the density of an aqueous ethanol solution is lower, the higher its ethanol content, determines the density of the mixture simply based on how deep a test specimen sinks into the mixture ( Archimedes principle ) and concludes from the measurement result on the alcohol content. However, the relationship between mixture density and alcohol content also depends on the temperature of the mixture. Some measuring devices are provided with a scale that shows the alcohol content of the mixture directly, but only correctly at a certain temperature. The regulations therefore state that instruments that are calibrated for a correct display at a mixture temperature of 20 ° C must be used to determine the alcohol content .
Alternative salary information
Alternative salary sizes
The article DIN 1310 and content information offer in addition to "partial volume to total volume" (volume concentration) at least 12 further possibilities to indicate the alcohol content of a liquid. In medical research and practice for the consumption of alcoholic beverages , mass concentration - around g / l - or mass fraction - around g / kg - are still used.
Section 2 (4) of the Alcohol Tax Ordinance allows, in addition to specifying the volume concentration at 20 ° C, the specification “as mass content in percent by mass”. Because of “percent” cannotmean“ mass concentration ”, the outdated expression “ mass percent ” indicates that the already mentioned mass fraction and not “ mass ratio ” is meant. (The text comes from § 3 of the Spirits Tax Ordinance .)
Conversion of a volume concentration of σ at 20 ° C in the mass concentration β at 20 ° C (see there ) are simple, by multiplication with the density ρ ≈ 0.7893 g · cm -3 of alcohol at 20 ° C: β = σ · ρ . In view of the legally permitted inaccuracy of the volume percent information for alcoholic beverages, it makes sense to calculate with 0.8 instead of 0.789 ..., i.e. 800 g / l . For a beer with 5 percent alcohol by volume, i. H. an alcohol volume concentration of 0.05 gives about 40 g / l; with vodka with 40% vol, the result is around 320 g / l.
By adding the mass concentrations weighted with the volumes of alcoholic beverages consumed by a person on a day / evening, the amount of alcohol consumed and thus the (maximum) blood alcohol concentration ("per mille") according to the Widmark formula can be calculated quite easily. For example, two pints of beer at 40 g / l and a quarter of red wine at 100 g / l (12.5% vol) contain a total of 40 +100/4 = 65 g of alcohol. A man weighing 80 kg can deal with it. The average amount of alcohol consumed daily is also used to assess the health consequences of regular alcohol consumption ( "risk classes" , cancer risk , ...). If 20 to 25 g of alcohol daily is critical (men), one should not drink more than two small pils or a quarter of a liter of wine in the evening .
The mass fraction w is theoretically calculated from the mass concentration β by dividing β by the density ρ m of the total liquid at 20 ° C:
- w = β / ρ m = σ · ρ / ρ m .
However, ρ m does not only depend on the temperature , but (in the case of the mixture with water ), because of the volume contraction, also on the alcohol content itself (which, conversely , can be determined from ρ m ) and can be obtained from a table of empirically determined values. Originally, however, there is only one table that is based on mass fractions (Osborne et al., #Literature ), with which only the volume concentration belonging to w can be calculated using σ = w · ρ m / ρ and “searched” in the other direction got to. The Austrian Pharmacopoeia offers a direct comparison of the proportions by mass and the corresponding volume concentrations at 20 ° C ( #Weblinks ). - The advantage of this difficulty is that the mass fraction does not depend on the volumes and the temperature and is also not affected by the volume contraction (this only comes into play in the relationship to concentrations). The #examples for alternative content information also indicate the correspondence of some mass fractions and volume concentrations, including a summary .
Alternative unit of measure in the US and UK
In the USA, the old English unit of measurement, proof , is also used ; a degree proof corresponds to half a volume percent. However, under Article 27 of the Code of Federal Regulations , manufacturers of spirits are instructed to declare the alcohol content as a percentage by volume.
Information with “Proof” is also available in Great Britain, but its meaning is more complex - see there .
Examples of alternative salary information
The following table compares some mass fractions , volume concentrations at different temperatures and volume fractions of ethanol in ethanol-water mixtures at 20 ° C., given in percent.
|Volume concentration at||Volume
percentage at 20 ° C
|10 ° C||15 ° C||20 ° C||25 ° C||30 ° C||40 ° C|
|12||14.76||14.82||14.88||14.94||15.00||15.10||14.71||Lower limit for spirits|
|47||54.67||54.74||54.80||54.87||54.93||55.05||52.86||Chartreuse Verte (liqueur)|
|73||79.50||79.54||79.58||79.61||79.65||79.71||77.37||Stroh Original (Rum)|
- The sample levels are chosen so that the table values from Osborne et al. ( #Literature ), p. 424 f., Can be used without interpolation (therefore, “crooked” volume fractions appear for the example products instead of the usual per mille information ). There, for every whole percentage and certain temperatures ° C values (index "o" for "Osborne") for the quotient of the corresponding density (index "m" for "mixture") of an ethanol-water mixture, in which ethanol is the mass fraction % and the maximum density (that is at approx. 4 ° C) of water.
- The volume concentration of ethanol to the mass fraction at temperature ° C is calculated as , where the density of ethanol is at ° C. For we are and give the (to tens per thousand rounded) result in the column to ° C in percent. (The legally determined reference temperature of 20 ° C is highlighted in italics. Compared to volume concentration # connections with other content variables , the notation of the variables is slightly modified here.)
- From the mass fraction , the volume concentration (as before) and, analogously, the associated volume concentration of the water at 20 ° C, the volume fraction of ethanol at 20 ° C results as - if - where the density of water is at 20 ° C. For we are and enter the result as a percentage.
- For each mass fraction , the volume concentration between 10 and 40 ° C increases almost linearly with temperature. For light beers, however, 5 degrees only make up about a tenth of a thousandth point, for full beers 1/5 ‰, for red wine a magnitude of half a per mill. In the case of spirits, the temperature dependency initially continues to increase; 5 degrees above port wine, in the spirits range, is an order of magnitude of one per thousand point. As the alcohol content increases, the temperature dependency decreases again and is only as pronounced in spirits known as 80% as in red wines. The differences are far below the error tolerances for labeling .
- The contraction in volume when mixing alcohol and water suggests that the volume fraction of ethanol in a mixture of a volume of alcohol with a volume of water is smaller than the associated volume concentration at the same temperature, the volume of the mixture being from the initial volumes and ; the quotient of the two quantities is a measure of the volume contraction. In the example of 20 ° C, however, the difference in light beer is not even noticeable in tenths of a thousandth point, but it increases - initially - with the alcohol content. In red wine it makes up a full per thousand point, but is still below the error tolerance for labeling. In the case of port wine, the difference exceeds the statutory error tolerance of 0.3%. With brandy a difference of one percentage point is exceeded, with higher alcohol contents there is a difference of more than 2 percentage points, but it is now "slowed down". On the way to 100%, it finally has to go back again, which is not yet visible in the examples.
- Since the quotient of volume fraction and volume concentration remains relatively close to 1, the significantly lower density of alcohol compared to water is reflected in percentages of mass fractions (" mass percent ") that are actually smaller than the associated volume concentrations and volume fractions (" volume percent ") regardless of temperature.
- Degree Spendrup
- Alcohol content of non-alcoholic drinks / meals
- N. S. Osborne, E. C. McKelvy, H. W. Bearce: Density and thermal expansion of ethyl alcohol and of its mixtures with water . In: National Bureau of Standards (ed.): Bulletin of the Bureau of Standards . tape 9 , no. 3 , April 1913, ISSN 0096-8579 , p. 327–474 , doi : 10.6028 / bulletin.215 (pages 424 f. Show relative densities of aqueous ethanol based on 4 ° C water - solutions from 10 to 40 ° C in percentages by mass , explained on p. 423; individual columns appear in Perry's Chemical Engineers' Handbook and in Lange's Handbook of Chemistry , see en: Ethanol (data page) #Properties of aqueous ethanol solutions ; pages 423-425 - physical 98-100 - 92-98 KiB can be downloaded from nistdigitalarchives.contentdm .oclc.org can be downloaded separately; archive.org offers a black and white PDF ("B / W") of 8.2 MB of the entire report compared to 12.3 MB with the original background, navigating through the previous one is also much faster).
- Alcohol content. In: Weinkenner.de. August 25, 2011.
- CVUA Karlsruhe: New problems with mixed drinks containing alcohol after the market adjustment through the Alcopop Tax Act
Martin Kratzel: The problem of the volume percentage. In: PharmXplorer.at. March 5, 2007 (relation to mass percentage, photos demonstrate volume contraction). → From the Austrian Pharmacopoeia:
- 40 alcohol levels in seven different levels in the Google book search, based on percentages by mass, from WM Haynes: CRC Handbook of Chemistry and Physics . 96th edition. CRC Press / Taylor & Francis, Boca Raton FL 2015, ISBN 978-1-4822-6096-0 , pp. 5-124 f .
- ^ A b c Thomas Gilg: Forensic medical aspects of alcohol and alcoholism . In: Manfred V. Singer, Stephan Teyssen (ed.): Alcohol and alcohol-related diseases: Basics - Diagnostics - Therapy . 2nd, completely revised and updated edition. Springer, Berlin Heidelberg 2005, ISBN 978-3-540-22552-2 , p. 551–576 , here p. 552 ( full text in the Google book search).
- ↑ Regulation (EU) No. 1169/2011
- ↑ Corrigendum to Regulation (EU) No. 1169/2011 of the European Parliament and of the Council of October 25, 2011 on consumer information about food and amending Regulations (EC) No. 1924/2006 and (EC) No. 1925 / 2006 of the European Parliament and of the Council and repealing Directive 87/250 / EEC of the Commission, Directive 90/496 / EEC of the Council, Directive 1999/10 / EC of the Commission, Directive 2000/13 / EC of the European Parliament and Council, Commission Directives 2002/67 / EC and 2008/5 / EC and Commission Regulation (EC) No. 608/2004 , accessed on April 25, 2016 In: Official Journal of the European Union. L 304 of November 22, 2011.
- ↑ Except for the lower limit for “light beer”, the unlinked values come from Thomas Gilg: Forensic medical aspects of alcohol and alcoholism . In: Manfred V. Singer, Stephan Teyssen (ed.): Alcohol and alcohol-related diseases: Basics - Diagnostics - Therapy . 2nd, completely revised and updated edition. Springer, Berlin Heidelberg 2005, ISBN 978-3-540-22552-2 , p. 551–576 , here p. 552 ( full text in the Google book search).
- ^ Deutscher Brauerbund e. V .: Light beers: Less alcohol and fewer calories , accessed on December 27, 2018