Determination/calculation of the apparent extract content from the SGA20/20 or the density of a liquid
wort, beer, beer-based beverage, NAB, beverage
Determine the SGA20/20 obtained from pycnometry or the density measured with a precision hydrometer or another device for measuring the density. Using the value from the SGA20/20 measurement or the density from the sugar, alcohol, original gravity and correction table according to GOLDINER/KLEMANN, BLOCK, KÄMPF or a polynomial, determine the apparent extract content of the sample.
Determination of the original gravity, alcohol and extract content using an oscillating U-tube density measuring device and an alcohol sensor in beer or beer-based beverages
Aside from the density, the alcohol concentration is also directly measured with an alcohol sensor. This is carried out using catalytic combustion. In a measured stream of air, alcohol vapor rises countercurrent to the beer flowing downwards. The alcohol vapor is oxidized at the sensor and the resultant heat is measured by means of a resistive circuit. This correlates with the concentration of alcohol in the beer. According to Tabarié’s equation, the relationship between the specific gravity of beer, its alcohol content and real extract content can be calculated as follows:
\(\rho_{\text{beer}} = \rho_{\text{alcohol}} \space + \space \rho_{E_R} \space – \space \rho_{\text{water}}\)
\(\text{SG}_{\text{A20/20 beer}} = \text{SG}_{\text{A20/20 alcohol}} \space + \space \text{SG}_{\text{A20/20}}E_R \space – \space \text{SG}_{\text{A20/20 water}}\)
\(\text{SG}_{\text{A20/20 alcohol}} = 1.000\)
Determination/calculation of original gravity, alcohol and real extract content after distillation of beer, beer-based beverages or beverages.
Beer, beer-based beverages, beverages
After distillation of the sample, the original gravity, alcohol and real extract content of the beer in beer-based beverages or other beverages can be determined from the densities of the distillate and residue.
beer, beer-based beverages, beverages
The refraction of a light beam as it passes from an optically less dense (sample liquid) to an optically denser medium (prism) is a function of concentration (alcohol/extract), temperature and wavelength. The density of the test liquid is a function of the concentrations of alcohol and extract content. Therefore, from the refractive index (or alternatively the refractive index nD20 and the density or the SGA20/20, the real extract), the alcohol and original gravity can be determined from nomograms or using regression equations.
Determination of the original gravity, alcohol content and extract using a U-tube density measuring device and near infrared spectroscopy in beer and beer-based beverages
wort, beer, beer-based beverages
The density of the beer is determined with the U-tube density measuring device, while the alcohol content is measured by means of selective alcohol determination through near-infrared spectroscopy. As part of the measurement, the near-infrared absorption is measured at a high resolution at several wavelengths in a narrow spectral range highly specific to alcohol at around 1180 nm and evaluated according to the baseline method. Due to the selectivity of this method for alcohol determination, the calibration is carried out using pure water and a water-ethanol solution of about 10 % vol. From the results for the alcohol content and the density, the calculations are performed according to the Tabarié relationship:
\(\rho_{\text{beer}} = \rho_{\text{alcohol}} \space + \space \rho_{E_R} \space – \space \rho_{\text{water}}\)
\(\text{SG}_{\text{A20/20 beer}} = \text{SG}_{\text{A20/20 alcohol}} \space + \space \text{SG}_{\text{A20/20 ER}} \space – \space \text{SG}_{\text{A20/20 water}}\)
\(\text{SG}_{\text{A20/20 alcohol}} = 1.000\)
This method describes how to determine the extract content of malt used to produce laboratory wort.
Malt intended for use in beer brewing or elsewhere in the food industry
The extract content of malt refers to the compounds from finely ground malt (fine grind), which are brought into solution during a standardized mashing process.
The extract content is determined by the weight ratio sL 20/20 of the wort on the basis of the official sugar tables (Plato tables) at 20 °C. sL 20/20 stands for the weight ratio of a volume of wort at 20 °C to the same volume of water at the same temperature.